TorrentLocker Ransomware

TorrentLocker is a crypto-ransomware that received its name from the registry key used by the malware to store configuration information under ‘HKEY_CURRENT_USER\Software\Bit Torrent Application\Configuration’.

Threat ID:: CC-1262
Category:: Ransomware
Threat Severity:: Medium
Threat Vector:: Email spam
Published:: 16 March 2017 12:00 AM

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

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Summary

Affected platforms

The following platforms are known to be affected:

Microsoft Windows

All Windows Versions

Threat details

TorrentLocker is delivered via a malicious email as an alleged invoice from a supplier of the organisation where the user works. Rather than the invoice being attached to the email, it is viewable by clicking on a Dropbox link provided in the body of the email. By using Dropbox, it allows TorrentLocker to bypass security measures since there is nothing for a filter to scan due to no attachment.

Once the malicious link is opened, a JavaScript file (JS_NEMUCOD) disguised as the invoice will download onto the user's computer. TorrentLocker will then be downloaded and executed from that JavaScript file if opened.

Using multi-layered approach applies to this scenario since there is a need to detect and block malicious attachments and URLs. Endpoint security is also equally important in terms of the protecting servers and other devices across a network to stop attacks at every layer.

TorrentLockers latest malspam campaign abuses the Norton Antivirus brand claiming to be “Payment information”, urging recipients to pay an invoice in what appears to be a Dropbox URL – similar to previous campaigns. Clicking the URL will prompt a user to download a .ZIP archive containing three malicious items.

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 4:48 pm