The Return of Bumblebee Loader

Despite the disruption of the Bumblebee loader in May 2024, it is once again buzzing around the cyber ecosystem. Recently, Bumblebee was observed utilizing a new infection chain that uses LNK, PowerShell, and MSI files before dropping additional malware. The use of MSI files, a file extension commonly used to install software on the Windows operating system, allows the malware to disguise itself as Nvidia and Midjourney installers. While this specific infection chain is not novel in cybercrime, it is a first for Bumblebee.

What’s notable and unique? 

• Bumblebee Loader is a first-stage malware often used to drop additional malware strains such as ransomware, information stealers, and pen-testing tools like Cobalt Strike. The malware is typically delivered via phishing emails but has also been delivered through other social engineering means.

• This is the first indication of a potential return of the malware following the coordinated law enforcement effort dubbed “Operation Endgame.” Operation Endgame resulted in the seizure of over 100 servers perpetrating ransomware support operations, causing well-known malware loaders, including IceED, Pikabot, Trickbot, Bumblebee, Smokeloaer, and SystemBC, to be heavily degraded. Some of these malware remain non-operational following law enforcement action.

Analyst Comments 

While law enforcement efforts to disrupt cybercrime are notable, the return of the Bumblebee Loader demonstrates the short-lived effect of these interferences, unless persistent operations against the targeted infrastructure can be maintained. To that end, a steady pace of action against cybercriminal operations, such as ransomware groups and the infrastructures they rely upon, is likely the best long-term deterrent to cybercrime. Arete will continue monitoring for both emerging activity from the cybercrime ecosystem and additional law enforcement actions impacting this ecosystem.

Sources 

New Bumblebee Loader Infection Chain Signals Possible Resurgence

New Bumblebee malware replaces Conti’s BazarLoader in cyberattacks

Bumblebee malware returns after recent law enforcement disruption