Advisories for Golang/Github.com/Russellhaering/Gosaml2 package

The ValidateEncodedLogoutRequestPOST function in gosaml2 accepts completely unsigned SAML LogoutRequest messages even when SkipSignatureValidation is set to false. When validateElementSignature returns dsig.ErrMissingSignature, the code in decode_logout_request.go:60-62 silently falls through to process the unverified XML element instead of rejecting it. An attacker who can reach the SP's Single Logout endpoint can forge a LogoutRequest for any user, terminating their session without possessing the IdP's signing key.

The AES-CBC decryption path in DecryptBytes() panics on crafted ciphertext whose plaintext is all zero bytes. After decryption, bytes.TrimRight(data, "\x00") empties the slice, then data[len(data)-1] panics with index out of range [-1]. There is no recover() in the library. The panic propagates through ValidateEncodedResponse and kills the goroutine (or the entire process in non-net/http servers). An attacker needs only the SP's public RSA key (published in SAML metadata) to construct …

Impact SAML Service Providers using this library for SAML authentication support are likely susceptible to Denial of Service attacks. A bug in this library enables attackers to craft a deflate-compressed request which will consume significantly more memory during processing than the size of the original request. This may eventually lead to memory exhaustion and the process being killed. Mitigation The maximum compression ratio achievable with deflate is 1032:1, so by …

This affects all versions of package github.com/russellhaering/goxmldsig. There is a crash on nil-pointer dereference caused by sending malformed XML signatures.

The encoding/xml package in Go (all versions) does not correctly preserve the semantics of attribute namespace prefixes during tokenization round-trips, which allows an attacker to craft inputs that behave in conflicting ways during different stages of processing in affected downstream applications.

This affects all versions of package github.com/russellhaering/gosaml2. There is a crash on nil-pointer dereference caused by sending malformed XML signatures.

This advisory duplicates another.

Impact Given a valid SAML Response, an attacker can potentially modify the document, bypassing signature validation in order to pass off the altered document as a signed one. This enables a variety of attacks, including users accessing accounts other than the one to which they authenticated in the identity provider, or full authentication bypass if an external attacker can obtain an expired, signed SAML Response. Patches A patch is available, …