Agent-ready workflow · server

Blind SSRF Callback Evidence

Confirm one outbound server-side request and map protocol, parser, and redirect behavior without touching internal resources.

blind-ssrfoasturl-consumerwebhookegress
Stable IDworkflow:blind-ssrf-callback-evidenceSource record dateHuman reviewNot recordedProvenanceCurated workflow graph

Enter with artifacts, leave with evidence.

Use when
  • URL field
  • webhook
  • preview
  • import
  • remote media
  • PDF renderer
Prerequisites
  • current scope
  • controlled listener
  • known URL-consuming feature
MCP retrieval

Agents can search this workflow, retrieve the complete graph, or request one stage through the read-only Vulns.co MCP connector.

01

Classify the URL consumer

Separate validation, save, preview, fetch, delivery, retry, and rendering actions.

Inputs
  • observed feature traffic
Outputs
  • consumer state map
Evidence gate
One request field and one trigger action are identified.
Negative control
A valid benign URL establishes intended behavior.
Stop condition
Do not infer a fetch from URL acceptance alone.
02

Establish a direct callback

Submit one unique HTTPS listener URL and preserve DNS and HTTP events separately.

Inputs
  • fresh callback token
Outputs
  • raw callback record
Evidence gate
The callback token maps to one request and one field.
Negative control
An unsubmitted token and inert non-URL input remain quiet.
Stop condition
Do not open the token in your own browser.
03

Test one URL component at a time

Compare safe variations that still point only to the controlled listener.

Inputs
  • direct baseline
Outputs
  • accepted parser matrix
Evidence gate
Direct, userinfo, port, scheme, and fragment tokens are unique and independently attributable.
Negative control
The same variation with the URL-sensitive delimiter removed is rejected or quiet.
Stop condition
No loopback, link-local, private, metadata, or third-party destinations.
04

Bound the proven primitive

Report resolution, HTTP request, method, headers, redirects, retries, and triggerability as separate facts.

Inputs
  • callback matrix
Outputs
  • minimal SSRF evidence packet
Evidence gate
The conclusion does not claim internal reachability or response access without proof.
Negative control
Browser and security-scanner explanations are checked.
Stop condition
Stop after sufficient controlled callback evidence.

Continue with the right depth.

References