CkSKILLS: Skill for Claude Code

.agents/skills/apk-reversing/SKILL.md

apk-reversing is a skill for Claude Code, Codex from zhaji2333/CkSKILLS. It costs 151 tokens per session (3,276 once invoked), scanned A, original, MIT.

An Android app analysis process that turns an APK—the installable file for an Android app—into readable code, resources, native libraries, and web assets. It also identifies app-protection shells and attempts to restore the hidden contents.

In plain words
What is it for?
Use it to unpack protected Android apps, recover DEX and Java code, extract resources and native libraries, and prepare a complete directory for security auditing.
Why use it?
It provides the real app materials when a protected APK only shows placeholder code or wrapper classes, so later security review can examine what the app actually contains.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions Claude Code; installed under .agents/ (shared by several agents); mentions Codex.

This is zhaji2333/CkSKILLS's own configuration. It tells Claude Code and Codex how to work on CkSKILLS itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything CkSKILLS configures →

Reuse

Borrowing it

Nothing to install: this file belongs to zhaji2333/CkSKILLS. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/zhaji2333/CkSKILLS/main/.agents/skills/apk-reversing/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/zhaji2333/CkSKILLS

Made for: Claude Code, Codex.

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 apk-reversing

README.md
[![agentmods](https://agentmods.dev/badge/skills/zhaji2333/ckskills/apk-reversing/github.svg)](https://agentmods.dev/skills/zhaji2333/ckskills/apk-reversing)
Your own site
<a href="https://agentmods.dev/skills/zhaji2333/ckskills/apk-reversing"><img src="https://agentmods.dev/badge/skills/zhaji2333/ckskills/apk-reversing/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 apk-reversing

Your own site · 80×15
<a href="https://agentmods.dev/skills/zhaji2333/ckskills/apk-reversing"><img src="https://agentmods.dev/badge/skills/zhaji2333/ckskills/apk-reversing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 151 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,276 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 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: 1 finding, 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 86
    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 $0.00151 $0.03276
Opus 5 $0.00076 $0.01638
Sonnet 5 $0.00030 $0.00655
Haiku 4.5 $0.00015 $0.00328

Measured 11d ago against content hash adb39b6853f1, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

apk-reversing scanned grade A 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 11d 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 rootlowPrivilege escalation

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

adb shell "chmod 755 /data/local/tmp/frida-server && /data/local/tmp/frida-server &"

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

.agents/skills/apk-reversing/SKILL.md · 216 lines

How it starts

The opening of the file, as written. The whole thing — 216 lines — stays where its author put it; the contents beside it link to each section on GitHub.

apk-reversing — APK 脱壳与全量反编译还原

定位:这是 android-security-audit上游准备技能——把 APK 变成"可挖的全量源码",交付标准目录后 android-security-audit 直接开挖(密钥追踪/组件安全)。本技能只负责还原,不挖洞;漏洞挖掘见 android-security-audit

只有 APK 有加固壳时才必须完整走本技能;无壳 APK 直接 JADX 反编译即可开工。

何时调用(触发条件)

  • 拿到 APK 但 JADX 打开是 stub/空壳、看不到真实代码
  • 入口类是 com.stub.StubApp / com.secneo.apkwrapper 等加固特征类
  • lib/ 下只有壳 so(libshella、libjiagu、libSecShell 等)
  • 需要提取 so、H5/assets、资源、签名等全量产物
  • android-security-audit 准备标准输入(jadx_out/ + apktool_out/ + lib/ + assets/

标准产物(交付标准)

reversing/<package>/
├── jadx_out/          # Java 源码(JADX 反编译,必须是真实代码而非 stub)
├── apktool_out/       # smali + 资源 + AndroidManifest(apktool)
├── dex/               # 脱壳后的 dex(未合并进 jadx 时单独留档)
├── lib/               # 全部 so(arm64-v8a 优先,可 IDA/Ghidra 打开)
├── assets/            # H5/JS/证书/密钥/配置等资源
├── origin.apk         # 原始 APK 存档
└── report.md          # 壳类型 / 脱壳方式 / 产物清单 / 未还原项

交付检查jadx_out 里能 grep 到真实特征串(appKey/secret/接口域名)、lib/ 的 so 可被 IDA/Ghidra 打开搜导出表、assets/ 的 H5 完整——满足即交付 android-security-audit


一、APK 获取

# 已安装设备上提取
adb shell pm list packages | grep <关键词>            # 找包名
adb shell pm path <package>                           # 拿到 APK 路径
adb pull <路径> origin.apk                            # 拉取

# 模拟器/真机均可;也可应用商店、官网、第三方平台、抓包拦截下载地址
  • 优先取最新版本(厂商 SRC 要求应用商店最新版)
  • 同一 App 多渠道包(小米/华为/Google Play)差异可能影响脱壳难度,可换渠道试

二、壳识别(先识别再脱壳)

快速判断

# 1. 解压看 lib 与入口
unzip -l origin.apk | grep -iE "\.so$|stub|wrapper"
# 2. JADX 打开看 Application/入口类
jadx -d /tmp/quick origin.apk && grep -rn "StubApp\|class.*Application" /tmp/quick/sources/

常见壳特征表

加固 特征(lib/入口类) 脱壳方式
腾讯乐固 libshella-*.so / libtprt.so / com.stub.StubApp frida-dexdump / 模拟器运行 dump
梆梆 libSecShell.so / SecShell frida-dexdump / 反射大师
爱加密 libexec.so / libexecmain.so / com.secneo.apkwrapper frida-dexdump
360 libjiagu.so / libjiagu_x86.so 360 脱壳 / 反射大师
娜迦/顶象 libchaosvmp.so / libddog.so 内存 dump + dex 修复
腾讯御安全/其他 libtosprotection.so frida-dexdump / 运行 dump
DCloud uni-app 无壳 so,assets/apps/<appid>/www/ 无需脱壳,直接提取 www/ 即前端源码

Read the full file on GitHub · 216 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. 11d ago First seen · 216 lines · 151 tokens per session scan A adb39b6853f1

Subscribe to this mod's changes

apk-reversing is a skill published in the GitHub repository zhaji2333/CkSKILLS (80 stars, last pushed 10d ago), licensed MIT. It adds 151 tokens to every session and 3,276 once invoked, about $0.0008 per session on Opus 5. A static security scan graded it A 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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