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OpenSSL: SSL 2.0 protocol rollback


1.  Gentoo Linux Security Advisory

Version Information

Advisory Reference GLSA 200510-11 / OpenSSL
Release Date October 12, 2005
Latest Revision November 07, 2005: 02
Impact low
Exploitable remote
Package Vulnerable versions Unaffected versions Architecture(s)
dev-libs/openssl < 0.9.7h >= 0.9.7h, revision >= 0.9.7g-r1, revision >= 0.9.7e-r2 All supported architectures

Related bugreports: #108852


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

2.  Impact Information


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


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.


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

3.  Resolution Information


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


All OpenSSL users should upgrade to the latest version:

Code Listing 3.1: Resolution

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

4.  References


Page updated October 12, 2005

Summary: This is a Gentoo Linux Security Advisory

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