SynopsisThe remote Debian host is missing a security update.
DescriptionMultiple vulnerabilities have been discovered in OpenSSL, a Secure Sockets Layer toolkit. The Common Vulnerabilities and Exposures project identifies the following issues :
Pieter Wuille of Blockstream reported that the bignum squaring (BN_sqr) may produce incorrect results on some platforms, which might make it easier for remote attackers to defeat cryptographic protection mechanisms.
Markus Stenberg of Cisco Systems, Inc. reported that a carefully crafted DTLS message can cause a segmentation fault in OpenSSL due to a NULL pointer dereference. A remote attacker could use this flaw to mount a denial of service attack.
Karthikeyan Bhargavan of the PROSECCO team at INRIA reported that an OpenSSL client would accept a handshake using an ephemeral ECDH ciphersuite if the server key exchange message is omitted. This allows remote SSL servers to conduct ECDHE-to-ECDH downgrade attacks and trigger a loss of forward secrecy.
Antti Karjalainen and Tuomo Untinen of the Codenomicon CROSS project and Konrad Kraszewski of Google reported various certificate fingerprint issues, which allow remote attackers to defeat a fingerprint-based certificate-blacklist protection mechanism.
Karthikeyan Bhargavan of the PROSECCO team at INRIA reported that an OpenSSL client will accept the use of an ephemeral RSA key in a non-export RSA key exchange ciphersuite, violating the TLS standard.
This allows remote SSL servers to downgrade the security of the session.
NOTE: Tenable Network Security has extracted the preceding description block directly from the DLA security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
SolutionUpgrade the affected packages.