A new variant of the GootLoader malware, known as GootBot, has emerged as a potent threat capable of evading detection and enabling rapid lateral movement within compromised systems. IBM X-Force researchers, Golo Mühr and Ole Villadsen, have identified this advanced malware, which is introduced by the GootLoader group in the later stages of their attack chain. This strategic shift aims to avoid detection while using common off-the-shelf tools for command and control (C2), such as CobaltStrike or RDP. GootBot is described as a lightweight yet highly effective malware, granting attackers the ability to quickly propagate through networks and deploy additional malicious payloads.
GootLoader, as its name suggests, is known for downloading subsequent malware after luring victims using search engine optimization (SEO) poisoning tactics. Attributed to the threat actor Hive0127 (aka UNC2565), this tactical shift introduces GootBot as a payload post-GootLoader infection, marking a departure from traditional post-exploitation frameworks like CobaltStrike. GootBot operates as an obfuscated PowerShell script, establishing connections with compromised WordPress sites for command and control, allowing it to receive further instructions and commands.
Adding to the challenge of defending against GootBot is its use of a unique hard-coded command and control (C2) server for each deployed GootBot sample. This approach makes it challenging to block malicious traffic effectively. Current campaigns employing GootBot leverage SEO-poisoned search results to deceive victims into downloading an initial payload from compromised sites, designed to resemble legitimate forums.
This initial payload arrives in the form of an archive file, containing an obfuscated JavaScript file that fetches another JavaScript file upon execution. This multi-stage process enables GootBot to perform various tasks, ranging from reconnaissance to carrying out lateral movement, thereby expanding the scope of the attack.
The discovery of the GootBot variant underscores the extent to which attackers are willing to go to operate stealthily and evade detection. This shift in tactics and tools heightens the risk of successful post-exploitation stages, particularly in GootLoader-linked ransomware affiliate activities, highlighting the evolving nature of cybersecurity threats.
