dotnet-reverse skill
.NET / C# 二进制逆向。当目标是 .NET assembly(PE 头含 CLR、.exe/.dll 托管程序)、C# 编译产物(含 NativeAOT)、红队 Sharp* 工具(Rubeus / SharpHound / SharpHound 等)、.NET 混淆程序(ConfuserEx / SmartAssembly / Babel / Eazfuscator)、.NET loader / info-stealer / 套壳 malware 时使用。优先用 dnSpyEx + de4dot,需要 AI 直接操作时联动 dnSpy MCP。不用于纯 native 二进制(走 reverse-engineering / ida-reverse)。
Is the dotnet-reverse skill safe?
Clean: nothing in its files matched our rules. We read 4 files in the folder on 2026-09-28.
No findings.
Install the dotnet-reverse skill
A skill is a folder. Copy it into your agent's skills folder and the agent loads it when the task matches its description.
git clone --depth 1 https://github.com/zhaoxuya520/reverse-skill.git /tmp/reverse-skill mkdir -p ~/.claude/skills cp -r /tmp/reverse-skill/skills/dotnet-reverse ~/.claude/skills/dotnet-reverse
In the Claude apps, zip the folder and upload it from the Skills settings. The folder on GitHub
The instructions your agent would load
SKILL.md as published, without the frontmatter. Read it on GitHub
.NET / C# 逆向作业规范
ACTION REQUIRED(读完立刻执行)
- NOW: 用 DIE/file/CLR 头确认目标是 .NET 托管(否则 SWITCH 到 ida-reverse/ / reverse-engineering/)
- NOW: 若疑似混淆 → 先 de4dot 脱壳,产出 *-clean.exe,保留原始样本
- NEXT: dnSpyEx(或 dnSpy MCP / ilspycmd)静态:C# 浏览 + IL 视图看关键判断
- ACT: 需要明文/C2 时动态调试;需要改逻辑时 IL patch 优先于 C# 重编译
- 阶段结束给用户 3–6 项下一步菜单(含导出报告)
适用范围
当任务属于以下场景时优先使用本 skill:
- 识别并逆向 .NET / C# 编译产物(托管 PE / .exe / .dll)
- 分析红队 Sharp* 工具链(Rubeus、SharpHound、SharpShell 等)
- 脱混淆 ConfuserEx / SmartAssembly / Babel / Eazfuscator / .NET Reactor 等壳
- 逆向 .NET loader / info-stealer / RAT 的解密与 C2 逻辑
- 对 C# 程序做 patch(改判断、改常量、keygen)
- 分析 IL2CPP 之前的 Mono/Unity 托管层(注意:IL2CPP 编译后是 native,走 reverse-engineering/ + seed-014)
如果目标是纯 native 二进制(C/C++/Go/Rust 编译、无 CLR),请改用 reverse-engineering/、ida-reverse/ 或 radare2/。
核心原则
- 先识别再下手:先确认是 .NET 托管程序(PE 头 CLR + #~ / #Strings 流 + mscoree _CorExeMain),再决定走 dnSpy 而非 IDA
- IL 优先于 C#:dnSpyEx 的 C# 反编译器会丢失/扭曲信息(编译器生成的状态机、async/await、yield),关键判断与 patch 必须切到 IL 编辑器,C# 视图只用于快速浏览
- de4dot 先行:遇到混淆器先 de4dot 脱一轮再做静态分析,否则字符串/控制流全是乱的
- MCP 联动:环境里若注册了 dnSpy MCP(dnspy_* 工具),优先走 MCP 面做 decompile / IL inspection,避免来回切 GUI
- 证据化输出:脱混淆产物、提取的配置/C2/key、patch diff 都要落盘
工具链映射
前置:Windows 主机装 dnSpyEx + de4dot(choco 或 release);Linux/macOS 用 ilspycmd + dotnet runtime。详见 references/sharp-tools.md 的安装矩阵。
六阶段工作流
1. Identify(识别 .NET)
确认目标是托管程序,别把 native PE 当 .NET 分析:
# Windows
file target.exe # "PE32 executable ... for MS Windows" 不够
# 关键:看有没有 CLR
powershell -c "[System.Reflection.AssemblyName]::GetAssemblyName('target.exe')"
# 或
dnSpyEx 直接拖进去 —— 能打开就是托管
# 通用
strings target.exe | grep -iE "mscoree|_CorExeMain|mscorlib|System\\.".NET 识别标志:
- PE 头 Data Directory[14] (CLR Runtime Header) 非零
- mscoree.dll 导入 / _CorExeMain 入口
