Security Experts:

OpenSSL Patches Four Vulnerabilities

The OpenSSL Project announced on Thursday the availability of OpenSSL versions 1.1.0d and 1.0.2k, which address a total of four low and moderate severity vulnerabilities.

One of the flaws, tracked as CVE-2017-3731, allows an attacker to trigger an out-of-bounds read using a truncated packet and crash an SSL/TLS server or client running on a 32-bit host.

The weakness, reported in mid-November by Google security researcher Robert Swiecki, affects both the 1.1.0 and 1.0.2 branches when certain ciphers are used, specifically the ChaCha20-Poly1305 for version 1.1.0 and RC4-MD5 for 1.0.2.

Both OpenSSL branches are also affected by a carry propagation bug in the x86_64 Montgomery squaring procedure (CVE-2017-3732). A successful attack relying on a carry propagation bug can allow an attacker to recover encryption keys.

However, in this case, the OpenSSL Project said elliptic curve (EC) algorithms are not affected and attacks against RSA and DSA are difficult to carry out.

“Attacks against DH are considered just feasible (although very difficult) because most of the work necessary to deduce information about a private key may be performed offline,” the OpenSSL Project said in its advisory. “The amount of resources required for such an attack would be very significant and likely only accessible to a limited number of attackers. An attacker would additionally need 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.”

The flaw, reported earlier this month by Google’s OSS-Fuzz project, is very similar to CVE-2015-3193, which OpenSSL patched in December 2015.

The third vulnerability, identified as CVE-2017-3730, affects the 1.1.0 branch and it can be exploited in a denial-of-service (DoS) attack. A malicious server that supplies bad parameters for a DHE or ECDHE key exchange can cause the client to crash.

The flaw, reported recently by Guido Vranken, was fixed by OpenSSL developers before knowing that it had security implications.

OpenSSL 1.0.2k also addresses a low severity vulnerability that was patched in the 1.1.0 branch in November.

Currently, the only supported versions of OpenSSL are 1.0.2 and 1.1.0. Version 1.0.1 no longer receives security updates since January 1.

Related: Non-Security OpenSSL Bugs Lead to Serious Vulnerability

Related: OpenSSL Patch for Low Severity Issue Creates Critical Flaw

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.