OpenSSL swats a dozen bugs, one notable nasty
Denial of service dross dead.
A dozen flaws have been patched in OpenSSL, including one high severity hole that allows denial of service attacks.
The OpenSSL Project pushed patches in versions 1.1.0a, 1.0.2i and 1.0.1u, with most of the flaws flagged as low severity risks.
The nastiest vulnerability (CVE-2016-6304) results when attackers issue a massive OCSP status request extension which exhausts memory on servers in default configuration. Researcher Shi Lei of vulnerability blitzkrieg house Qihoo 360 spotted that one.
Admins can mitigate damage by running
no-ocsp or by running older versions of OpenSSL below 1.0.1g.
Another moderate severity denial of service flaw (CVE-2016-6305) is fixed in the patch run which affects 1.0 of OpenSSL.
The OpenSSL project nixed risky ciphers in version 1.1 to squash the so-called Sweet32 exploit which is a birthday attack against 64-bit ciphers like Blowfish and Triple DES.
Cisco said it was difficult to exploit.
“For a successful attack, a large amount of data has to be sent one-way during the session, and the session has to be encrypted using the same key," Borg security engineers said.
"For 64-bit ciphers, it would take about 32GB of data in order to have a 50 percent probability of collision in any of the cipher blocks”. ®