Security Advisory (MDKSA-2003:035): openssl

aru · March 25, 2003

MandrakeSoft Security Advisory MDKSA-2003:035 : openssl

March 25th, 2003

Updated openssl packages fix RSA-related insecurities

Researchers discovered a timing-based attack on RSA keys that OpenSSL is generally vulnerable to, unless RSA blinding is enabled. Patches from the OpenSSL team have been applied to turn RSA blinding on by default.

An extension of the "Bleichenbacher attack" on RSA with PKS #1 v1.5 padding as used in SSL 3.0 and TSL 1.0 was also created by Czech cryptologists Vlastimil Klima, Ondrej Pokorny, and Tomas Rosa. This attack requires the attacker to open millions of SSL/TLS connections to the server they are attacking. This is done because the server's behaviour when faced with specially crafted RSA ciphertexts can reveal information that would in effect allow the attacker to perform a single RSA private key operation on a ciphertext of their choice, using the server's RSA key. Despite this, the server's RSA key is not compromised at any time. Patches from the OpenSSL team modify SSL/TLS server behaviour to avoid this vulnerability.

The released versions of Mandrake GNU/Linux affected are: