re-fuzzing

re-fuzzing is a skill for Claude Code from dslsdzc/rev-skills. It costs 106 tokens per session (3,174 once invoked), scanned B, original, Apache-2.0.

A workflow for coverage-guided fuzzing, a testing method that automatically feeds many varied inputs to a program while tracking which code paths they reach. It covers AFL++, libFuzzer, honggfuzz, instrumentation, starting test inputs, dictionaries, and structured data.

In plain words
What is it for?
Use it to test file parsers, libraries, and network-protocol parsers, with or without source code, and to run ongoing regression searches for new crashes.
Why use it?
It helps find crashes and other bugs that are hard to discover with a small set of hand-written tests. Tracking code coverage guides the input generation toward less-tested parts of the program.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

Good fit Use it to test file parsers, libraries, and network-protocol parsers, with or without source code, and to run ongoing regression searches for new crashes.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/dslsdzc/rev-skills/re-fuzzing
Install

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.

Any agent
npx skills add dslsdzc/rev-skills --skill re-fuzzing
Clone the repo
git clone --depth 1 https://github.com/dslsdzc/rev-skills

Made for: Claude Code.

Wrote 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.

agentmods badge for re-fuzzing

README.md
[![agentmods](https://agentmods.dev/badge/skills/dslsdzc/rev-skills/re-fuzzing/github.svg)](https://agentmods.dev/skills/dslsdzc/rev-skills/re-fuzzing)
Your own site
<a href="https://agentmods.dev/skills/dslsdzc/rev-skills/re-fuzzing"><img src="https://agentmods.dev/badge/skills/dslsdzc/rev-skills/re-fuzzing/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.

agentmods 80×15 button for re-fuzzing

Your own site · 80×15
<a href="https://agentmods.dev/skills/dslsdzc/rev-skills/re-fuzzing"><img src="https://agentmods.dev/badge/skills/dslsdzc/rev-skills/re-fuzzing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 106 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,174 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 12 findings, up to medium

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 →

  • medium Privilege Escalation · line 24
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 25
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 26
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 39
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 40
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 41
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 28
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 33
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 59
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 62
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 63
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 70
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00106 $0.03174
Opus 5 $0.00053 $0.01587
Sonnet 5 $0.00021 $0.00635
Haiku 4.5 $0.00011 $0.00317

Measured 12d ago against content hash 6092d4362059, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade B, and why

re-fuzzing scanned grade B with 1 finding 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 12d 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.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

- Debian/Ubuntu: `sudo apt install afl++`
.claude/skills/re-fuzzing/SKILL.md · 154 lines

How it starts

The opening of the file, as written. The whole thing — 154 lines — stays where its author put it; the contents beside it link to each section on GitHub.

覆盖率引导模糊测试(AFL++ / libFuzzer / honggfuzz)

何时使用 / 何时不用

  • 用:目标有明确输入面(文件解析 / 库函数 / 网络协议解析),要自动化找崩溃;有源码可插桩(或无源码愿意用 QEMU 模式);需要持续回归找新 bug
  • 不用:目标无输入解析(纯算法/纯逻辑 → 符号执行 [[re-angr]] / [[re-z3]]);已有崩溃只需分析(→ [[re-crash-triage]]);目标是内核/驱动(走 [[re-kernel]] 域思路,不在用户态 fuzz 范围)
  • 不用:只有单个崩溃样本要复现(直接走 [[re-crash-triage]],无需重跑 fuzz)

工具准备

所有工具先验证再使用。fuzz 是动态执行,一律在沙箱内跑([[platform-tips]] 最高原则,见 [[re-sandbox]])。

AFL++ —— 覆盖率引导 fuzz 主力

  • Debian/Ubuntu: sudo apt install afl++
  • Fedora: sudo dnf install american-fuzzy-lop american-fuzzy-lop-clang(包即 AFL++ fork);或源码编译拿最新版(见下)
  • Arch: sudo pacman -S afl++
  • macOS: brew install afl++
  • Windows: WSL2 内 sudo apt install afl++(AFL++ 官方支持 WSL;Windows 本机不可直接跑)
  • 源码编译(推荐,版本最新、含全部模式):
    git clone https://github.com/AFLplusplus/AFLplusplus && cd AFLplusplus
    make distrib        # 需要 clang/LLVM 工具链
    sudo make install
    
  • 验证: afl-fuzz -h(打印 usage 即 OK);afl-clang-fast --version

clang / LLVM —— libFuzzer 宿主 + ASAN 编译器

  • Debian/Ubuntu: sudo apt install clang
  • Fedora/RHEL: sudo dnf install clang
  • Arch: sudo pacman -S clang
  • macOS: Xcode 自带(xcode-select --install 补命令行工具),或 brew install llvm
  • Windows: WSL2 内 Linux 版;本机 Visual Studio 的 clang-cl 亦可(MSVC 支持 /fsanitize=fuzzer
  • 验证: clang --version

libFuzzer —— 库函数 / 单函数 fuzz(随 clang 附带)

  • 无需单独安装:clang 自带,-fsanitize=fuzzer 即启用
  • 验证:
    clang -fsanitize=fuzzer -x c /dev/null -o /tmp/fztest && /tmp/fztest -runs=1
    
    输出含 INFO: libFuzzer 即 OK(/tmp/fztest 用完可删)

honggfuzz —— 硬件计数器 / 多线程 fuzz 备选

  • Debian/Ubuntu: 无官方包 → 源码编译:
    sudo apt install build-essential binutils-dev libunwind-dev libblocksruntime-dev clang
    git clone https://github.com/google/honggfuzz && cd honggfuzz && make
    
  • Fedora/RHEL: sudo dnf install honggfuzz
  • Arch: sudo pacman -S honggfuzz(或 AUR 包 honggfuzz
  • macOS: 无 brew 公式 → 源码编译(需 Xcode + libblocksruntime)
  • Windows: WSL2 内 Linux 版
  • 验证: honggfuzz --help

afl-cov —— 覆盖率统计(gcov/lcov 前端)

Read the full file on GitHub · 154 lines

Changes

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.

  1. 12d ago First seen · 154 lines · 106 tokens per session scan B 6092d4362059

Subscribe to this mod's changes

re-fuzzing is a skill published in the GitHub repository dslsdzc/rev-skills (54 stars, last pushed 14d ago), licensed Apache-2.0. It adds 106 tokens to every session and 3,174 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it B with 1 finding (asks for root). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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