CVE-2021-28681

Pion WebRTC before 3.0.15 didn't properly tear down the DTLS Connection when certificate verification failed. The PeerConnectionState was set to failed, but a user could ignore that and continue to use the PeerConnection. )A WebRTC implementation shouldn't allow the user to continue if verification has failed.)

Pion WebRTC before 3.0.15 didn't properly tear down the DTLS Connection when certificate verification failed. The PeerConnectionState was set to failed, but a user could ignore that and continue to use the PeerConnection. )A WebRTC implementation shouldn't allow the user to continue if verification has failed.)

Pion WebRTC before 3.0.15 didn't properly tear down the DTLS Connection when certificate verification failed. The PeerConnectionState was set to failed, but a user could ignore that and continue to use the PeerConnection. )A WebRTC implementation shouldn't allow the user to continue if verification has failed.)

Impact

Data channel communication was incorrectly allowed with users who have failed DTLS certificate verification.

This attack requires

• Attacker knows the ICE password.
• Only take place during PeerConnection handshake.

This attack can be detected by monitoring PeerConnectionState in all versions of Pion WebRTC.

Patches

Users should upgrade to v3.0.15.

The exact patch is https://github.com/pion/webrtc/commit/545613dcdeb5dedb01cce94175f40bcbe045df2e

Workarounds

Users should listen for when PeerConnectionState changes to PeerConnectionStateFailed. When it enters this state users should not continue using the PeerConnection.

For more information

If you have any questions or comments about this advisory:

• Open an issue in https://github.com/pion/webrtc
• Email us at [email protected]

Thank you to https://github.com/Gaukas for discovering this.

Pion WebRTC before 3.0.15 didn't properly tear down the DTLS Connection when certificate verification failed. The PeerConnectionState was set to failed, but a user could ignore that and continue to use the PeerConnection. )A WebRTC implementation shouldn't allow the user to continue if verification has failed.)

Impact

Data channel communication was incorrectly allowed with users who have failed DTLS certificate verification.

This attack requires

• Attacker knows the ICE password.
• Only take place during PeerConnection handshake.

This attack can be detected by monitoring PeerConnectionState in all versions of Pion WebRTC.

Patches

Users should upgrade to v3.0.15.

The exact patch is https://github.com/pion/webrtc/commit/545613dcdeb5dedb01cce94175f40bcbe045df2e

Workarounds

Users should listen for when PeerConnectionState changes to PeerConnectionStateFailed. When it enters this state users should not continue using the PeerConnection.

For more information

If you have any questions or comments about this advisory:

• Open an issue in https://github.com/pion/webrtc
• Email us at [email protected]

Thank you to https://github.com/Gaukas for discovering this.

Due to improper error handling, DTLS connections were not killed when certificate verification failed, causing users who did not check the connection state to continue to use the connection. This could allow allow an attacker which holds the ICE password, but not a valid certificate, to bypass this restriction.