Security researchers observed that TrickBot has begun using a User Account Control (UAC) bypass to quietly infect machines running Windows 10 without displaying any prompts.
According to Bleeping Computer, security researcher Vitali Kremez observed a new sample of TrickBot analyzing the machine’s OS upon execution. It used the CMSTPLUA UAC bypass if it determined that the machine was running Windows 7. If the computer was running Windows 10, the malware employed the Fodhelper UAC bypass.
Discovered in 2017, the Fodhelper UAC bypass uses C:\Windows\system32\fodhelper.exe, a legitimate Microsoft executable, to execute other programs with administrative privileges. The malware turned to this technique because of its ability to bypass UAC via the registry method. Subsequently, the Trojan used the bypass to launch itself on a machine running Windows 10 without displaying a UAC prompt. In so doing, it did not alert the user, allowing it to quietly discharge its malicious functions.
A Glimpse at TrickBot’s Recent History
The bypass described above is just the latest advancement in TrickBot’s ongoing development. Back in August 2019, for instance, Secureworks discovered that the Trojan had added the ability to solicit PIN codes from mobile customers. These codes could have then allowed the malware to access victims’ voice and text communications via SIM swap fraud.
Several months later, at the beginning of January 2020, SentinelLabs revealed that the malware had added a stealthy backdoor known as PowerTrick to its arsenal. It was just a few weeks later when Bleeping Computer detected an Emotet campaign targeting email addresses at the United Nations with secondary malware payloads such as TrickBot.
How to Defend Against a TrickBot Infection
Security professionals can help their organizations defend against a TrickBot infection by using penetration tests to reveal weak spots in their network defenses. They should also leverage security awareness training and simulated phishing engagements to bolster their email defenses. Doing so will help minimize the risks associated with one of TrickBot’s most common delivery vectors.