MYRA Fileless Execution via memfd_create and fexecve (Operation Friday Harvest)
Detects the MYRA RAT using memfd_create and fexecve to execute a Rust payload entirely in memory without writing an executable to disk, as observed in the Operation Friday Harvest npm supply chain campaign. The rule looks for process events where the action type indicates process creation, memory allocation, or process access, or where the FolderPath starts with '/proc/' and contains '/fd/'. It specifically targets initiating processes named 'node' or 'npm' or those with command lines associated with npm post-installation scripts. Further filtering is applied to FolderPaths matching the '/proc/\d+/fd/\d+' regex or ProcessCommandLines containing 'memfd_create' or 'fexecve', or FolderPaths containing 'memfd'.
Microsoft Sentinel (KQL)
