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Analyzing position independent code

Skill meltedinhex/analyst-ai-pack/skills/analyzing-position-independent-code

Analyzes position-independent code and shellcode by identifying GetPC/PEB-walk techniques, API-hash resolution loops, and relocation-free addressing so the payload can be disassembled at the right base. Activates for requests to analyze position-independent code, identify PIC techniques, or understand how shellcode resolves APIs without imports.From its SKILL.md

Install
npx -y skills add meltedinhex/analyst-ai-pack --skill analyzing-position-independent-code

Assembled from the repository path, not quoted from the project. Check it against their README if it does not work.

2 things to look at

  • 21 stars21 stars. Stars are a popularity signal and not a quality one, but at this level it is likely that nobody has read this closely except its author, and you would be relying on your own review.
  • runs commandsInstructs the agent to run 1 command, including `python scripts/analyst.py analyze shellcode.bin`.

What its file declares

Copied from the file, not written here

The file declares its own license as Apache-2.0. That is the author’s claim about this one file, and it is not the same thing as the license GitHub reports for the repository, which is listed with the other numbers below.

SKILL.md

2.8 KB, 453 tokens by cl100k_base, as published. Nobody here has run it

Analyzing Position-Independent Code

When to Use

  • You have a PIC blob/shellcode that resolves its own addresses and APIs without imports, and you need to understand its technique before disassembly.
  • You want to identify the base-resolution (GetPC), PEB-walk, and API-hashing mechanics.

Do not use this to execute the code — analyze it statically (and emulate separately if needed). Treat the blob as malicious.

Prerequisites

  • The PIC/shellcode blob (read inertly).

Safety & Handling

  • Read bytes statically; store the blob password-protected and never execute it.

Workflow

Step 1: Identify PIC techniques

python scripts/analyst.py analyze shellcode.bin

Detects GetPC stubs (call $+5/fnstenv), PEB access (fs:[30]/gs:[60]), API-hash loops (lodsb + ror), and stack-string construction.

Step 2: Determine architecture and base behavior

Confirm 32- vs 64-bit PEB access and how the code computes its own base for relative addressing.

Step 3: Map API resolution

Note the hashing algorithm and that resolved APIs are obtained by walking the PEB→LDR→export tables (pair with the API-hash resolver skill).

Step 4: Disassemble at the right base

Load the blob at the inferred base/entry in a disassembler/emulator and proceed.

Validation

  • PIC technique hits reference real patterns (GetPC/PEB/API-hash), not arbitrary bytes.
  • Architecture is consistent with the PEB-access form detected.
  • The analysis points to a concrete entry/base for disassembly.

Pitfalls

  • Encoded/staged shellcode where the PIC patterns appear only after decoding.
  • Mixed 32/64-bit (WoW64) transitions.
  • Custom GetPC variants not matching common signatures.

References

What ships with it: 3 files

3.3 KB alongside SKILL.md, 1 of them executable

references/

scripts/

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