AceLdr – Cobalt Strike UDRL For Memory Scanner Evasion

A position-independent reflective loader for Cobalt Strike. Zero results from Hunt-Sleeping-Beacons, BeaconHunter, BeaconEye, Patriot, Moneta, PE-sieve, or MalMemDetect. 

Features

Easy to Use

Import a single CNA script before generating shellcode.

Dynamic Memory Encryption

Creates a new heap for any allocations from Beacon and encrypts entries before sleep.

Code Obfuscation and Encryption

Changes the memory containing CS executable code to non-executable and encrypts it (FOLIAGE).

Return Address Spoofing at Execution

Certain WinAPI calls are executed with a spoofed return address (InternetConnectA, NtWaitForSingleObject, RtlAllocateHeap).

Sleep Without Sleep

Delayed execution using WaitForSingleObjectEx.

RC4 Encryption

All encryption performed with SystemFunction032.

Known Issues

• Not compatible with loaders that rely on the shellcode thread staying alive.

References

This project would not have been possible without the following:

• FOLIAGE
• x64 return address spoofing (source + explanation)

Other features and inspiration were taken from the following:

• https://www.arashparsa.com/bypassing-pesieve-and-moneta-the-easiest-way-i-could-find/
• https://github.com/secidiot/TitanLdr
• https://github.com/JLospinoso/gargoyle
• https://www.forrest-orr.net/post/masking-malicious-memory-artifacts-part-ii-insights-from-moneta
• https://www.arashparsa.com/hook-heaps-and-live-free/
• https://blog.f-secure.com/hunting-for-gargoyle-memory-scanning-evasion/
• https://www.elastic.co/blog/detecting-cobalt-strike-with-memory-signatures