MGASA-2015-0246

A vulnerability in the TLS protocol allows a man-in-the-middle attacker to downgrade vulnerable TLS connections using ephemeral Diffie-Hellman key exchange to 512-bit export-grade cryptography. This vulnerability is known as Logjam (CVE-2015-4000).

When processing an ECParameters structure OpenSSL enters an infinite loop if the curve specified is over a specially malformed binary polynomial field. This can be used to perform denial of service against any system which processes public keys, certificate requests or certificates. This includes TLS clients and TLS servers with client authentication enabled (CVE-2015-1788).

X509cmptime does not properly check the length of the ASN1TIME string and can read a few bytes out of bounds. In addition, X509cmp_time accepts an arbitrary number of fractional seconds in the time string. An attacker can use this to craft malformed certificates and CRLs of various sizes and potentially cause a segmentation fault, resulting in a DoS on applications that verify certificates or CRLs. TLS clients that verify CRLs are affected. TLS clients and servers with client authentication enabled may be affected if they use custom verification callbacks (CVE-2015-1789).

The PKCS#7 parsing code does not handle missing inner EncryptedContent correctly. An attacker can craft malformed ASN.1-encoded PKCS#7 blobs with missing content and trigger a NULL pointer dereference on parsing (CVE-2015-1790).

If a NewSessionTicket is received by a multi-threaded client when attempting to reuse a previous ticket then a race condition can occur potentially leading to a double free of the ticket data (CVE-2015-1791).

When verifying a signedData message the CMS code can enter an infinite loop if presented with an unknown hash function OID. This can be used to perform denial of service against any system which verifies signedData messages using the CMS code (CVE-2015-1792).