SB2016030106 - Fedora 23 update for openssl

Description

This security bulletin contains information about 4 secuirty vulnerabilities.

1) Double free error (CVE-ID: CVE-2016-0705)

The vulnerability allows a remote unauthenticated attacker to cause DoS condition on the target system.

The weakness exists due to double-free error when parsing DSA private keys. A remote attacker can trigger memory corruption and cause the service to crash.

2) Information disclosure (CVE-ID: CVE-2016-0702)

The vulnerability allows a local attacker to decrypt data passed via encrypted SSL connection.

The vulnerability exists in the MOD_EXP_CTIME_COPY_FROM_PREBUF() function in crypto/bn/bn_exp.c. The application does not properly consider cache-bank access times during modular exponentiation, which makes it easier for local users to discover RSA keys by running a crafted application on the same Intel Sandy Bridge CPU core as a victim and leveraging cache-bank conflicts.

The vulnerability was dubbed "CacheBleed".

3) Buffer overflow (CVE-ID: CVE-2016-0799)

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to fmtstr function in crypto/bio/b_print.c in OpenSSL improperly calculates string lengths. A remote attacker can cause a denial of service (overflow and out-of-bounds read) or possibly have unspecified other impact via a long string.

4) Information disclosure (CVE-ID: CVE-2016-0800)

The vulnerability allows a remote attacker to decrypt sensitive information.

The vulnerability exists due to usage of weak SSLv2 protocol, which requires to send a ServerVerify message before establishing that a client possesses certain plaintext RSA data. A remote attacker can decrypt TLS ciphertext data by leveraging a Bleichenbacher RSA padding oracle.

The vulnerability is dubbed "DROWN" attack.

Remediation

Install update from vendor's website.

References

• https://bodhi.fedoraproject.org/updates/FEDORA-2016-1f15fef6d4