hunting-for-webshells-in-web-servers

通过扫描高熵值文件、可疑的 PHP/JSP/ASP 模式（eval、base64_decode、system、passthru）、 Web 根目录中近期修改的文件以及异常文件大小，检测植入 Web 服务器的 Webshell（网页后门）。使用香农熵（Shannon entropy）计算标记混淆载荷，并通过正则表达式模式匹配已知 Webshell 特征。

9 stars

bykillvxk

View on GitHub Installation ↓

Best use case

hunting-for-webshells-in-web-servers is best used when you need a repeatable AI agent workflow instead of a one-off prompt.

Teams using hunting-for-webshells-in-web-servers should expect a more consistent output, faster repeated execution, less prompt rewriting.

When to use this skill

You want a reusable workflow that can be run more than once with consistent structure.

When not to use this skill

You only need a quick one-off answer and do not need a reusable workflow.
You cannot install or maintain the underlying files, dependencies, or repository context.

Installation

Claude Code / Cursor / Codex

$curl -o ~/.claude/skills/hunting-for-webshells-in-web-servers/SKILL.md --create-dirs "https://raw.githubusercontent.com/killvxk/cybersecurity-skills-zh/main/skills/hunting-for-webshells-in-web-servers/SKILL.md"

Manual Installation

Download SKILL.md from GitHub
Place it in .claude/skills/hunting-for-webshells-in-web-servers/SKILL.md inside your project
Restart your AI agent — it will auto-discover the skill

How hunting-for-webshells-in-web-servers Compares

Feature / Agent	hunting-for-webshells-in-web-servers	Standard Approach
Platform Support	Not specified	Limited / Varies
Context Awareness	High	Baseline
Installation Complexity	Unknown	N/A

Frequently Asked Questions

What does this skill do?

Where can I find the source code?

You can find the source code on GitHub using the link provided at the top of the page.

SKILL.md Source

## 说明

1. 安装依赖：`pip install yara-python`
2. 确定需要扫描的 Web 服务器文档根目录（如 `/var/www/html`、`/opt/lampp/htdocs`）。
3. 运行 Agent 扫描 Webshell：
   - 香农熵分析标记熵值 > 5.5 的文件
   - 模式匹配检测 eval()、base64_decode()、system()、passthru()、shell_exec()
   - 文件修改时间分析发现近期变更的文件
   - 扩展名过滤针对 .php、.jsp、.asp、.aspx、.cgi、.py 文件

```bash
python scripts/agent.py --webroot /var/www/html --output webshell_report.json
```

## 示例

### 高熵 PHP Webshell 检测
```
File: /var/www/html/uploads/img_thumb.php
Entropy: 6.12 (threshold: 5.5)
Patterns matched: eval(), base64_decode(), str_rot13()
Last modified: 2025-12-01 03:42:00 (outside business hours)
Verdict: SUSPICIOUS - likely obfuscated webshell
```

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