LCRYX Ransomware: How a VB Ransomware Locks Your System
Summary:
LCRYX ransomware, a VBScript-based malware, has resurfaced in February 2025 after its initial emergence in November 2024. The ransomware encrypts files using the ‘.lcryx’ extension and demands a $500 bitcoin ransom for decryption. A researcher recently shared findings on LinkedIn, prompting further analysis of its latest activities and techniques. The ransomware begins by checking for administrative privileges and relaunching itself with elevated rights if needed. It also enables error handling to ensure continued execution despite potential issues.
Once active, LCRYX modifies Windows registry settings to disable key system tools and maintain persistence. It blocks access to system utilities, turns off User Account Control (UAC), and prevents execution of security-related tools, restricting the user’s ability to modify startup configurations or halt the ransomware's execution. To maintain persistence, it sets itself as the default shell and debugger, ensuring execution at system startup and whenever command-line tools are launched. It also hijacks system settings by associating itself with HTTP and HTTPS handlers, enabling execution when web links are clicked.
The ransomware employs various evasion techniques, including process termination of system management tools and disabling security protections from Windows Defender and third-party antivirus software. It disrupts usability by remapping keyboard keys, swapping mouse buttons, and modifying file attributes to make detection and removal difficult. Additionally, it executes a PowerShell command to overwrite the Master Boot Record (MBR), potentially rendering the system unbootable.
Security Officer Comments:
For encryption, LCRYX determines system version compatibility before retrieving specific system folders. It generates a random encryption key and applies a combination of the Caesar cipher and XOR encryption, deleting original files and saving encrypted versions with a new extension. The script iterates through directories, including external drives, maximizing its impact. To prevent file recovery, the ransomware deletes backup files and removes shadow copies and backup catalogs. Upon encryption, LCRYX generates a ransom note on the desktop, instructing victims to visit a website and pay in bitcoin for file decryption. It also downloads and sets a new desktop wallpaper to reinforce its ransom demands. If an internet connection is unavailable, it periodically retries the download.
For further persistence, the ransomware creates additional batch and VBScript files, ensuring execution at startup through registry modifications. One script repeatedly displays a deceptive ransom message and opens a YouTube video while revealing the user’s IP address. Another script continuously terminates system utilities to prevent mitigation efforts. The ransomware also creates random directories to store these malicious files and obfuscate detection.
Suggested Corrections:
IOCs:
https://labs.k7computing.com/index.php/lcryx-ransomware-how-a-vb-ransomware-locks-your-system/
Backup your data, system images, and configurations, regularly test them, and keep the backups offline: Ensure that backups are regularly tested and that they are not connected to the business network, as many ransomware variants try to find and encrypt or delete accessible backups. Maintaining current backups offline is critical because if your network data is encrypted with ransomware, your organization can restore systems.
Update and patch systems promptly: This includes maintaining the security of operating systems, applications, and firmware in a timely manner. Consider using a centralized patch management system; use a risk-based assessment strategy to drive your patch management program.
Test your incident response plan: There's nothing that shows the gaps in plans more than testing them. Run through some core questions and use those to build an incident response plan: Are you able to sustain business operations without access to certain systems? For how long? Would you turn off your manufacturing operations if business systems such as billing were offline?
Check Your Security Team's Work: Use a 3rd party pen tester to test the security of your systems and your ability to defend against a sophisticated attack. Many ransomware criminals are aggressive and sophisticated and will find the equivalent of unlocked doors.
Segment your networks: There's been a recent shift in ransomware attacks – from stealing data to disrupting operations. It's critically important that your corporate business functions and manufacturing/production operations are separated and that you carefully filter and limit internet access to operational networks, identify links between these networks, and develop workarounds or manual controls to ensure ICS networks can be isolated and continue operating if your corporate network is compromised. Regularly test contingency plans such as manual controls so that safety-critical functions can be maintained during a cyber incident.
Train employees: Email remains the most vulnerable attack vector for organizations. Users should be trained on how to avoid and spot phishing emails. Multi-factor authentication can help prevent malicious access to sensitive services.
