IBM Discovers QakBot Trojan Locking Out Active Directory Users

The financial Trojan isn't just stealing money; it's also locking users out of their enterprise Microsoft Active Directory domains.

Banking Trojan 2

The QakBot financial Trojan has been active since at least 2011 stealing information from banks and end users around the world, but now the attacks have taken a new twist. The QakBot attacks are locking out Microsoft Active Directory (AD) system users, according to research from IBM's X-Force team.

"The X-Force Incident Response and Intelligence Services [IRIS] team observed a spike in the QakBot-related AD lockouts over the past several weeks," Michael Oppenheim, global research lead, IBM X-Force IRIS, told eWEEK.

X-Force has seen AD lockout attacks in the past, which can occur in different ways, from malware assisting in the lockouts to threat actors attempting to utilize stolen credentials and accidentally locking out accounts, Oppenheim said. With QakBot, IBM X-Force researchers found that the malware is attempting to spread through an infected network, utilizing the credentials of the affected machine and user, which in part is triggering the AD lockout issues.

"The Active Directory lockouts are a side effect of how QakBot attempts to spread throughout the network, by trying to reuse infected machines and their accounts, or brute forcing other user name and password combos to attempt to spread to other machines," he said. "The QakBot malware's main purpose is to take over the bank accounts of the business and possibly those of infected employees who browse their online banking at work."

The QakBot malware implements what is known as "man in the browser" functionality that allows injected malicious code to be inserted into online banking sessions. Oppenheim explained that instead of keeping them inside its configuration file, QakBot fetches the malicious scripts on the fly from the domain it controls.

Oppenheim emphasized that QakBot is not actually infiltrating Active Directory itself.

"However, if there are poor credential best practices or if the malware can guess the admin password, then it essentially has the escalated privileges it needs to conduct other operations," he said.

The QakBot malware infects networks in much the same way as any other form of malware. Oppenheim noted that QakBot malware may come through infected websites or via email attachments. That said, he added that the majority of QakBot infections observed by X-Force started via a spearphishing email.


There are several different actions that organizations and end users can take to limit the risk of QakBot infecting their networks. At the most basic level, Oppenheim suggests best practices for web browsing hygiene, including disabling online ads and filtering macro execution in files that come via email, to help keep users safer. 

"To mitigate QakBot activity on the network, companies should make sure that domain accounts are configured with least privilege required to perform job tasks," he said. "Another key is to enforce complex password schemes across the network for all users. This will stop and prevent most brute force attempts from malware."

To help reduce the risk of directory lockouts, Oppenheim said organizations can also opt to creating a Domain Admin account for safety purposes. 

"This special emergency account can work when network users are being locked out, and allow security staff to recover service and determine the source of the lockouts," he said.

Sean Michael Kerner

Sean Michael Kerner

Sean Michael Kerner is an Internet consultant, strategist, and contributor to several leading IT business web sites.