qkG Filecoder Ransomware Discovered

A new proof-of-concept ransomware called qkG Filecoder (also known as RANSOM_CRYPTOQKG.A), with minor similarities to the Lukitus Locky variant, has been observed being tested using an unusual macro technique.

Threat ID:: CC-1820
Category:: Ransomware
Threat Severity:: Low
Threat Vector:: Macro
Published:: 28 November 2017 12:00 AM

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Summary

Threat details

Typically, macros are used by malware to deliver further payloads or files on to a user’s device. qkG Filecoder differs in that it uses macros to perform the actual encryption as well. Initially delivered by a malicious document, qkG Filecoder runs several macros to enable VBA programming, disable Protected View and remove various security settings. Once this is done the normal.dot Word template is infected.

The normal.dot template is used by Word to store default settings such as font, margins, spacing, etc. Infection of this file would result in any document using it to be infected as well. An encryption macros is inserted into the template, along with an autostart macro (“Document_Close()”) that triggers the encryption when a document is closed. The result of this is that all new Word documents are affected, meaning encryption occurs effectively one file at a time. Infected documents will also carry qkG Filecoder when being transferred, ensuring further infections.

A documents name and file structure are not changed when encrypted, but a note is included with each file containing what is presumed to be the creator’s name “TNA@MHT-TT2”, contact details and ransom demands.

qkG Filecoder’s appears to have three version at present. The first variant includes a decryption routine, although it is currently non-functioning. The second variant contains only a ransom note. The third version uses date-based conditions to effectively randomise the encryption process. Each day of the week is assigned a number e.g. Sunday=1, Monday=2, etc. If this number corresponds to the current time’s minutes, then the file will be encrypted. For example, if it is a Thursday at 12:35 then the file will be encrypted as the minutes amount matches Thursday’s assigned number (:35 corresponds to 5).

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 9:20 am