Clickjacking

SKILL: Clickjacking — Expert Attack Playbook

> AI LOAD INSTRUCTION: Clickjacking (UI redress) techniques. Covers iframe transparency tricks, X-Frame-Options bypass, CSP frame-ancestors, multi-step clickjacking, drag-and-drop attacks, and chaining with other vulnerabilities. Often a "low severity" finding that becomes critical when targeting admin actions.

1. CORE CONCEPT

Clickjacking loads a target page in a transparent iframe overlaid on an attacker's page. The victim sees the attacker's UI but clicks on the invisible target page, performing unintended actions.

  iframe { position: absolute; top: 0; left: 0; width: 100%; height: 100%; opacity: 0.0001; z-index: 2; }
  .decoy { position: absolute; top: 200px; left: 100px; z-index: 1; }

Click to win a prize!

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2. DETECTION — IS THE PAGE FRAMEABLE?

Check X-Frame-Options Header

X-Frame-Options: DENY           → cannot be framed (secure)
X-Frame-Options: SAMEORIGIN     → only same-origin framing (secure for cross-origin)
X-Frame-Options: ALLOW-FROM uri → deprecated, browser support inconsistent
(header absent)                  → frameable! (vulnerable)

Check CSP frame-ancestors

Content-Security-Policy: frame-ancestors 'none'        → cannot be framed
Content-Security-Policy: frame-ancestors 'self'         → same-origin only
Content-Security-Policy: frame-ancestors https://a.com  → specific origin
(directive absent)                                       → frameable

CSP frame-ancestors supersedes X-Frame-Options in modern browsers.

Quick PoC Test

If the page loads in the iframe → frameable → potentially vulnerable.

JavaScript Frame Detection (from target page source)

// Common frame-busting code found in target pages:
if (top.location.hostname !== self.location.hostname) {
    top.location.href = self.location.href;
}

If this code is present but not using CSP frame-ancestors, it can often be bypassed.

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3. PROOF OF CONCEPT TEMPLATES

Basic Single-Click

Free Prize

Click the button to claim your prize!

  iframe { position: absolute; top: 300px; left: 60px;
           width: 500px; height: 200px; opacity: 0.0001; z-index: 2; }

Multi-Step Clickjacking

For actions requiring multiple clicks (e.g., "Are you sure?" confirmation):

  
    Step 1: Click here
  

  Step 2: Confirm

Reposition iframe for each step to align the transparent button with the decoy.

Drag-and-Drop Clickjacking

Extract data from one iframe to another using HTML5 drag-and-drop events — the victim drags across invisible iframes, transferring tokens or data.

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4. BYPASS TECHNIQUES

Frame-Busting Script Bypass

Some pages use JavaScript frame-busting:

if (top !== self) { top.location = self.location; }

Bypass with sandbox attribute:

X-Frame-Options ALLOW-FROM Bypass

ALLOW-FROM is not supported in Chrome/Safari. If the server relies solely on ALLOW-FROM, modern browsers ignore it → page is frameable.

Double-Framing

If X-Frame-Options: SAMEORIGIN is set, but a same-origin page exists that can be framed (without XFO), use that page as an intermediary to frame the target.

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5. HIGH-IMPACT TARGETS

Account deletion page
Email/password change form
Admin panel actions (add user, change role)
Payment confirmation
OAuth authorization ("Allow" button)
Two-factor authentication disable
API key generation
Webhook configuration

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6. TESTING CHECKLIST

□ Check X-Frame-Options header on sensitive pages
□ Check CSP frame-ancestors directive
□ Create iframe PoC and verify page loads
□ Test frame-busting scripts — try sandbox attribute bypass
□ Identify high-value single-click actions
□ For multi-step actions, build multi-click PoC
□ Test both authenticated and unauthenticated pages
□ Verify ALLOW-FROM behavior across browsers

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: yaklang
• Source: yaklang/hack-skills
• License: MIT

Install and usage instructions live in the source repository linked above.