Security News > 2021 > May > Microsoft Build Engine Abused for Fileless Malware Delivery
An ongoing campaign abuses the Microsoft Build Engine platform for the fileless delivery of malware, security researchers with threat intelligence firm Anomali reveal.
Described as the build platform for Microsoft and Visual Studio, MSBuild has a feature that allows developers to specify for code to be executed in memory, and adversaries have abused this in a new campaign for the fileless delivery of their malicious payloads.
As part of the campaign, the threat actors encoded executables and shellcode within malicious MSBuild files, and hosted them on a Russian image-hosting website, joxi[.
Anomali's researchers, who reveal that most of the analyzed MSBuild project files used in these attacks were meant to deliver the Remcos RAT as the final payload, could not identify the manner in which these files were being distributed.
Anomali said it was unable to determine who is behind the attacks due to the fact that RemcosRAT and RedLine Stealer are commodity malware.
"The threat actors behind this campaign used fileless delivery as a way to bypass security measures, and this technique is used by actors for a variety of objectives and motivations. This campaign highlights that reliance on antivirus software alone is insufficient for cyber defense, and the use of legitimate code to hide malware from antivirus technology is effective and growing exponentially," Anomali concludes.