Vigil@nce - OpenSAML Java: incomplete certificate validation
October 2015 by Vigil@nce
This bulletin was written by Vigil@nce : http://vigilance.fr/offer
SYNTHESIS OF THE VULNERABILITY
An attacker can use any valid certificate on a malicious server,
and then invite an Apache HttpClient 3 to connect there, in order
to spy communications even if encryption is used.
Impacted products: Fedora, OpenSAML-J.
Severity: 2/4.
Creation date: 07/08/2015.
DESCRIPTION OF THE VULNERABILITY
The OpenSAML Java library can manage HTTP connections over SSL,
using Apache HttpClient 3 (VIGILANCE-VUL-12182).
In order to authenticate a server, the client must check the
certificate (cryptographic signatures, validity date range, etc.)
and also that the received certificate matches the visited server.
This check is usually done on DNS names, or sometimes on IP
addresses. However, HttpClient does not check that the names
included in the certificates match the one requested at HTTP
level. So, any valid certificate is accepted.
An attacker can therefore use any valid certificate on a malicious
server, and then invite an OpenSAML Java to connect there, in
order to spy communications even if encryption is used.
ACCESS TO THE COMPLETE VIGIL@NCE BULLETIN
http://vigilance.fr/vulnerability/OpenSAML-Java-incomplete-certificate-validation-17608