OSSN-0033: Some SSL-Enabled connections fail to perform basic certificate checks

Summary

In many places, OpenStack components use Python 2.x HTTPSConnection to establish an SSL connection between endpoints. This does not provide many of the assurances one would expect when using SSL and leaves connections open to potential man-in-the-middle attacks.

Affected Services / Software

All OpenStack services, Havana, Icehouse, Juno

Discussion

A secure SSL session relies on validation of a X.509 certificate. Basic checks include:

  • Certificate Authority trust verification

  • Certificate revocation status

  • Certificate expiration

  • Certificate subject name matching

The HTTPSConnection class is used in a large number of locations and fails to check that certificates are signed by a valid authority. Without that check in place, the subsequent checks (some highlighted above) are largely invalid.

The result is that an attacker who has access to the network traffic between two endpoints relying on HTTPSConnection can trivially create a certificate that will be accepted by HTTPSConnection as valid - allowing the attacker to intercept, read and modify traffic that should be encrypted by SSL.

Contacts / References

Author: Robert Clark, HP