- #~、#Strings、#US、#GUID、#Blob metadata 流
- mscorlib / System.Private.CoreLib 字符串
NativeAOT 例外: 编译成 native,没有 CLR 头,但有 System.Private.CoreLib 字符串和重构过的类型元数据 —— 这类走 reverse-engineering/(IDA/r2),本 skill 仅做识别提示。
2. Detect(检测混淆器)
# DIE 快速识别
diec target.exe # Detect It Easy CLI
# 或拖进 dnSpyEx,看是否大量乱码类名 / 控制流变形常见混淆器 → 脱壳策略(详见 references/obfuscators.md):
3. Deobfuscate(脱混淆)
# de4dot 默认自动识别大多数壳
de4dot target.exe -o target-clean.exe
# 指定类型(自动识别失败时)
de4dot --type cfze target.exe # ConfuserEx
de4dot --type sa target.exe # SmartAssembly
# 多层混淆 / de4dot 报 unknown
de4dot --detect target.exe # 看它识别成什么
# 可能要先 patch anti-tamper 再 de4dot(见 references/obfuscators.md)产出:target-clean.exe,后续分析用它。保留原始样本做对照。
4. Static Analyze(静态分析)
dnSpyEx 加载脱壳后样本:
- C# 视图:快速浏览类结构、方法签名、字符串(用于定位)
- IL 视图:关键判断、加密逻辑、状态机必须看 IL(右键 → Edit IL 或 IL 视图)
- 找入口:Main / Startup / 模块初始化器 (Module .cctor)
- 找关键逻辑:搜 flag、password、verify、check、encrypt、http、Config
定位字符串 → 反向引用 → 找到使用它的方法 → IL 视图看判断逻辑5. Dynamic(动态调试)
dnSpyEx 调试器:附加进程 / 启动调试,在关键方法下断点,观察运行时:
- 解密后的明文字符串(很多混淆器的字符串在运行时才解密)
- C2 地址、配置解密结果
- 异常驱动的控制流(anti-debug 常用 try/catch 隐藏真实路径)
.NET 动态调试比 native 友好得多 —— 能直接看到对象值、字符串内容。优先动态而非死磕静态。
6. Patch(按需修改)
dnSpyEx → 右键方法 → Edit Method (C#) 或 Edit IL
- 改判断:ldc.i4.0 → ldc.i4.1(false→true)
- 改常量:直接编辑字符串/数字
- 删除校验:nop 掉整段
File → Save Module → 替换原文件IL patch 可靠性 > C# patch:C# 重编译可能失败(缺引用、语法不对),IL 编辑几乎不会失真。详见 references/common-workflow.md。
触发场景路由
用户说这些时进入本 skill:
- ".NET / C# 二进制逆向" / "C# 程序反编译"
- "dnSpy 分析" / "dnSpyEx patch"
- "ConfuserEx / SmartAssembly / Babel 脱混淆 / 脱壳"
- "Sharp* 工具分析"(Rubeus / SharpHound / SharpShell)
- ".NET malware / loader / info-stealer 逆向"
- "C# 程序 patch / keygen / 修改判断"
何时切出
- IL2CPP 编译的 Unity 游戏 → reverse-engineering/ + seed-014_unity-il2cpp-reverse.md(IL2CPP 是 native,不走 dnSpy)
- NativeAOT 产物 → reverse-engineering/(同上,native)
- 纯 native PE(无 CLR)→ reverse-engineering/ / ida-reverse/
- 需要符号/函数批量迁移到别的版本 → binary-diff/
- 需要画攻击路径 / 调用链图 → diagram-generator/
路由上下文
上游入口: skills/SKILL.md(总控)、routing.md 下游出口:
- IL2CPP / NativeAOT(native)→ reverse-engineering/
- 深度 native .so/.dll 段分析 → ida-reverse/ / radare2/
- 需要 AI 直接操作 dnSpy → 注册并联动 dnSpy MCP(见 references/sharp-tools.md)
同级关联模块:
- reverse-engineering/languages-compiled.md(.NET 简介指向本模块)
- apk-reverse/(Xamarin/MAUI Android 逆向可切回本模块看 C# 层)
参考文档
- references/obfuscators.md — ConfuserEx / SmartAssembly / Babel / Eazfuscator / .NET Reactor 脱混淆详解 + anti-tamper 绕过
- references/common-workflow.md — 完整工作流、IL patch 可靠性、字符串解密器提取、状态机识别
- references/sharp-tools.md — 红队 Sharp* 工具分析、工具安装矩阵、dnSpy MCP 集成、社区资源索引
任务完成自检
- [ ] 是否确认过 CLR / 托管身份(或已 SWITCH 出本 skill)?
- [ ] 混淆样本是否先 de4dot / 等价脱壳再深分析?
- [ ] 关键逻辑是否用 IL 视图验证(而非只看 C# 伪代码)?
- [ ] 产物(clean 样本 / 配置 / patch diff)是否落盘且可复现?
- [ ] 是否提供了下一步菜单或报告出口?
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