BB ctf-reverse
Provides reverse engineering techniques for CTF challenges. Use when analyzing binaries, game clients, obfuscated code, esoteric languages, custom VMs, anti-debugging, anti-analysis bypass, WASM, .NET, APK (including Flutter/Dart AOT with Blutter), HarmonyOS HAP/ABC, Python bytecode, Go/Rust/Swift/Kotlin binaries, VMProtect/Themida, Ghidra, GDB, radare2, Frida, angr, Qiling, Triton, binary diffing, macOS/iOS Mach-O, embedded firmware, kernel modules, game engines, or extracting flags from compiled executables.
As a process B 70/100 · Nearly there — weak spots: when it triggers, execution cost, running it twice
What is at stake
Medium-severity findings: the skill is probably honest, but read what alarmed the scanner.
Below is the worst case for this category. The finding here is medium: the guard saw a sign, not a proof.
The skill asks for more than the task needs: broad tool access, credential environment variables, binaries. Every extra permission widens the damage from a mistake or a compromise.
Narrow allowed-tools and the variable list to the minimum; replace binaries with readable sources or scripts.
How to improve
- The SKILL.md body is over 5,000 tokens: move reference detail into references/ and load it when needed.
- Your own cases (evals/evals.json, 4–6 real requests with expected answers): the full check would then run those instead of a model-drafted suite.
- A spec.yaml with trigger phrases and assertions — a behaviour contract for CI; `skilltest init` writes a template.
Guard findings · 14
✓ No critical or high findings
Medium and low: 14
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medium Broad scope
meta-broad-allowed-toolsSKILL.md:1Broad tool permissions pre-approved: Bashallowed-tools: Bash Read Write Edit Glob Grep Task WebFetch WebSearch
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low Risky intent
intent-offensive-securitylanguages-compiled.md:197Offensive-security / dual-use content (legitimate for authorised testing; review intended use)**Pattern (see-two):** A Go-compiled C2 client has a UUID embedded via `-ldflags -X`. The C2 server uses mTLS for authentication. To enumerate other clients and their files, patch the UUID to register
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low Risky intent
intent-offensive-securitylanguages-compiled.md:202Offensive-security / dual-use content (legitimate for authorised testing; review intended use)3. Register with the C2 server using the patched binary (mTLS certs are embedded or in distfiles)
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low Secrets in code
secret-high-entropy-tokenlanguages-compiled.md:340High-entropy token-like string (may be an id, hash or a credential) (quoted — discussed, not commanded)swift demangle 's14M…_tF'
quoted -
low Risky intent
intent-offensive-securitypatterns-ctf.md:19Offensive-security / dual-use content (legitimate for authorised testing; review intended use)- [Hash-Resolved Imports / No-Import Ransomware (BSidesSF 2026)](#hash…026)
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low Risky intent
intent-offensive-securitypatterns-ctf.md:521Offensive-security / dual-use content (legitimate for authorised testing; review intended use)## Hash-Resolved Imports / No-Import Ransomware (BSidesSF 2026)
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low Risky intent
intent-offensive-securitypatterns-ctf.md:536Offensive-security / dual-use content (legitimate for authorised testing; review intended use)// hook_crypto.c — captures AES key used by the ransomware
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low Risky intent
intent-offensive-securitypatterns-ctf.md:561Offensive-security / dual-use content (legitimate for authorised testing; review intended use)# Run in Docker container (ransomware may be destructive!)
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low Risky intent
intent-offensive-securitypatterns-ctf.md:563Offensive-security / dual-use content (legitimate for authorised testing; review intended use) (quoted — discussed, not commanded)bash -c "LD_PRELOAD=./hook.so ./ransomware; xxd /tmp/aes_key.bin"
quoted -
low Secrets in code
secret-high-entropy-tokenplatforms.md:118High-entropy token-like string (may be an id, hash or a credential) (quoted — discussed, not commanded)swift demangle 's14M…_tF'
quoted -
low Risky intent
intent-offensive-securitySKILL.md:49Offensive-security / dual-use content (legitimate for authorised testing; review intended use)- [patterns-ctf.md](patterns-ctf.md) - Competition-specific patterns (Part 1): hidden emulator opcodes, LD_PRELOAD key extraction, SPN static extraction, image XOR smoothness, byte-at-a-time cipher, m
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low Risky intent
intent-offensive-securitySKILL.md:367Offensive-security / dual-use content (legitimate for authorised testing; review intended use)## Hash-Resolved Imports / No-Import Ransomware (BSidesSF 2026)
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low Risky intent
intent-offensive-securitySKILL.md:369Offensive-security / dual-use content (legitimate for authorised testing; review intended use) (detector / deny-list definition)**Pattern:** Binary with zero visible imports resolves APIs via symbol name hashing at runtime. Skip the hash reversing — hook OpenSSL functions via `LD_PRELOAD` in Docker to capture AES keys directly
detector
A further 1 matches are quotations in this security skill's documentation and are not counted as findings.
Files scanned: 15. Evidence is masked. Grey chips explain why severity was lowered.
Against the Agent Skills spec
- warning
body-longSKILL.md body ≈ 9221 tokens (recommended < 5000); move details to references/
Process rating: all ten parameters 70/100
- 0Progress reporting. Says nothing while it works
- 20When it triggers. No condition that starts the skill
- 30Running it twice. 6 mutating operations with no state check
- 40Execution cost. Instruction body is 9221 tokens: crowds the task out of the window
- 60Result and completion. Output format stated, no completion criterion
- 70Inputs and preconditions. Inputs and preconditions are listed
- 70Failures and branches. 8 branches
- 100Tools and files. Tools declared in frontmatter
- 100Steps. 49 steps
- 100Consistency. Name and required fields are in place
- low 87 top-level sections: this looks like several domains in one skill
Everything here is measured from the skill text rather than judged by a model, so the numbers are checkable. A parameter weighs more when it is a more common reason for the process to stall.
Quality signals
- +5Description has no quoted example phrases that should trigger the skill
- +4Description does not say when NOT to use the skill (false activations)
- +2Single-language instructions
- +3Description length 515: enough signal without eating the budget
- +4Structure: 95 headings
- +3Step-by-step instructions: 49 items
- +3Output format is stated explicitly
- +4Has examples (10 code blocks)
- +1License stated
Quality base 70; lint remarks subtract, signals add up to 100. Result: 78.