Vigil@nce - Redhat OpenSSL: denial of service via locking management
July 2015 by Vigil@nce
This bulletin was written by Vigil@nce : http://vigilance.fr/offer
SYNTHESIS OF THE VULNERABILITY
An attacker can repeatedly connect to a TLS multithread server
using the Redhat version of OpenSSL, in order to trigger a denial
of service.
Impacted products: Fedora, openSUSE, RHEL, SUSE Linux Enterprise
Desktop, SLES
Severity: 1/4
Creation date: 16/06/2015
DESCRIPTION OF THE VULNERABILITY
RedHat modified the upstream OpnSSL code for packaging. It
includes a change about locking in multithread applications in the
pseudo random number generator.
However, this locking is not suitably done and there are thread
interleaving that will allow 2 threads entering in the same
critical section, which will lead to the corruption of a pointer
and then to a fatal exception of kind SIGSEGV.
An attacker can therefore repeatedly connect to a TLS multithread
server using the Redhat version of OpenSSL, in order to trigger a
denial of service.
ACCESS TO THE COMPLETE VIGIL@NCE BULLETIN
http://vigilance.fr/vulnerability/Redhat-OpenSSL-denial-of-service-via-locking-management-17147