Agent-ready workflow · client
Blind XSS Callback Evidence
Trace a stored field into a delayed renderer and distinguish persistence, HTML rendering, and JavaScript execution with separate callbacks.
Entry contract
Enter with artifacts, leave with evidence.
Use when
- staff-facing field
- support ticket
- admin dashboard
- email renderer
- stored metadata
Prerequisites
- blind XSS permitted by policy
- controlled record
- private OAST listener
MCP retrieval
Agents can search this workflow, retrieve the complete graph, or request one stage through the read-only Vulns.co MCP connector.
Map source and recall
Record the field, object, storage path, recall action, likely viewer, and cleanup method.
Inputs
- controlled record
Outputs
- source-to-sink map
- callback ledger row
- Evidence gate
- The record and field have a unique case ID and known cleanup path.
- Negative control
- A plain marker in a sibling field does not imply the same renderer.
- Stop condition
- Stop if an uncontrolled person is likely to encounter the record.
Prove persistence first
Use an inert marker to observe storage and transformations before any active markup.
Inputs
- plain canary
Outputs
- transformation record
- Evidence gate
- The marker returns through an approved recall path.
- Negative control
- A rejected or encoded marker documents the non-executing path.
- Stop condition
- Do not escalate if the field is not stored or recalled.
Separate render from execution
Use unique no-referrer render and callback-only execution tokens.
Inputs
- render token
- execution token
Outputs
- protocol-labeled callbacks
- Evidence gate
- The execution token is emitted only by the event payload, never the passive image.
- Negative control
- An unsubmitted token and an encoded-event version remain quiet.
- Stop condition
- Never read cookies, storage, forms, DOM, URL, referrer, or credentials.
Triage viewer and report
Distinguish scanner, proxy, server renderer, headless browser, and human browser evidence.
Inputs
- raw callback events
- submission and recall times
Outputs
- bounded evidence packet
- cleanup record
- Evidence gate
- The report labels viewer privilege and identity as observed, inferred, or unknown.
- Negative control
- A repeated fresh token follows the same path while ambient control tokens do not.
- Stop condition
- Remove or neutralize the controlled record after proof.
Related methods
Continue with the right depth.
Sources