Reverse Ctf

Reverse CTF

Goal: solve reverse-engineering CTF tasks with professional methodology, curated challenge patterns, and reproducible evidence.

When this skill applies

• compiled binaries, bytecode, mobile apps, firmware blobs, custom VMs, packed samples, obfuscated scripts, anti-debug logic, or validation algorithms
• tasks requiring static/dynamic analysis, algorithm extraction, patching, emulation, or symbolic execution

Operating model

1. Classify the dominant artifact, primitive, or objective.
2. Load the closest offensive-techniques methodology before selecting tools.
3. Load targeted references only for deep technique details.
4. Choose the smallest tool chain that can produce a validation signal.
5. Record the exact proof path and stop once the objective is reproducible.

Technique integration

Primary methodology to load:

• reversing-technique
• crypto-technique
• forensic-technique

Use these as decision engines. This skill adds challenge-oriented triage, time-boxing, and specialized reverse-CTF patterns.

Tool routing

Prefer these tool families when the corresponding signal appears:

• ghidra
• radare2
• binaryninja
• gdb
• x64dbg
• frida
• dnspy
• apktool
• jadx
• binwalk
• checksec
• strings
• objdump
• readelf
• upx
• patchelf
• strace
• ltrace
• capa
• sagemath
• openssl

Tool syntax belongs in the tool skills. This skill decides when a tool family fits and what output should validate progress.

Solver discipline

• Artifact-first triage, shortest reproducible path, explicit validation signal before pivoting.
• Record failed hypotheses with evidence so an agent does not repeat expensive dead paths.
• Prefer category-specific tools after surface classification; do not run every scanner/brute-forcer by habit.
• End with a replayable proof: recovered secret, local verification, exploit output, decoded artifact, or correlated evidence chain.

Category-specific quick pivots

• Triage format, language/runtime, packing, and anti-analysis before deep decompilation.
• Define objective: recover secret, reconstruct algorithm, bypass check, emulate VM, or extract config.
• Cross-check static hypotheses dynamically and document exact validation signal.

Quality gates

• No claim without a validation signal: recovered secret, replayed exploit, decoded artifact, reproduced model behavior, or corroborated evidence.
• Do not brute force before representation, constraints, and success oracle are known.
• Keep a pivot ledger: hypothesis, evidence, result, next shortest path.
• Keep challenge/platform/competition names out of notes and generated reports.

Resources

Each reference is one reversing lane. Load the file matching your immediate task; cross-links are for adjacent pivots after the first signal.

• references/tools.md — tool routing across the whole loop: triage, Ghidra/radare2/Binary Ninja, GDB/lldb/x64dbg, Frida/angr/Triton, Unicorn/Qiling, oracle breakpoints, bytecode/managed tooling, packers/protectors, deobfuscation, diffing, patching.
• references/languages.md — language-binary recognition and workflow: Go/Rust/Swift/D/C++, Kotlin/JVM/Haskell/Nuitka/.NET, Python bytecode/WASM/esolangs, GNU Make, UEFI.
• references/platforms.md — environment-specific reversing: Apple/Mach-O/iOS, firmware/embedded, kernel drivers, Android apps (JNI/DEX/Frida), desktop bundles (Electron/Tauri/SGX), game engines, exotic architectures.
• references/anti-analysis.md — anti-debug/anti-VM/anti-DBI/code-integrity detection, anti-disassembly, the check→bypass playbook, and signal/handler runtime tricks.
• references/patterns.md — reusable reversing patterns: custom VMs, obfuscation/memory, byte transforms and keystreams, constraint/crypto recovery, runtime oracles and side-channels, hidden control flow.