🛠️ Obfuscation

This is a work-in-progress. It's indicated with the 🛠️ emoji in the page name or in the category name. Wanna help? Please reach out to me: @_nwodtuhs

Theory

Obfuscation is a way to hide a shellcode. generally symmetric algorithms are used

Practice

Manual obfuscation

Below is a list of ways that allow you to go under the radar of anti-virus software, so put all the chances on your side and use several techniques.
You should also change the logo of the binary as well as its description and its creation date (sandboxes check that the binary is not too recent).

Shellcode encoding

For this part the principle is simple: camouflaged its active load, to do this you will need to code a function to encode, but also to decode, free to choose algorithm this technique works particularly well for static bypass.

Here is a link that will allow you to understand and write your first program:

https://www.ired.team/offensive-security/code-injection-process-injection/writing-custom-shellcode-encoders-and-decoders

Indirect syscall

the principle of this method is to call directly the memory addresses instead of using the API functions an article which explains things very well is this one.

Delayed execution

In order to compromise the machine discreetly, sleeps are also used a lot, There are several methods: WaitForSingleObjectEx, Foliage, Ekko, Deathsleep.

A good part of them are very well explained at the following address : https://evasions.checkpoint.com/techniques/timing.html#delayed-execution

Disable ETW

There are several ways to disable logging, either via nt!EtwpStopTrace, or advapi32!EventWrite but also ntdll!ETWEventWrite.

To better understand these keywords, I invite you to read this article: https://www.binarly.io/posts/Design_issues_of_modern_EDRs_bypassing_ETW-based_solutions/index.html.

Another great resource : https://www.mdsec.co.uk/2020/03/hiding-your-net-etw/.

Automatic obfuscation

Depending on your needs, you can use tools available for the most part on github, they are sorted by category below.

ℹ️ You can also find all the tools in the mindmap section.

Packing

- https://github.com/phra/PEzor
- https://github.com/klezVirus/inceptor
- https://github.com/govolution/avet
- https://github.com/Nariod/RustPacker
- https://github.com/DavidBuchanan314/monomorph
- https://github.com/upx/upx

## Office macro
- https://github.com/sevagas/macro_pack
- https://github.com/optiv/Ivy

AMSI Bypass

- https://github.com/CCob/SharpBlock
- https://github.com/danielbohannon/Invoke-Obfuscation
- https://github.com/klezVirus/Chameleon
- https://github.com/tokyoneon/Chimera

Entropy

https://github.com/kleiton0x00/Shelltropy

LOLBIN

 RemComSvc - https://gist.github.com/snovvcrash/123945e8f06c7182769846265637fedb

Signature hiding

- https://github.com/optiv/ScareCrow
- https://github.com/paranoidninja/CarbonCopy

Resources