Troldesh Ransomware

An occurrence of Troldesh ramsomware has affected a California Health Centre in the USA. It encrypted 65,000 patient files stored on a server.

Threat ID:: CC-1044
Category:: Ransomware
Threat Severity:: Medium
Threat Vector:: Email spam
Published:: 5 January 2017 12:00 AM

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

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Summary

An occurrence of Troldesh ramsomware has affected a California Health Centre in the USA. It encrypted 65,000 patient files stored on a server.

Affected platforms

The following platforms are known to be affected:

Microsoft Windows

Microsoft Windows - All versions

Threat details

Troldesh is an aggressive ransomware that is distributed via spam messages which contain a malicious attachment or embedded URLs within the email messages. The URLs redirect the user to download a JavaScript file and a Microsoft Word document.

Opening the malicious file will infect the system and will append files with XTBL or .no_more_ransom. Once this has been completed, a ransom message will be displayed which directs users to a Readme file for more information.

The ransomware can open a communication channel with users for payment instructions. Unlike other ransomware variants, the ransom value can be negotiated with the attackers.

Troldesh is also known as Encoder.858 and Shade.

Threat updates

Date	Update
3 May 2018	Updates Troldesh is now being used to target vulnerable WordPress admin login sites. Traces of these login pages were found in the malicious process's memory.

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.

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.

Last edited: 11 January 2022 3:03 pm