Armeria SAML authentication bypass due to missing validation on unsigned SAML messages

Impact

The SAML implementation provided by armeria-saml currently accepts unsigned SAML messages (assertions, logout requests, etc.) as they are, rather than rejecting them by default. As a result, an attacker can forge a SAML message to authenticate themselves, despite the fact that such an unsigned SAML message should be rejected.

Patches

The vulnerability has been patched in Armeria version 1.27.2. All users who rely on armeria-saml older than version 1.27.2 must upgrade to 1.27.2 or later.

Workarounds

There is no known workaround for this vulnerability.

References

SamlMessageUtil.validateSignature()