judge-ctf

by wgpsec

Install this Skill

curl -fsSL -o judge-ctf.zip https://skill.seembox.com/api/v1/skills/judge-ctf/download && unzip judge-ctf.zip

SKILL.md About

---
name: judge-ctf
description: "CTF flag 评判检查清单。当需要判断 CTF 挑战是否完成（flag 是否已获取）、分析攻击失败原因、或为下一步攻击提供精确指导时使用。覆盖 flag 搜索验证、漏洞发现评估、漏洞利用评估、flag 位置推断、常见题型模式匹配（SQLi/LFI/RCE/IDOR/SSRF/反序列化）"
metadata:
  tags: "judge,evaluation,ctf,flag,decision"
  category: "general"
---

# CTF Flag Capture Evaluation Checklist

## Sole Success Criterion

**Has flag{...} been found?**
- Search agent output logs for `flag{`
- Search evidence files for `flag{`
- Search vulns.json detail fields

Found → complete: true, no further evaluation needed.

## Diagnosis When Flag NOT Found

### Step 1: Was any vulnerability discovered?

```
if vuln_count == 0:
    → Insufficient reconnaissance, expand attack surface
    feedback: "No vulnerabilities discovered. Suggestions:
      1. Carefully inspect all HTTP responses for hidden clues
      2. Try directory bruteforce to discover hidden endpoints
      3. Check page source for comments and hidden parameters
      4. Try common default credentials for login"
```

### Step 2: Was the vulnerability exploited?

```
if vulns_found but not_exploited:
    → Insufficient exploitation
    feedback: "Discovered {vuln_type} but did not exploit to get flag. Suggestions:
      - SQLi: Use UNION SELECT to read database tables, find flag table
      - LFI: Read /flag.txt, /home/*/flag, /var/www/flag
      - RCE: find / -name 'flag*' 2>/dev/null
      - IDOR: Enumerate all id values, check each response for flag"
```

### Step 3: Exploited but no flag?

```
if vuln_exploited but no_flag:
    → Flag may not be in expected location
    feedback: "Vulnerability exploited but flag not found. Suggestions:
      1. Database search: SELECT * FROM flags / search all tables
      2. File search: find / grep -r 'flag{' / env | grep FLAG
      3. Check response headers: curl -v for HTTP headers
      4. Check hidden pages: use gained privileges to access /admin, /dashboard
      5. Check source code: decompile/view application source for hardcoded flag"
```

## Common CTF Challenge Patterns

Judge should know these patterns to provide precise feedback:

| Vuln Type | Flag Typically Located |
|-----------|----------------------|
| SQL Injection | A field in some database table |
| LFI/Path Traversal | /flag.txt or /etc/flag or in application directory |
| RCE/Command Injection | Filesystem, requires find/grep |
| IDOR | Content of a specific resource by id |
| Deserialization | Filesystem after gaining RCE |
| SSRF | Response from internal service |
| XSS | Usually no direct flag, unless admin bot exists |
| Info Disclosure | Source comments, backup files, config files |

## Feedback Precision Requirements

**FORBIDDEN**: vague feedback like "keep testing" or "dig deeper".

**MUST** provide specific:
1. Which discovered vulnerability to exploit
2. Concrete exploitation steps (payload-level)
3. Most likely flag location