# Client Side

> Client-side vulnerability testing - XSS (reflected/stored/DOM), CSRF, CORS misconfiguration, Clickjacking, DOM-based attacks, and Prototype Pollution.

- Skill: `transilienceai/client-side` (Agent Skill, multi-file: 45 files)
- Install (CLI): `npx skillmds add transilienceai/client-side`
- Raw SKILL.md: https://api.skillmd.com/api/skills/transilienceai/client-side/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Security
- Author: transilienceai (https://skillmd.com/u/transilienceai)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/transilienceai/client-side

---


# Client-Side

Test for client-side vulnerabilities across modern web applications and SPAs.

## Techniques

| Type | Key Vectors |
|------|-------------|
| **XSS** | Reflected, Stored, DOM-based, framework-specific (React, Vue, Angular) |
| **CSRF** | Token bypass, SameSite cookie bypass, cross-origin requests |
| **CORS** | Misconfigured origins, null origin, wildcard credentials |
| **Clickjacking** | Frame-based, drag-and-drop, multi-step |
| **DOM-based** | DOM sinks, source/sink analysis, JavaScript URL schemes |
| **Prototype Pollution** | Client-side gadgets, server-side pollution, property injection |

## Workflow

1. Identify input sources and data flows
2. Classify sink contexts (HTML, attribute, URL, JS, CSS)
3. Enumerate defenses (encoding, CSP, sanitizers, Trusted Types)
4. Craft context-appropriate payloads
5. Validate execution and demonstrate impact
6. Document with reproduction steps and remediation

## Reference

- `reference/xss*.md` - XSS bypass techniques and exploitation
- `reference/csrf*.md` - CSRF techniques and bypasses
- `reference/cors*.md` - CORS misconfiguration testing
- `reference/clickjacking*.md` - Clickjacking techniques
- `reference/dom*.md` - DOM-based vulnerability testing
- `reference/prototype-pollution*.md` - Prototype pollution techniques