WooYun Vulnerability Analysis Knowledge Base

Methodology and testing patterns extracted from 88,636 real-world vulnerability cases reported to the WooYun platform (2010-2016).

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When to Use

All testing described here must be performed only against systems you have written authorization to test.

• Penetration testing web applications
• Security code review (server-side or client-side)
• Vulnerability research against web targets you have explicit authorization to test
• Building security test cases or checklists
• Assessing web application attack surface
• Reviewing remediation effectiveness
• Training or education in authorized security testing contexts

When NOT to Use

• Network infrastructure testing (firewalls, routers, switches)
• Mobile application binary analysis
• Malware analysis or reverse engineering
• Compliance-only assessments (PCI-DSS, SOC2 checklists without testing)
• Physical security assessments
• Social engineering campaigns
• Cloud infrastructure misconfigurations (IAM, S3 buckets) — these require cloud-specific tooling, not web vuln patterns

Rationalizations to Reject

These shortcuts lead to missed findings. Reject them:

• "The WAF will catch it" — WAFs are bypass-able; test the application logic, not the middleware
• "It's an internal app, so auth doesn't matter" — internal apps get compromised via SSRF, lateral movement, and credential reuse
• "We already use parameterized queries everywhere" — check for ORM misuse, stored procedures with dynamic SQL, and second-order injection
• "The framework handles XSS" — template engines have raw output modes, JavaScript contexts bypass HTML encoding, and DOM XSS lives entirely client-side
• "File uploads are safe because we check the extension" — extension checks are bypassed via null bytes, double extensions, parser discrepancies, and race conditions
• "We validate on the frontend" — client-side validation is a UX feature, not a security control
• "Nobody would guess that URL" — security through obscurity fails against directory bruteforcing, referrer leaks, and JS source analysis
• "Low severity, not worth reporting" — low-severity findings chain into critical attack paths

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Core Mental Model

Vulnerability = Expected Behavior - Actual Behavior
             = Developer Assumptions + Attacker Input -> Unexpected State

Analysis chain:
1. Where does data come from?  (Input sources)
   -> GET/POST/Cookie/Header/File/WebSocket
2. Where does data flow?       (Data path)
   -> Validation -> Processing -> Storage -> Output
3. Where is data trusted?      (Trust boundaries)
   -> Client / Server / Database / OS / External service
4. How is data processed?      (Processing logic)
   -> Filter / Escape / Validate / Execute
5. Where does data end up?     (Output sinks)
   -> HTML / SQL / Shell / Filesystem / Log / Email

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Attack Surface Mapping

              +-------------------------------------------+
              |         Application Attack Surface         |
              +-------------------------------------------+
                                  |
          +-----------------------+-----------------------+
          |                       |                       |
     +----v----+            +-----v-----+           +-----v-----+
     |  Input  |            | Processing|           |  Output   |
     +---------+            +-----------+           +-----------+
     | GET     |            | Input     |           | HTML page |
     | POST    |    ->      | validation|    ->     | JSON resp |
     | Cookie  |            | Biz logic |           | File DL   |
     | Headers |            | DB query  |           | Error msg |
     | File    |            | File op   |           | Log entry |
     | Upload  |            | Sys call  |           | Email     |
     +---------+            +-----------+           +-----------+

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SQL Injection

Cases: 27,732 | Reference: sql-injection.md | Checklist: sql-injection-checklist.md

High-risk parameters: id, sort_id, username, password, search, keyword, page, order, cat_id

Injection point detection:

• String terminators: ' " ) ') ") -- # /*
• DB fingerprint: @@version (MSSQL), version() (MySQL), v$version (Oracle)

Bypass techniques:

• Whitespace: /**/ %09 %0a ()
• Keywords: SeLeCt sel%00ect /*!select*/
• Equals: LIKE REGEXP BETWEEN IN
• Quotes: 0x hex, char(), concat()

Core defense: parameterized queries (PreparedStatement / ORM binding).

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Cross-Site Scripting (XSS)

Cases: 7,532 | Reference: xss.md | Checklist: xss-checklist.md

Output points: user profile fields (nickname, bio), search reflections, file metadata (filename, alt text), email content (subject, body)

Bypass techniques:

• Tag mutation: <ScRiPt> <script/x> <script\n>
• Event handlers: onerror onload onmouseover onfocus
• Encoding: HTML entities, JS Unicode, URL encoding
• Protocol handlers: javascript: data: vbscript:

Core defense: context-aware output encoding + Content Security Policy.

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Command Execution

Cases: 6,826 | Reference: command-execution.md | Checklist: command-execution-checklist.md

Entry points: system command wrappers (ping, traceroute, nslookup), file operations (compress, decompress, image processing), code eval (eval, assert, preg_replace(/e)), framework vulnerabilities (Struts2, WebLogic, JBoss)

Command chaining:

• Linux: ; | || && \ $()`
• Windows: & | || &&

Bypass techniques:

• Whitespace: ${IFS} $IFS$9 %09 < <>
• Keywords: ca\t ca''t c$@at /???/??t
• Encoding: $(printf "\x63\x61\x74"), `echo Y2F0|base64 -d`

Core defense: avoid shell invocation; use execFile over exec, allowlist acceptable inputs.

