SyncAppvPublishingServer
Where this stands
One published detection covers this technique. Every one is unverified — no rule on Siemphony has been executed against real telemetry.
What the technique is
Adversaries may abuse SyncAppvPublishingServer.vbs to proxy execution of malicious PowerShell commands. SyncAppvPublishingServer.vbs is a Visual Basic script associated with how Windows virtualizes applications (Microsoft Application Virtualization, or App-V). For example, Windows may render Win32 applications to users as virtual applications, allowing users to launch and interact with them as if they were installed locally. The SyncAppvPublishingServer.vbs script is legitimate, may be signed by Microsoft, and is commonly executed from \System32 through the command line via wscript.exe. Adversaries may abuse SyncAppvPublishingServer.vbs to bypass PowerShell execution restrictions and evade defensive counter measures by "living off the land." Proxying execution may function as a trusted/signed alternative to directly invoking powershell.exe. For example, PowerShell commands may be invoked using: SyncAppvPublishingServer.vbs "n; {PowerShell}"
Read it on attack.mitre.orgWhat MITRE says you would watch
- AN1220
Execution of SyncAppvPublishingServer.vbs through wscript.exe with a command-line containing embedded PowerShell, proxying malicious PowerShell execution through a Microsoft-signed VBScript interpreter to evade detection and restrictions.
Technique names and descriptions © MITRE ATT&CK®, CC BY 4.0. Not endorsed by MITRE.