Gentoo: openssl timing based attack vulnerability
This update fixes a timing-based attack on CBC cipher suites used in SSL and TLS which OpenSSL was found to be vulnerable to.
Summary
- --------------------------------------------------------------------- GENTOO LINUX SECURITY ANNOUNCEMENT 200302-10 - --------------------------------------------------------------------- DATE : 2003-02-20 17:28 UTC
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From advisory:
"The attack assumes that multiple SSL or TLS connections involve a common fixed plaintext block, such as a password. An active attacker can substitute specifically made-up ciphertext blocks for blocks sent by legitimate SSL/TLS parties and measure the time until a response arrives: SSL/TLS includes data authentication to ensure that such modified ciphertext blocks will be rejected by the peer (and the connection aborted), but the attacker may be able to use timing observations to distinguish between two different error cases, namely block cipher padding errors and MAC verification errors. This is sufficient for an adaptive attack that finally can obtain the complete plaintext block."
Read the full advisory at: openssl
SOLUTION
It is recommended that all Gentoo Linux users who are running dev-libs/openssl upgrade to openssl-0.9.6i or openssl-0.9.7a as follows:
emerge sync emerge -u openssl emerge clean
- --------------------------------------------------------------------- aliz@gentoo.org - GnuPG key is available at - ---------------------------------------------------------------------
Resolution
References
Availability
Concerns
Severity
PACKAGE : openssl
SUMMARY : timing based attack
EXPLOIT : remote
