HackSkills is an organized knowledge base of installable skills that gives AI agents practical security knowledge across areas such as web security, privilege escalation, reverse engineering, and digital forensics. It is intended for bug bounty work, penetration testing, CTF competitions, and authorized security research. The catalogue entries are the project's own master, category, and topic skills.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add yaklang/hack-skills --skill code-obfuscation-deobfuscationgit clone --depth 1 https://github.com/yaklang/hack-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/yaklang/hack-skills/code-obfuscation-deobfuscation)<a href="https://agentmods.dev/skills/yaklang/hack-skills/code-obfuscation-deobfuscation"><img src="https://agentmods.dev/badge/skills/yaklang/hack-skills/code-obfuscation-deobfuscation/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/yaklang/hack-skills/code-obfuscation-deobfuscation"><img src="https://agentmods.dev/badge/skills/yaklang/hack-skills/code-obfuscation-deobfuscation.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket warn
- Snyk pass
- NVIDIA SkillSpector warn
SkillSpector: 2 findings, up to high
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- high Rogue Agent · line 5 Skill modifies its own code, configuration, or behavior at runtime. Self-modification enables an agent to escalate privileges, disable safety constraints, or install persistent backdoors.Fix: Prevent the skill from modifying its own code, SKILL.md, or configuration files. Treat skill files as read-only at runtime.
- high Rogue Agent · line 76 Skill modifies its own code, configuration, or behavior at runtime. Self-modification enables an agent to escalate privileges, disable safety constraints, or install persistent backdoors.Fix: Prevent the skill from modifying its own code, SKILL.md, or configuration files. Treat skill files as read-only at runtime.
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00051 | $0.03525 |
| Opus 5.5 | $0.00020 | $0.01410 |
| Sonnet 5.5 | $0.00010 | $0.00705 |
| Haiku 4.5 | $0.00005 | $0.00352 |
Grade A, and why
code-obfuscation-deobfuscation scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
Copies of this mod
6 near-identical copies found in the catalogue:
- code-obfuscation-deobfuscation — 100% identical, 0 lines differ
- code-obfuscation-deobfuscation — 100% identical, 0 lines differ
- code-obfuscation-deobfuscation — 100% identical, 0 lines differ
- code-obfuscation-deobfuscation — 100% identical, 0 lines differ
- code-obfuscation-deobfuscation — 100% identical, 0 lines differ
- code-obfuscation-deobfuscation — 97% identical, 6 lines differ
How it starts
The opening of the file, as written. The whole thing — 392 lines — stays where its author put it; the contents beside it link to each section on GitHub.
SKILL: Code Obfuscation & Deobfuscation — Expert Analysis Playbook
AI LOAD INSTRUCTION: Expert techniques for identifying, classifying, and defeating code obfuscation in native binaries. Covers junk code, opaque predicates, SMC, control flow flattening, movfuscator, VM protectors (VMProtect/Themida/Code Virtualizer), string encryption, import hiding, and anti-disassembly tricks. Base models often conflate packing with obfuscation and miss the distinction between static and dynamic deobfuscation strategies.
0. RELATED ROUTING
- anti-debugging-techniques when the obfuscated binary also has anti-debug layers
- symbolic-execution-tools when using angr/Z3 for automated deobfuscation
- vm-and-bytecode-reverse for deep VM protector bytecode analysis
Quick identification picks
| Symptom in IDA/Ghidra | Likely Obfuscation | Start With |
|---|---|---|
| Flat CFG, single giant switch | Control flow flattening | Symbolic execution to recover CFG |
Only mov instructions |
movfuscator | demovfuscation / trace-based lifting |
| pushad/pushfd → VM entry | VM protector | Handler table extraction |
| XOR loop before code execution | SMC / string encryption | Dynamic analysis, breakpoint after decode |
| Impossible conditions (opaque predicates) | Junk code insertion | Pattern-based removal |
| All strings unreadable | String encryption | Hook decryption routine, or emulate |
| No imports in IAT | Import hiding | Trace GetProcAddress / hash resolution |
1. JUNK CODE & OPAQUE PREDICATES
1.1 Junk Code Insertion
Dead code that never affects program output, added to increase analysis time.
Identification:
- Instructions that write to registers/memory never read afterward
- Function calls whose return values are discarded and have no side effects
- Loops with invariant bounds that compute unused results
Removal strategy:
- Compute def-use chains (IDA/Ghidra data flow analysis)
- Mark instructions with no downstream use as dead
- Verify removal doesn't change program behavior (trace comparison)
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 392 lines · 51 tokens per session scan A ab19c3ed661d
code-obfuscation-deobfuscation is a skill published in the GitHub repository yaklang/hack-skills (2,521 stars, last pushed 1mo ago), licensed MIT. It adds 51 tokens to every session and 3,525 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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