SB2017121605 - SUSE Linux update for openssl

Description

This security bulletin contains information about 6 secuirty vulnerabilities.

1) Improper input validation (CVE-ID: CVE-2017-3737)

The vulnerability allows a remote attacker to gain access to potentially sensitive information on the target system.

The weakness exists due to an "error state mechanism" when SSL_read() or SSL_write() is called directly after SSL object. A remote attacker can a specially crafted input, trigger a fatal error during a handshake and return it in the initial function call to access or modify sensitive information.

2) Buffer overflow (CVE-ID: CVE-2017-3738)

The vulnerability allows a remote attacker to obtain potentially sensitive information on the target system.

The weakness exists due to buffer overflow in the AVX2 Montgomery multiplication procedure used in exponentiation with 1024-bit moduli. A remote attacker can cause the server to share the DH1024 private key among multiple clients and perform attack on TLS.

3) Information disclosure (CVE-ID: CVE-2016-0701)

The vulnerability allows a remote attacker to obtain potentially sensitive information.

The vulnerability exists due to DH_check_pub_key() function in crypto/dh/dh_check.c in OpenSSL 1.0.2 before 1.0.2f does not ensure that prime numbers are appropriate for Diffie-Hellman (DH) key exchange, which makes it easier for remote attackers to discover a private DH exponent by making multiple handshakes with a peer that chose an inappropriate number, as demonstrated by a number in an X9.42 file.

4) Carry propagation issue (CVE-ID: CVE-2017-3736)

The vulnerability allows a remote attacker to decrypt data.

The vulnerability exists due to carry propagating bug in the x86_64 Montgomery squaring procedure (bn_sqrx8x_internal). A remote attacker can decrypt encrypted data. The vulnerability affects processors that support the BMI1, BMI2 and ADX extensions like Intel Broadwell (5th generation) and later or AMD Ryzen.

5) Information disclosure (CVE-ID: CVE-2017-3732)

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to propagating error in the x86_64 Montgomery squaring procedure. A remote attacker with access to unpatched vulnerable system that uses a shared private key with Diffie-Hellman (DH) parameters set can gain unauthorized access to sensitive private key information.

According to vendor’s advisory, this vulnerability is unlikely to be exploited in real-world attacks, as it requires significant resources and online access to an unpatched system using the target private key in a scenario with persistent DH parameters and a private key that is shared between multiple clients.

Vulnerability exploitation against RSA and DSA as a result of this defect would be very difficult to perform and are not believed likely.

6) Information disclosure (CVE-ID: CVE-2015-3193)

The vulnerability allows a remote attacker to obtain potentially sensitive information on the target system.

The weakness exists in the Montgomery squaring implementation in crypto/bn/asm/x86_64-mont5.pl on the x86_64 platform, as used by the BN_mod_exp function, due to mishandling of carry propagation and producing incorrect output. A remote attacker can gain potentially sensitive private-key information via an attack against use of a (1) Diffie-Hellman (DH) or (2) Diffie-Hellman Ephemeral (DHE) ciphersuite.

Remediation

Install update from vendor's website.

References

• https://lists.opensuse.org/opensuse-security-announce/2017-12/msg00074.html