<\/a><\/figure>\n\n\n\nThe researchers reported that the first-stage GootLoader payload is large and heavily obfuscated, often exceeding 3.5MB. The malicious code executes via the Windows Script Host process (wscript), dropping on the disk a second-stage payload, which is also an obfuscated JavaScript file. The first-stage payload then registers a scheduled task to run the second-stage payload, which is executed immediately after the first stage ends.<\/gwmw><\/p>\n\n\n\n
The second-stage starts execution with script, then it shifts to a cscript process. The cscript instance spawns PowerShell, which deobfuscates and executes a script that begins discovery activities and communicates with the C2 server.<\/p>\n\n\n\n
The stage 3 is the final payload, it is a PowerShell script that performs Discovery\/Reconnaissance activity\u00a0and communicates with C2 to download target malware.<\/gwmw><\/p>\n\n\n\n
“Depending on the version, the usage of the Stage 3\u2019s PowerShell may differ.” concludes the report. “GootLoader 1.0 and 2.0 both utilize PowerShell to reflectively load and execute the .NET based DLL malware as part of post-exploitation. However, GootLoader 3.0 utilizes PowerShell to do both discovery work as well as C2 communication for backdoor command execution, with the executed commands responsible for post-exploitation activity such as downloading additional malware.”<\/gwmw><\/p>\n\n\n\n