Passive AI Scanner

The passive scanner analyzes proxy traffic in the background and can create Burp issues automatically. It observes existing traffic only and does not send extra requests by itself.

How It Works

1. Proxy traffic is captured as you browse.

2. Requests/responses are filtered (scope, MIME, size, stream patterns).

3. Local checks run before AI calls.

4. Dedup and prompt-result cache reduce repeated analysis.

5. Qualified items are sent to the selected backend.

6. Findings with confidence >= 85% can become [AI Passive] issues.

Passive-to-Active Handoff

Configuration

Core Controls

Setting	Default	Description
Enabled	Off	Toggle in top bar or in the AI Passive Scanner settings tab.
Rate Limit	5s	Minimum delay between analysis requests (range: 1–60).
Scope Only	On	Analyze only in-scope targets.
Max Size (KB)	96	Maximum response size eligible for passive analysis (range: 16–1024).
Min Severity	LOW	Ignore findings below selected severity.

Token/Performance Controls

Setting	Default	Description
Endpoint dedup (min)	30	Skip equivalent method/path analyses inside window.
Response dedup (min)	30	Skip repeated response fingerprints inside window.
Prompt cache TTL (min)	30	Reuse parsed results for identical prompts.
Prompt cache entries	500	Maximum prompt-result cache entries.
Endpoint cache entries	5000	Maximum endpoint dedup entries.
Fingerprint cache entries	5000	Maximum response-fingerprint dedup entries.
Req body chars (AI)	2000	Max request body chars in passive metadata.
Resp body chars (AI)	4000	Max response body chars in passive metadata.
Max headers	40	Max filtered headers in passive metadata.
Max params	15	Max request params in passive metadata.
Req body chars (manual)	4000	Max request body chars for manual context actions.
Resp body chars (manual)	8000	Max response body chars for manual context actions.
Manual context JSON	On (compact)	Compact JSON for context-menu payloads.

If cloud cost is high, lower Resp body chars (AI), Max headers, Max params, and Max Size (KB) before disabling passive scanning entirely.

Screenshot: Passive scanner settings

MIME Type Filtering

The scanner processes text-like content types:

• text/html

• application/json

• application/javascript / text/javascript

• application/xml / text/xml

• text/plain

• unknown (unrecognized textual responses)

Binary assets are skipped.

Detection Rules (Local Checks)

CSRF Token Detection

Patterns include: csrf, xsrf, anti_csrf, csrfmiddlewaretoken, __requestverificationtoken, token.

Dangerous File Upload Extensions

Examples: php, jsp, aspx, cgi, py, jar, war, exe, dll.

Authentication Header Detection

Examples: Authorization, X-API-Key, X-Auth-Token, X-Access-Token.

Session Cookie Detection

Session-like cookie keys: session, auth, token, sid, jwt, remember.

Header Injection Points

Header allowlist used for injection contexts:

• Host

• Origin

• Referer

• X-Forwarded-Host

• X-Forwarded-For

• X-Host

• X-Original-Host

Token and Noise Reduction Pipeline

To reduce model spend while preserving useful evidence:

• Security-focused header filtering (noise headers are dropped).

• Parameter compaction with cache-busting key removal.

• Adaptive body compaction:

  • JSON array sampling,

  • HTML focus on head/forms/inline scripts,

  • bounded raw-text excerpts.

• Endpoint dedup + fingerprint dedup + prompt cache.

Output

Findings View

Open AI Passive Scanner tab -> View findings to inspect:

• timestamp,

• URL,

• title,

• severity,

• detail,

• reasoning (if model provided it),

• confidence.

Issue Creation

Automatic issue creation requires all conditions:

• confidence >= 85%,

• severity passes Min Severity,

• finding is not duplicate-equivalent for same base URL + canonical name.

Issues are prefixed with [AI Passive].

Status Tracking

Passive runtime view includes:

• requests analyzed,

• issues found,

• last analysis time,

• queue size.

Related Pages

• Active AI Scanner

• Settings Reference

• Troubleshooting