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File Upload

Cases: 2,711 | Reference: file-upload.md | Checklist: file-upload-checklist.md

Bypass detection:

• Client-side validation: modify JS or send request directly
• Content-Type: image/gif header + PHP code body
• Extension: .php5 .phtml .pht .php. .php::$DATA
• Content inspection: GIF89a + <?php or image-based webshell
• Parser discrepancy: /upload/1.asp;.jpg (IIS 6.0)

Parser-specific vulnerabilities:

• IIS 6.0: /test.asp/1.jpg, test.asp;.jpg
• Apache: .php.xxx (unknown extension fallback)
• Nginx: /1.jpg/1.php (cgi.fix_pathinfo)
• Tomcat: test.jsp%00.jpg

Core defense: allowlist extensions, rename uploads, store outside webroot, validate content type server-side.

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Path Traversal

Cases: 2,854 | Reference: path-traversal.md | Checklist: path-traversal-checklist.md

High-risk parameters: file, path, filename, url, dir, template, page, include, download

Traversal payloads:

• Basic: ../../../etc/passwd
• Encoded: %2e%2e%2f, ..%252f, %c0%ae%c0%ae/
• Null byte: ../../../etc/passwd%00.jpg
• Windows: ..\..\..\windows\win.ini

Target files (Linux): /etc/passwd, /etc/shadow, /proc/self/environ, /var/log/apache2/access.log

Core defense: resolve canonical paths, validate against allowlisted directories, never use user input in file paths directly.

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Unauthorized Access

Cases: 14,377 | Reference: unauthorized-access.md | Checklist: unauthorized-access-checklist.md

Access types:

• Admin panel exposure: /admin, /manager, /console
• API without authentication: missing token validation, predictable tokens
• Exposed services: Redis (6379), MongoDB (27017), Elasticsearch (9200), Memcached (11211), Docker (2375)
• IDOR: horizontal privilege escalation via ID enumeration

Core defense: authentication + authorization on every endpoint, session management, principle of least privilege.

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Information Disclosure

Cases: 7,337 | Reference: info-disclosure.md | Checklist: info-disclosure-checklist.md

Disclosure sources: error messages with stack traces, exposed .git or .svn directories, backup files (.bak, .sql, .tar.gz), configuration files, debug endpoints, directory listings

Core defense: custom error pages, disable directory listing, remove debug endpoints in production, audit publicly accessible files.

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Business Logic Flaws

Cases: 8,292 | Reference: logic-flaws.md | Checklist: logic-flaws-checklist.md

Vulnerability patterns:

• Password reset: verification code in response body, step skipping, controllable reset tokens
• Authorization bypass: horizontal (ID enumeration), vertical (role escalation)
• Payment logic: amount tampering, quantity manipulation, coupon stacking
• CAPTCHA: not refreshed, reusable, brute-forceable, client-side only

Testing approach:

1. Map the business flow -> draw state transition diagram
2. Identify critical checks -> which parameters determine outcomes
3. Attempt bypass -> modify parameters / skip steps / replay / race
4. Verify impact -> prove the scope of harm

Core defense: server-side validation of all business-critical logic.

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Additional Categories

These categories are derived from case data without full reference documents. Each has a testing checklist extracted from real cases.

Category	Checklist
CSRF	csrf-checklist.md
SSRF	ssrf-checklist.md
Weak Passwords	weak-password-checklist.md
Misconfiguration	misconfig-checklist.md
Remote Code Execution	rce-checklist.md
XML External Entity (XXE)	xxe-checklist.md

Note: The RCE checklist covers deserialization, OGNL injection, and framework-specific remote code execution — distinct from the OS command injection focus of the Command Execution reference above.

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Methodology Case Studies

Real-world penetration testing methodology examples (anonymized):

Case Study	Description
bank-penetration.md	Multi-stage attack chain against a financial institution
telecom-penetration.md	Infrastructure penetration of a telecom carrier

These demonstrate how individual vulnerabilities chain together into full compromise scenarios.

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Testing Priority Framework

High Priority (test first)

1. SQL Injection — direct data access, highest case count (27,732)
2. Command Execution — OS-level compromise
3. File Upload — arbitrary code execution via webshell

Medium Priority

4. Unauthorized Access — second-highest case count (14,377)
5. Business Logic Flaws — application-specific, hard to automate
6. XSS — session hijacking, phishing

Lower Priority (but still important)

7. Path Traversal — file read, sometimes write
8. Information Disclosure — reconnaissance value, enables chaining
9. CSRF/SSRF/XXE — context-dependent severity

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Defense Quick Reference

Vulnerability	Core Defense	Implementation
SQL Injection	Parameterized queries	PreparedStatement / ORM
XSS	Output encoding	Context-aware escaping + CSP
Command Execution	Avoid shell	execFile not exec, allowlist
File Upload	Strict validation	Allowlist ext, rename, isolate
Path Traversal	Canonical paths	Resolve + validate against allowlist
Unauthorized Access	Access control	AuthN + AuthZ + session mgmt
Logic Flaws	Server-side checks	Validate all business logic server-side
Info Disclosure	Minimize exposure	Custom errors, no debug in prod

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Key Insight

All 88,636 vulnerabilities in this database share a common root cause: the gap between what developers assumed and what attackers actually provided. Effective security testing means systematically challenging every assumption at every trust boundary.

Four principles from the data:

1. Boundary thinking — all vulnerabilities occur at trust boundaries
2. Data flow tracing — follow data from input to output completely
3. Assumption challenging — question every "obvious" validation
4. Chain composition — individual low-severity findings combine into critical attack paths