Impact A malformed proposed entry of the intoto/v0.0.2 type can cause a panic on a thread within the Rekor process. The thread is recovered so the client receives a 500 error message and service still continues, so the availability impact of this is minimal.

Patches This is fixed in v1.2.0 of Rekor.

Workarounds No

References Discovered by OSS-Fuzz

Summary

/api/v1/index/retrieve supports retrieving a public key via a user-provided URL, allowing attackers to trigger SSRF to arbitrary internal services.

Since the SSRF only can trigger GET requests, the request cannot mutate state. The response from the GET request is not returned to the caller so data exfiltration is not possible. A malicious actor could attempt to probe an internal network through Blind SSRF.

Impact

SSRF to cloud metadata (169.254.169.254) SSRF to internal Kubernetes APIs SSRF to any service accessible from Fulcio's network

Patches

Upgrade to v1.5.0. Note that this is a breaking change to the search API and fully disables lookups by URL. If you require this feature, please reach out and we can discuss alternatives.

Workarounds

Disable the search endpoint with --enableretrieveapi=false.

Summary

Rekor’s cose v0.0.1 entry implementation can panic on attacker-controlled input when canonicalizing a proposed entry with an empty spec.message. validate() returns nil (success) when message is empty, leaving sign1Msg uninitialized, and Canonicalize() later dereferences v.sign1Msg.Payload.

Impact

A malformed proposed entry of the cose/v0.0.1 type can cause a panic on a thread within the Rekor process. The thread is recovered so the client receives a 500 error message and service still continues, so the availability impact of this is minimal.

Patches

Upgrade to v1.5.0

Workarounds

None