LockCrypt Ransomware

LockCrypt is a new server-focused ransomware with similarities to the Satan ransomware-as-a-service. It reportedly infects targets via a Remote Desktop Protocol (RDP) brute-force attack and has targeted smaller businesses in the USA, UK, India, South Africa and the Philippines.

Threat ID:: CC-1789
Category:: Ransomware
Threat Severity:: Medium
Threat Vector:
Published:: 16 November 2017 12:00 AM

Report a cyber attack: call 0300 303 5222 or email [email protected]

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Summary

Threat details

The creators of the malware are manually infecting devices using an RDP brute-force attack performed on compromised servers. Once they have access to a system they terminate all non-core processes before deploying LockCrypt to ensure maximum damage.

LockCrypt encrypts files with .lock extension before installing itself and deleting backups or shadow volumes to prevent easy recovery. Once a system is encrypted the malware sends base64 encoded information to a command & control server in Iran.

Threat updates

Date	Update
23 Nov 2017	Further details concerning the techniques used to deliver the malware have come to light. The RDP brute-force uses a tool called NLBrute to automate the attack. Low-level administration software, such as the Process Hacker tool, are then used to disable AV and database services before removing Volume Shadow Copies. The ransomware is then loaded and run on the unprotected system.

Date

Update

23 Nov 2017

Further details concerning the techniques used to deliver the malware have come to light.

The RDP brute-force uses a tool called NLBrute to automate the attack. Low-level administration software, such as the Process Hacker tool, are then used to disable AV and database services before removing Volume Shadow Copies. The ransomware is then loaded and run on the unprotected system.

Remediation steps

Type	Step
	If a computer on your network becomes infected with ransomware it will begin encrypting local machine files and files on any network the logged-in user has permission to access. For system administration accounts this may include backup storage locations. To avoid becoming infected with ransomware, ensure that: A robust program of education and awareness training is delivered to users to ensure they don’t open attachments or follow links within unsolicited emails. All operating systems, antivirus and other security products are kept up to date. All day to day computer activities such as email and internet are performed using non-administrative accounts and that permissions are always assigned on the basis of least privilege. Your organisation adopts a holistic all round approach to Cyber Security as advocated by the 10 Steps To Cyber Security. Identifying the source of infection: Identifying the infected machine and unplugging / disconnecting or quarantining it from the network is essential to damage limitation. Users should immediately report infections to their IT support provider, disconnect their network cable and power the computer down. File auditing should be enabled and file server logs should be monitored to detect signs of unauthorised encryption and allow the source of encryption to be identified (i.e. the infected PC). To limit the damage of ransomware and enable recovery: All critical data must be backed up, and these backups must be sufficiently protected/kept out of reach of ransomware. Multiple backups should be created including at least one off-network backup (e.g. to tape). The only guaranteed way to recover from a ransomware infection is to restore all affected files from their most recent backup. Additionally, if Remote Desktop Protocol (RDP) is not used then ensure port 3389 (TCP/UDP) is blocked at your internet firewall. If RDP is used, then: Only allow access for authorised RDP users. Enforce strong password policies. Enforce multi-factor authentication. Don't allow RDP access for privileged user accounts. Don’t use generic accounts. Set user accounts with an expiry date. Audit user accounts periodically. Only allow point-to-point connections from specific IP addresses where feasible. Ensure Transport Layer Security (TLS) is up-to-date. Log and monitor all RDP activity and investigate unusual behaviour. Consider only allowing RDP for authorised virtual private network (VPN) connections.

Type

Step

If a computer on your network becomes infected with ransomware it will begin encrypting local machine files and files on any network the logged-in user has permission to access. For system administration accounts this may include backup storage locations.

To avoid becoming infected with ransomware, ensure that:

A robust program of education and awareness training is delivered to users to ensure they don’t open attachments or follow links within unsolicited emails.
All operating systems, antivirus and other security products are kept up to date.
All day to day computer activities such as email and internet are performed using non-administrative accounts and that permissions are always assigned on the basis of least privilege.
Your organisation adopts a holistic all round approach to Cyber Security as advocated by the 10 Steps To Cyber Security.

Identifying the source of infection:

Identifying the infected machine and unplugging / disconnecting or quarantining it from the network is essential to damage limitation.

Users should immediately report infections to their IT support provider, disconnect their network cable and power the computer down.
File auditing should be enabled and file server logs should be monitored to detect signs of unauthorised encryption and allow the source of encryption to be identified (i.e. the infected PC).

To limit the damage of ransomware and enable recovery:

All critical data must be backed up, and these backups must be sufficiently protected/kept out of reach of ransomware.

Multiple backups should be created including at least one off-network backup (e.g. to tape).

The only guaranteed way to recover from a ransomware infection is to restore all affected files from their most recent backup.

Additionally, if Remote Desktop Protocol (RDP) is not used then ensure port 3389 (TCP/UDP) is blocked at your internet firewall.

If RDP is used, then:

Only allow access for authorised RDP users.
Enforce strong password policies.
Enforce multi-factor authentication.
Don't allow RDP access for privileged user accounts.
Don’t use generic accounts.
Set user accounts with an expiry date.
Audit user accounts periodically.
Only allow point-to-point connections from specific IP addresses where feasible.
Ensure Transport Layer Security (TLS) is up-to-date.
Log and monitor all RDP activity and investigate unusual behaviour.
Consider only allowing RDP for authorised virtual private network (VPN) connections.

Last edited: 17 February 2020 11:33 am