stunnel: Security bypass

stunnel: Security bypass stunnel does not properly prevent the authentication of a revoked certificate which would be published by OCSP. stunnel 2008-08-08 2009-08-09 222805 remote 4.24 4 4.24

The stunnel program is designed to work as an SSL encryption wrapper between a remote client and a local or remote server. OCSP (Online Certificate Status Protocol), as described in RFC 2560, is an internet protocol used for obtaining the revocation status of an X.509 digital certificate.

An unspecified bug in the OCSP search functionality of stunnel has been discovered.

A remote attacker can use a revoked certificate that would be successfully authenticated by stunnel. This issue only concerns the users who have enabled the OCSP validation in stunnel.

There is no known workaround at this time.

All stunnel users should upgrade to the latest version:


    # emerge --sync
    # emerge --ask --oneshot --verbose ">=net-misc/stunnel-4.24"

CVE-2008-2420 rbu falco falco