Threat Spotlight: The Return of Qakbot Malware

Introduction

The Cylance Threat Guidance team continuously looks for interesting trends and challenges that incite organizations to engage with us. Recently, an influx of thousands of Qakbot (aka Qbot) infections have brought people to us to discuss how to block this malware from gaining access to corporate systems.

Qakbot has been around for years (in fact, we made this video about it last April), but it’s nothing to be complacent about. This malware is well-known for its ability to steal credentials and quickly spread through an enterprise over network shares. Given its age, it might seem logical that security controls would have this threat on lockdown. However, the occasional functional enhancements combined with its multiple layers of obfuscation and server-side polymorphism periodically breathe new life into this seemingly immortal malware.

While it’s unclear why so many systems have suddenly fallen victim to Qakbot, it’s possible that updated exploit kits play a role. After all, there is no shortage of new vulnerabilities and exploits for attackers to use to their advantage.

Since the core functionality of Qakbot has remained fairly consistent over the years and is well documented, we will not rehash that information here. Instead, we’ll evaluate several samples from the recent surge in infections and explore how to correlate unique binaries.

Collecting Qakbot

As highlighted at the beginning of this article, the polymorphic nature of this threat is of great interest given its goal of evading detection. Prior versions of Qakbot configured a scheduled task to request updates, and the recent wave of infections was no different. For example, we observed a sample that configured the following command to run on a weekly basis:

cmd.exe /C “start /MIN C:windowssystem32cscript.exe //E:javascript “C:Users<USER>AppDataLocalMicrosoft<5-8 random alphabetical characters>.wpl””

As described in the command line, the WPL file contains JavaScript. Just (Read more...)

*** This is a Security Bloggers Network syndicated blog from Cylance Blog authored by Cylance Threat Guidance Team. Read the original post at: https://threatmatrix.cylance.com/en_us/home/threat-spotlight-the-return-of-qakbot-malware.html