Cybersecurity agencies have warned about the emergence of new variants of the TrueBot malware. This enhanced threat is now targeting companies in the U.S. and Canada with the intention of extracting confidential data from infiltrated systems.

These sophisticated attacks exploit a critical vulnerability (CVE-2022-31199) in the widely used Netwrix Auditor server and its associated agents.

This vulnerability enables unauthorized attackers to execute malicious code with the SYSTEM user's privileges, granting them unrestricted access to compromised systems.

The TrueBot malware, linked with cybercriminal collectives Silence and FIN11, is deployed to siphon off data and disseminate ransomware, jeopardising the safety of numerous infiltrated networks.

The cybercriminals gain their initial foothold by exploiting the cited vulnerability, then proceed to install TrueBot. Once they have breached the networks, they install the FlawedGrace Remote Access Trojan (RAT) to escalate their privileges, establish persistence on the compromised systems, and conduct additional operations.

"During FlawedGrace's execution phase, the RAT stores encrypted payloads within the registry. The tool can create scheduled tasks and inject payloads into msiexec[.]exe and svchost[.]exe, which are command processes that enable FlawedGrace to establish a command and control (C2) connection to 92.118.36[.]199, for example, as well as load dynamic link libraries (DLLs) to accomplish privilege escalation," the advisory says.

The cybercriminals initiate Cobalt Strike beacons within several hours of the first intrusion. These beacons facilitate post-exploitation tasks, including stealing data and installing ransomware or different malware payloads.

While previous versions of the TrueBot malware were typically spread through malicious email attachments, the updated versions leverage the CVE-2022-31199 vulnerability to gain initial access.

This strategic shift allows the cyber threat actors to carry out attacks on a broader scale within infiltrated environments. Importantly, the Netwrix Auditor software is employed by more than 13,000 organizations worldwide, including notable firms such as Airbus, Allianz, the UK NHS, and Virgin.

The advisory does not provide specific information about the victims or the number of organizations affected by the TrueBot attacks.

The report also underlines the participation of the Raspberry Robin malware in these TrueBot attacks, as well as other post-compromise malware like IcedID and Bumblebee. By utilizing Raspberry Robin as a distribution platform, attackers can reach more potential victims and amplify the impact of their malicious activities.

Given that the Silence and TA505 groups are actively infiltrating networks for monetary benefit, it is crucial for organizations to implement suggested security measures.

To safeguard themselves against TrueBot malware and similar threats, organizations should take the following recommendations into account:

• Install updates: Organizations using Netwrix Auditor should install the necessary updates to mitigate the CVE-2022-31199 vulnerability and update their software to version 10.5 or above.
• Enhance security protocols: Deploy multi-factor authentication (MFA) for all employees and services.
• Be vigilant for signs of infiltration (IOCs): Security teams must actively scrutinize their networks for indications of TrueBot contamination. The joint warning provides guidelines to help in discovering and reducing the malware's impact.
• Report any incidents: If organizations detect IOCs or suspect a TrueBot infiltration, they must act swiftly in accordance with the incident response actions laid out in the warning and report the incident to CISA or the FBI.