Link(s):
https://labs.k7computing.com/index.php/lcryx-ransomware-how-a-vb-ransomware-locks-your-system/
LCRYX ransomware, a VBScript-based malware, has resurfaced in February 2025 after its initial emergence in November 2024. The ransomware encrypts files using the ‘.lcryx’ extension and demands a $500 bitcoin ransom for decryption. A researcher recently shared findings on LinkedIn, prompting further analysis of its latest activities and techniques. The ransomware begins by checking for administrative privileges and relaunching itself with elevated rights if needed. It also enables error handling to ensure continued execution despite potential issues.
Once active, LCRYX modifies Windows registry settings to disable key system tools and maintain persistence. It blocks access to system utilities, turns off User Account Control (UAC), and prevents execution of security-related tools, restricting the user’s ability to modify startup configurations or halt the ransomware's execution. To maintain persistence, it sets itself as the default shell and debugger, ensuring execution at system startup and whenever command-line tools are launched. It also hijacks system settings by associating itself with HTTP and HTTPS handlers, enabling execution when web links are clicked.
The ransomware employs various evasion techniques, including process termination of system management tools and disabling security protections from Windows Defender and third-party antivirus software. It disrupts usability by remapping keyboard keys, swapping mouse buttons, and modifying file attributes to make detection and removal difficult. Additionally, it executes a PowerShell command to overwrite the Master Boot Record (MBR), potentially rendering the system unbootable.
Security Officer Comments:
For encryption, LCRYX determines system version compatibility before retrieving specific system folders. It generates a random encryption key and applies a combination of the Caesar cipher and XOR encryption, deleting original files and saving encrypted versions with a new extension. The script iterates through directories, including external drives, maximizing its impact. To prevent file recovery, the ransomware deletes backup files and removes shadow copies and backup catalogs. Upon encryption, LCRYX generates a ransom note on the desktop, instructing victims to visit a website and pay in bitcoin for file decryption. It also downloads and sets a new desktop wallpaper to reinforce its ransom demands. If an internet connection is unavailable, it periodically retries the download.
For further persistence, the ransomware creates additional batch and VBScript files, ensuring execution at startup through registry modifications. One script repeatedly displays a deceptive ransom message and opens a YouTube video while revealing the user’s IP address. Another script continuously terminates system utilities to prevent mitigation efforts. The ransomware also creates random directories to store these malicious files and obfuscate detection.
Suggested Corrections:
IOCs:
https://labs.k7computing.com/index.php/lcryx-ransomware-how-a-vb-ransomware-locks-your-system/
Backup your data, system images, and configurations, regularly test them, and keep the backups offline: Ensure that backups are regularly tested and that they are not connected to the business network, as many ransomware variants try to find and encrypt or delete accessible backups. Maintaining current backups offline is critical because if your network data is encrypted with ransomware, your organization can restore systems.
Update and patch systems promptly: This includes maintaining the security of operating systems, applications, and firmware in a timely manner. Consider using a centralized patch management system; use a risk-based assessment strategy to drive your patch management program.
Test your incident response plan: There's nothing that shows the gaps in plans more than testing them. Run through some core questions and use those to build an incident response plan: Are you able to sustain business operations without access to certain systems? For how long? Would you turn off your manufacturing operations if business systems such as billing were offline?
Check Your Security Team's Work: Use a 3rd party pen tester to test the security of your systems and your ability to defend against a sophisticated attack. Many ransomware criminals are aggressive and sophisticated and will find the equivalent of unlocked doors.
Segment your networks: There's been a recent shift in ransomware attacks – from stealing data to disrupting operations. It's critically important that your corporate business functions and manufacturing/production operations are separated and that you carefully filter and limit internet access to operational networks, identify links between these networks, and develop workarounds or manual controls to ensure ICS networks can be isolated and continue operating if your corporate network is compromised. Regularly test contingency plans such as manual controls so that safety-critical functions can be maintained during a cyber incident.
Train employees: Email remains the most vulnerable attack vector for organizations. Users should be trained on how to avoid and spot phishing emails. Multi-factor authentication can help prevent malicious access to sensitive services.
Link(s):
https://labs.k7computing.com/index.php/lcryx-ransomware-how-a-vb-ransomware-locks-your-system/