Defray Ransomware

A new strain of ransomware known as Defray has been discovered. Similar to other strains of ransomware, Defray is distributed via e-mail and requires social engineering to be successful.

Threat ID:: CC-1612
Category:: Ransomware
Threat Severity:: Medium
Threat Vector:: Phishing
Published:: 30 August 2017 12:00 AM

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Summary

A new strain of ransomware known as Defray has been discovered. Similar to other strains of ransomware, Defray is distributed via e-mail and requires social engineering to be successful.

Affected platforms

The following platforms are known to be affected:

Microsoft Windows

Microsoft Windows - all versions

Threat details

However, Defray is being sent only to specific targets unlike other ransomware strains which tend to be distributed to as many people as possible.

The phishing e-mail contains a personalised message and claims to come from within the targeted user’s organisation. The Defray ransomware is contained within an embedded executable in the Word document. The user is required to double-click the executable in order for Defray to download. Once executed, the ransomware encrypts files on the machine and creates many FILES.txt documents which contain the same message informing the user their files have been encrypted.

Defray will regularly contact a command & control (C2) server to report infection information. Defray is also capable of disabling start-up recovery and in Windows 7, it was reported as been able to delete any program with a graphical user interface (GUI) such as the task manager.

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: 17 February 2020 11:29 am