AMSI

Anti-Malware Scanning Interface

AMSI works by hooking scripting interfaces, looks for known signatures.

This is constantly changing and it's almost pointless to have any code snippets.

Some Bypass Techniques Include:

• Executing from something that doesn't get hooked.

  • Excel 4.0

  • PowerShell v2

• Obfuscation, multiple layers can be deployed to delay detection until after execution has completed.

• Tamper with AMSI before or while it's loaded in memory.

There are a couple of PowerShell tools that help to disable AMSI.

nishang/Bypass/Invoke-AmsiBypass.ps1 at master · samratashok/nishangGitHub

This is a collection of different AMSI bypass techniques, including obfuscation, malicious AMSI.dlls, and MITM attacks against AMSI.dll

GitHub - S3cur3Th1sSh1t/Amsi-Bypass-Powershell: This repo contains some Amsi Bypass methods i found on different Blog Posts.GitHub

Validate that AMSI is disabled.

‘AMSI Test Sample: 7e72c3ce-861b-4339-8740-0ac1484c1386’