Apk Decompiler

Android APK 逆向工程工具集，支持反编译、修改和重新打包。使用场景：(1) 反编译 APK 查看 Smali/Java 源码 (2) 分析应用架构和权限 (3) 修改 UI 文本、功能、逻辑 (4) 重新打包并签名 APK (5) 提取字符串、权限、组件等信息。触发词：反编译 APK、逆向 Androi...

Security Scan

The skill is internally consistent with an APK reverse‑engineering toolkit: its scripts and instructions match the stated purpose and request no unrelated credentials, though it downloads external tooling and writes files to disk so you should review and run it in a controlled environment.

Purpose & Capability

Name/description match the provided scripts and references: decompile.py, analyze.py, rebuild.py and setup_tools.sh implement decompilation, analysis, modification and repackage/sign workflows described in SKILL.md. Required capabilities (Java, unzip, Python) are appropriate and no unrelated credentials or binaries are requested.

Instruction Scope

Runtime instructions are scoped to operating on local APK files and editing Smali/resources. The SKILL.md tells the agent to run setup_tools.sh and the Python scripts which read/write local files under the output/project directories. There are no instructions to read unrelated system files or to transmit analysis results to external endpoints. Note: setup_tools.sh and the scripts will create ~/.apk-tools (or TOOLS_DIR) and download tools — review these downloads before running.

Install Mechanism

No packaged install spec; setup_tools.sh downloads required tooling (baksmali/smali/apktool/dex2jar/uber-apk-signer) from Bitbucket/GitHub releases via curl and unzips dex2jar. These are well-known project hosts, but the script performs network downloads and writes executables/jars to disk (moderate risk if the sources or versions are not verified). This behavior is expected for the skill's purpose.

Credentials

The skill requests no environment variables or credentials by default. It optionally respects TOOLS_DIR for tool storage; this is reasonable. No secret exfiltration or unrelated tokens are requested.

Persistence & Privilege

always is false and the skill does not request forced persistent presence. It writes its own tools into ~/.apk-tools (or TOOLS_DIR), which is normal for a tooling script and limited in scope to its own directory.

Assessment

This skill appears to do what it says: decompile, inspect, modify and rebuild APKs. Before installing or running: (1) review setup_tools.sh to confirm the download URLs and versions (it uses curl to fetch jars/zips and will write to ~/.apk-tools or TOOLS_DIR); (2) run the scripts in an isolated environment (VM/container) if you will process untrusted APKs; (3) verify you have Java and unzip installed; (4) be aware of legal/ethical constraints — modifying and redistributing apps can violate licenses or law; (5) when rebuilding, the tool signs with debug keys (not suitable for publishing). If you want stronger assurance, replace download URLs with checksummed releases or preinstall the required tools from trusted package managers before using the skill.

Android APK 逆向工程工具集，支持完整的反编译、修改和重新打包流程。

快速开始

1. 设置工具

首次使用需要下载必要工具：

cd /path/to/apk-decompiler/scripts
chmod +x setup_tools.sh
./setup_tools.sh

这会下载：

• baksmali/smali - DEX ↔ Smali 转换
• apktool - 资源解码/打包
• dex2jar - DEX → JAR 转换
• uber-apk-signer - APK 签名

2. 反编译 APK

python3 scripts/decompile.py app.apk

输出目录结构：

app-decompiled/
├── smali-out/         # Smali 源码（可编辑）
├── apktool-out/       # 解码的资源文件
│   ├── AndroidManifest.xml
│   ├── res/
│   └── assets/
└── extracted/         # 原始 APK 内容

3. 修改代码/资源

编辑相关文件：

• smali-out/ - 修改 Smali 代码
• apktool-out/AndroidManifest.xml - 修改配置
• apktool-out/res/values/strings.xml - 修改文本

4. 重新打包

python3 scripts/rebuild.py ./app-decompiled

输出：app-rebuilt.apk（已签名）

脚本说明

脚本	功能
setup_tools.sh	下载并设置反编译工具
decompile.py	反编译 APK
rebuild.py	重新打包并签名
analyze.py	分析 APK 结构

常用命令

反编译选项

# 基本反编译
python3 decompile.py app.apk

# 同时生成 JAR（可用 jadx 查看 Java 源码）
python3 decompile.py app.apk --java

# 只解码资源
python3 decompile.py app.apk --resources-only

# 只反编译 Smali
python3 decompile.py app.apk --smali-only

分析选项

# 完整分析
python3 analyze.py app.apk

# 只看权限
python3 analyze.py app.apk --permissions

# 查看 Activities
python3 analyze.py app.apk --activities

# 查看应用类（需要先反编译）
python3 analyze.py app.apk --smali ./smali-out --classes

重新打包选项

# 打包并签名
python3 rebuild.py ./project-dir

# 只签名 APK
python3 rebuild.py ./project-dir --sign-only app.apk

# 跳过签名
python3 rebuild.py ./project-dir --no-sign

修改示例

修改字符串

1. 找到字符串定义：

grep -r "原始文本" ./apktool-out/res/values/

2. 编辑 strings.xml：

<string name="app_name">新名称</string>

修改逻辑（Smali）

1. 找到目标类：

find ./smali-out -name "MainActivity.smali"

2. 编辑 Smali 代码：

# 修改返回值
.method public isEnabled()Z
    const/4 v0, 0x1
    return v0
.end method

3. 参考 references/smali-syntax.md 了解 Smali 语法

修改 AndroidManifest

编辑 apktool-out/AndroidManifest.xml：

• 添加/移除权限
• 修改应用名称
• 添加 Activity
• 启用调试模式

参考 references/android-manifest.md

工具目录

设置完成后，工具存储在 ~/.apk-tools/：

~/.apk-tools/
├── baksmali.jar       # DEX → Smali
├── smali.jar          # Smali → DEX
├── apktool.jar        # 资源解码/打包
├── dex2jar/           # DEX → JAR
└── uber-apk-signer.jar # APK 签名

可设置环境变量：

export TOOLS_DIR=/custom/path

工作流程

┌─────────────┐
│   app.apk   │
└──────┬──────┘
       │ decompile.py
       ▼
┌─────────────────────────┐
│ app-decompiled/         │
│  ├── smali-out/         │ ← 编辑 Smali 代码
│  └── apktool-out/       │ ← 编辑资源/Manifest
└──────┬──────────────────┘
       │ rebuild.py
       ▼
┌─────────────────────┐
│ app-rebuilt.apk     │
│ (已签名，可安装)     │
└─────────────────────┘

注意事项

1. 签名限制：重新打包后使用调试密钥签名，与原应用签名不同

   • 无法覆盖安装原应用
   • 需要先卸载原应用

2. 完整性校验：某些应用会校验签名或文件完整性

   • 需要额外处理绕过校验

3. 混淆代码：ProGuard/R8 混淆后的代码：

   • 类名/方法名会被重命名
   • 需要手动分析理解逻辑

4. 法律风险：仅供学习研究，请勿用于非法用途

环境要求

• Java 运行时 (JRE 8+)
• Python 3.6+
• unzip (通常已预装)