OpenSSL: SSL 2.0 protocol rollback — GLSA 200510-11

When using a specific option, OpenSSL can be forced to fallback to the less secure SSL 2.0 protocol.

Affected Packages

dev-libs/openssl on all architectures
Affected versions < 0.9.7h
Unaffected versions >= 0.9.7h, revision >= 0.9.7g-r1, revision >= 0.9.7e-r2

Background

OpenSSL is a toolkit implementing the Secure Sockets Layer, Transport Layer Security protocols and a general-purpose cryptography library.

Description

Applications setting the SSL_OP_MSIE_SSLV2_RSA_PADDING option (or the SSL_OP_ALL option, that implies it) can be forced by a third-party to fallback to the less secure SSL 2.0 protocol, even if both parties support the more secure SSL 3.0 or TLS 1.0 protocols.

Impact

A man-in-the-middle attacker can weaken the encryption used to communicate between two parties, potentially revealing sensitive information.

Workaround

If possible, disable the use of SSL 2.0 in all OpenSSL-enabled applications.

Resolution

All OpenSSL users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose dev-libs/openssl

References

Release Date
October 12, 2005

Latest Revision
November 07, 2005: 02

Severity
low

Exploitable
remote

Bugzilla entries