TLP AMBER ANNOUNCEMENT:
The Background Intelligent Transfer Service (BITS) is a legitimate Microsoft program used for creating and monitoring jobs over the network. Since it is a Windows legacy program it isn’t widely detected by AV solutions, making it attractive to cybercriminals for malware delivery and persistence. Recent emails targeting the Financial sector utilize BITS functionality by embedding it in heavily obfuscated Word documents, and with the use of LNK files. Monitoring BITS jobs in work environments is important to identify unwanted or unauthorized downloads and uploads. In the past, BITS was used to deliver banking trojans like DarkComet and GlobeImposter ransomware, and it is assessed with high confidence that it will continue to be utilized for both malware delivery and persistence, particularly against Windows based systems that would otherwise be considered highly locked down or security hardened. This report focuses on these two recent implementations of BITS, and looks at other ways BITS is leveraged in the wild.
Wapack Labs has cataloged and reported on malware targeting the financial sector in the past. An archive of related reporting can be found in the Red Sky Alliance portal.
This TLP AMBER report is available only to Red Sky Alliance members.