MacRansom - Offered as Ransomware-as-a-Service

Security researchers are warning of MacRansom, a new and free MacOS-based ransomware-as-a-service (RaaS) which has been infecting Mac computers for the past several weeks.

Threat ID:: CC-1470
Category:: Ransomware
Threat Severity:: Medium
Threat Vector:
Published:: 21 June 2017 12:00 AM

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Summary

Security researchers are warning of MacRansom, a new and free MacOS-based ransomware-as-a-service (RaaS) which has been infecting Mac computers for the past several weeks.

Threat details

The malware is said to be developed by former Yahoo and Facebook software engineers who believed they had a knack for creating Mac malware.

According to researchers who analysed a sample of MacRansom, a prompt is displayed informing the user the program is from an unidentified developer. Clicking 'open' in this instance allows the ransomware to run.

Once the malware is initiated, it determines whether it's being run in a non-Mac environment or if it's being debugged. If it's not, the ransomware uses symmetric encryption with a hardcoded key to encrypt user files.

The ransomware demands a ransom paid in Bitcoin (BTC) to decrypt their files but researchers are unclear if the files can in fact be decrypted at all.

Remediation steps

Type	Step
	If a computer on your network becomes infected with Ransomware report it to your AV vendor for analysis and patching. Typically Ransomware will begin encrypting local machine files, mapped network drives and files on any shared network storage 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 checking email and browsing the web 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. See Ransomware - Controls to avoid infection for further information 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 report it to your AV vendor for analysis and patching.

Typically Ransomware will begin encrypting local machine files, mapped network drives and files on any shared network storage 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 checking email and browsing the web 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.
See Ransomware - Controls to avoid infection for further information

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 11:34 am