openSUSE Security Update : openssl (openSUSE-2016-288) (DROWN)
Critical Nessus Plugin ID 89090
SynopsisThe remote openSUSE host is missing a security update.
DescriptionThis update for openssl fixes the following issues :
Security issues fixed :
- CVE-2016-0800 aka the 'DROWN' attack (bsc#968046):
OpenSSL was vulnerable to a cross-protocol attack that could lead to decryption of TLS sessions by using a server supporting SSLv2 and EXPORT cipher suites as a Bleichenbacher RSA padding oracle.
This update changes the openssl library to :
- Disable SSLv2 protocol support by default.
This can be overridden by setting the environment variable 'OPENSSL_ALLOW_SSL2' or by using SSL_CTX_clear_options using the SSL_OP_NO_SSLv2 flag.
Note that various services and clients had already disabled SSL protocol 2 by default previously.
Please also note that we built the 13.2 openSUSE openssl already with 'no-ssl2'.
- Disable all weak EXPORT ciphers by default. These can be reenabled if required by old legacy software using the environment variable 'OPENSSL_ALLOW_EXPORT'.
- CVE-2016-0702 aka the 'CacheBleed' attack. (bsc#968050) Various changes in the modular exponentation code were added that make sure that it is not possible to recover RSA secret keys by analyzing cache-bank conflicts on the Intel Sandy-Bridge microarchitecture.
Note that this was only exploitable if the malicious code was running on the same hyper threaded Intel Sandy Bridge processor as the victim thread performing decryptions.
- CVE-2016-0705 (bnc#968047): A double free() bug in the DSA ASN1 parser code was fixed that could be abused to facilitate a denial-of-service attack.
- CVE-2016-0797 (bnc#968048): The BN_hex2bn() and BN_dec2bn() functions had a bug that could result in an attempt to de-reference a NULL pointer leading to crashes. This could have security consequences if these functions were ever called by user applications with large untrusted hex/decimal data. Also, internal usage of these functions in OpenSSL uses data from config files or application command line arguments. If user developed applications generated config file data based on untrusted data, then this could have had security consequences as well.
- CVE-2016-0798 (bnc#968265) The SRP user database lookup method SRP_VBASE_get_by_user() had a memory leak that attackers could abuse to facility DoS attacks. To mitigate the issue, the seed handling in SRP_VBASE_get_by_user() was disabled even if the user has configured a seed. Applications are advised to
- We're unaffected by CVE-2016-0799 (boo#968374) because we use glibc's printf implementation instead of the built in one
Bugs fixed :
- avoid running OPENSSL_config twice. This avoids breaking engine loading. (boo#952871)
SolutionUpdate the affected openssl packages.