Incorrect Authorization with specially crafted requests

Envoy, which Pomerium is based on, contains two authorization related vulnerabilities:

• CVE-2021-32777: incorrectly transform a URL containing a #fragment element, causing a mismatch in path-prefix based authorization decisions.
• CVE-2021-32779: incorrectly handle duplicate headers, dropping all but the last. This may lead to incorrect routing or authorization policy decisions.

Impact

With specially crafted requests, incorrect authorization or routing decisions may be made by Pomerium.

Patches

Pomerium v0.14.8 and v0.15.1 contain an upgraded envoy binary with these vulnerabilities patched.

Workarounds

• This issue can only be triggered when using path prefix based policy. Removing any such policies should provide mitigation.

References

envoy GSA CVE-2021-32777
envoy GSA CVE-2021-32779
envoy announcement

For more information

If you have any questions or comments about this advisory:

• Open an issue in pomerium/pomerium
• Email us at [email protected]