JNEC.a Ransomware

JNEC.a is a newly observed ransomware tool exploiting a recently disclosed arbitrary code execution in the WinRAR archiving tool.

Threat ID:: CC-2980
Category:: Ransomware
Threat Severity:: Low
Threat Vector:: Email spam
Published:: 19 March 2019 12:00 AM

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

Summary

JNEC.a is a newly observed ransomware tool exploiting a recently disclosed arbitrary code execution in the WinRAR archiving tool.

Affected platforms

The following platforms are known to be affected:

Android

Microsoft Windows - All versions

WinRAR - Versions prior to 5.70

Threat details

At the time of publication it is unclear how archive files containing JNEC.a are delivered, although there are unconfirmed reports indicating they may be distributed via spam campaigns. When opened, WinRAR will attempt to extract a corrupted image before triggering an error message. Whilst this is happening, an open-source exploit script will load JNEC.a into the Windows Startup folder, where it will deploy when the user next logs in.

Once installed, JNEC.a will encrypt all non-system files using an unknown algorithm before displaying a ransom note within a system dialogue window. File encrypted by JNEC.a are unable to be recovered, even by it's developers, due to an error in the encryption module.

For further information:

CVE-2018-20250

Remediation steps

Type	Step
	RARLab addressed CVE-2018-20250 in WinRAR version 5.70. Users and administrators are encouraged to apply this update immediately. 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

RARLab addressed CVE-2018-20250 in WinRAR version 5.70. Users and administrators are encouraged to apply this update immediately.

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.

CVE Vulnerabilities

Status

CVE-2018-20250

Last edited: 14 February 2020 2:53 pm