Windows Proxy Execution of .NET Utilities via Scripts
The following analytic detects the launch of common .NET-related utilities—aspnet_compiler.exe, msbuild.exe, regasm.exe, InstallUtil.exe, or vbc.exe when the parent appears to be a script (batch, CMD, PowerShell,…
Description
The following analytic detects the launch of common .NET-related utilities—aspnet_compiler.exe, msbuild.exe, regasm.exe, InstallUtil.exe, or vbc.exe when the parent appears to be a script (batch, CMD, PowerShell, JScript, VBScript, or HTML) running from an unusual or user-writable Windows location (for example Public, Temp, Fonts, Debug, Recycle Bin, Prefetch, or similar paths), and the child process shows little or no command-line variation from the image path or name. That pattern is consistent with adversaries using trusted .NET binaries as a proxy to run code while hiding execution behind script parents in low-trust folders, behavior associated with techniques such as signed binary proxy execution.
Detection logic
Detection requirements
- Platform
- LinuxmacOSWindows
The rule states no platform. This is derived from the ATT&CK technique it maps to.
- Log source category
- sysmon_eventid_1
Known benign triggers
- No false positives have been identified at this time.
MITRE ATT&CK mappings
0 exclusive techniques.This is coverage no other published rule has; it is not this rule's total technique count.
References
| Reference | Cited by |
|---|---|
| malpedia.caad.fkie.fraunhofer.de/details/win.vipkeylogger | 2 |
| www.broadcom.com/support/security-center/protection-bulletin/vip-keylogger-spreads-via-multi-org-impersonation-campaign | 3 |
| www.joesandbox.com/analysis/1817558/0/pdfexecutive | 2 |
From the source
- At source
- Open at source
- Upstream identifier
- eb59cf01-1874-4d16-b7e4-54a6eb9b3118
- Tagged by the source as
- VIP KeyloggerEndpointendpointSplunk CloudSplunk EnterpriseSplunk Enterprise Securityendpoint
Licence
- Published under
- Apache License 2.0Read the licence
- Attribution
- Required
- Obtained under
- Apache-2.0Read the origin licence
Authorship
- Written by
- Published
- Oct 10, 2026
- Version
- 2