#VU5442 Information disclosure in OpenSSL - CVE-2017-3732

Vulnerability identifier: #VU5442

Vulnerability risk: Low

CVSSv4.0: 1.7 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2017-3732

CWE-ID: CWE-310

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
OpenSSL
Server applications / Encryption software

Vendor: OpenSSL Software Foundation

Description

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.

Mitigation
Update OpenSSL to version 1.0.2k or 1.1.0d.

Vulnerable software versions

OpenSSL: 1.0.2j - 1.0.2, 1.1.0c - 1.1.0

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External links
https://www.openssl.org/news/secadv/20170126.txt

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.