microsoft / microsoft/agent-governance-toolkit
policy-engine: manifest_from_url does not re-validate redirect hops or hostnames
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- Dominant language
- Python
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Description
The SSRF guard evaluates the initial URL's canonical host (#3940), but upstream HttpExtendsFetcher follows redirects internally with no hook, so a redirect off the allowlist and hostname-based targets (localhost aliases, *.nip.io, DNS rebinding) are unchecked. Mitigation today is max_manifest_url_redirects = 0. Tracked upstream in responsibleai/agent-control-spec#20.
Found in the group review of the policy-engine retarget (#3939) and deferred from the follow-up (#3940).
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reading the policy-engine manifest_from_url path and the HttpExtendsFetcher redirect behavior. Review how max_manifest_url_redirects is applied, then compare the current checks with responsibleai/agent-control-spec#20. Done means redirect hops and hostname-based targets are re-validated rather than relying on the current zero-redirect mitigation.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- security
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Active
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100