Cryakl Ransomware

Cryakl (AKA Fantomas) is a ransomware-as-a-service tool targeting users throughout Europe, Russia and Eastern Asia. It was first observed in 2014.

Threat ID:: CC-2542
Category:: Ransomware
Threat Severity:: Medium
Threat Vector:: Phishing, Email spam
Published:: 18 July 2018 12:00 AM

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

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Summary

Cryakl (AKA Fantomas) is a ransomware-as-a-service tool targeting users throughout Europe, Russia and Eastern Asia. It was first observed in 2014.

Affected platforms

The following platforms are known to be affected:

Microsoft Windows

Microsoft Windows - All versions

Threat details

It was believed to have been abandoned after its command and control infrastructure was seized in early 2018.

Multiple distribution methods are used to deliver Cryakl based on the requirements of the affiliate user. Earlier versions of the malware were spread as attachments in spam email campaigns, with the attachments varying between 3 types:

A PDF document containing links to a Cryakl executable.
An Office document with malicious macros.
A JavaScript script that loads Cryakl directly.

Later versions would also use legitimate third-party applications or downloader malware as an infection vector. Cryakl could also be delivered as a secondary infection from other malware.

Files are typically encrypted using an asymmetric RSA algorithm; although several variants used an undetermined symmetric algorithm, before being appended with a user-specified extension.

Remediation steps

Type	Step
	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 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 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. Additionally, a number of Cryakl decryption tools have been produced by AV vendors. If users intend to attempt decrypt their files they should ensure they use a tool from a reputable source.

Type

Step

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 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 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.

Additionally, a number of Cryakl decryption tools have been produced by AV vendors. If users intend to attempt decrypt their files they should ensure they use a tool from a reputable source.

Last edited: 17 February 2020 12:41 pm