CommonRansom Ransomware

CommonRansom is a newly observed ransomware whose operators offer an unusual method of decrypting files.

Threat ID:: CC-2758
Category:: Ransomware
Threat Severity:: Low
Threat Vector:: Email spam
Published:: 31 October 2018 12:00 AM

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Summary

CommonRansom is a newly observed ransomware whose operators offer an unusual method of decrypting files.

Affected platforms

The following platforms are known to be affected:

Microsoft Windows

Microsoft Windows - All versions

Threat details

At the time of publication it is unclear how CommonRansom is distributed, although there are unconfirmed reports indicating it is being delivered in smaller-scale spam campaigns.

Once installed on a device, CommonRansom will encrypt all non-system files before placing a ransom note on the desktop. This note claims that the user can decrypt their file by opening Remote Desktop Services and providing administration credentials to the threat actors.

Remediation steps

Type	Step
	It is highly unlikely that the threat actors behind CommonRansom will decrypt file if allowed access devices. Affected users are advised to not acknowledge any request for remote access from the threat actors. If a device 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, anti-virus 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 based on the principle 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 affected device and 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 device). 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.

Type

Step

It is highly unlikely that the threat actors behind CommonRansom will decrypt file if allowed access devices. Affected users are advised to not acknowledge any request for remote access from the threat actors.

If a device 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, anti-virus 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 based on the principle 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 affected device and 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 device).

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.

Last edited: 11 January 2022 4:02 pm