Microsoft attributes the threat group Knotweed's activities to a professional spyware vendor named DSIRF, who is classified as a private sector offensive actor (PSOA) and is currently employing the commercialised cyberweapon Subzero against their targets.

Microsoft has been following the activities of a threat group known as Knotweed who they have successfully attributed to DSIRF. DSIRF are an Austrian spyware vendor that offer surveillance and intrusion capabilities to organisations willing to use less than ethical tactics.

These services are advertised by the company as information research and digital forensics.

The group have been targeting law firms, banks, and strategic consultancies in the UK as well as Austria and Panama.

Many of the targets are related in some form to the customers of DSIRF that have purchased their services as well as command and control domains related to the actor’s malware activity being owned by DSIRF which helped with attributing Knotweed attacks to DSIRF.

Law firms are being targeted more often in general by threat actors, likely due to the wide variety of targets that threat actors can pivot towards afterwards, and also because of the sensitive information stored during legal disputes.

The most recent attacks by Knotweed have seen exploitation of CVE-2022-22047 - a patch for this vulnerability was released in last month’s publication of Microsoft’s patch on July 12.

Exploitation of this vulnerability may allow Knotweed and other threat actors to gain System level privileges. Furthermore, the attacks are very sophisticated, and the actors go to extensive lengths to evade detection.

This is accomplished through intensive obfuscation of the malware loader which will download the malware into the system’s memory to avoid antivirus that scans files on disk.

Knotweed were investigated by Microsoft due to their development and deployment of the ‘Subzero’ malware which is used to exfiltrate information from victim computers as well phones and other devices connected to the internet.

Subzero is advertised by the organisation on their website as a “state of the art computer surveillance tool”. This tool, and the others in use by either this actor or the many other highly skilled groups, are powerful enough to cause serious concern for the security of their targets and any subsequent victims.

Knotweed has recently been observed using Adobe Reader in combination with zero-day vulnerabilities to infect targets and move through networks to achieve their objectives and the group is not alone in taking advantage of patch delays.

This is an example of a threat actor targeting organisations likely to act as a supply chain to a more promising victim whilst still providing a monetary opportunity.

It is advised that organisations assess which organisations they are connected to that would offer similar risks and identify ways to mitigate this.

Reporting

Report all Fraud and Cybercrime to Action Fraud by calling 0300 123 2040 or online. Forward suspicious emails to report@phishing.gov.uk. Report SMS scams by forwarding the original message to 7726 (spells SPAM on the keypad).