Mozilla Firefox and Thunderbird could allow a remote attacker to execute arbitrary code on the system, caused by a use-after-free error in the PK11ImportCert() function when adding NSSCertificate structures. By persuading a victim to visit a specially-crafted Web site, a remote attacker could exploit this vulnerability using unknown attack vectors to execute arbitrary code on the vulnerable system or cause a denial of service.

Mozilla Network Security Services (NSS) before 3.16.2.1, 3.16.x before 3.16.5, and 3.17.x before 3.17.1, as used in Mozilla Firefox before 32.0.3, Mozilla Firefox ESR 24.x before 24.8.1 and 31.x before 31.1.1, Mozilla Thunderbird before 24.8.1 and 31.x before 31.1.2, Mozilla SeaMonkey before 2.29.1, Google Chrome before 37.0.2062.124 on Windows and OS X, and Google Chrome OS before 37.0.2062.120, does not properly parse ASN.1 values in X.509 certificates, which makes it easier for remote attackers to spoof RSA signatures via a crafted certificate, aka a "signature malleability" issue.

A security issue has been reported in NSS, which can be exploited by a malicious user to disclose certain information.

The issue arises due to an error within the "sslDo1stHandshake()" function in lib/ssl/sslsecur.c, which can be exploited to potentially return unencrypted and unauthenticated data from PRRecv. Successful exploitation requires false start to be enabled.

The issue is said to be fixed in NSS 3.15.4.

References: https://bugs.gentoo.org/showbug.cgi?id=498172 https://developer.mozilla.org/en-US/docs/NSS/NSS3.15.4releasenotes

Upstream bug: https://bugzilla.mozilla.org/showbug.cgi?id=919877

Patch: https://bugzilla.mozilla.org/attachment.cgi?id=825813