#VU5440 NULL pointer dereference in OpenSSL - CVE-2017-3730

Vulnerability identifier: #VU5440

Vulnerability risk: Low

CVSSv4.0: 2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2017-3730

CWE-ID: CWE-476

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
OpenSSL
Server applications / Encryption software

Vendor: OpenSSL Software Foundation

Description

The vulnerability allows a remote attacker to cause denial of service.

The vulnerability exists in OpenSSL due to NULL pointer dereference error when processing specially crafted parameters for a Diffie-Hellman Key Exchange (DHE) or Elliptic Curve Diffie-Hellman Exchange (ECDHE), received from malicious server. A remote attacker can trick the victim into connecting to a specially crafted website and trigger NULL pointer dereference error in client software.

Successful exploitation of the vulnerability may allow an attacker to perform denial of service (DoS) attack against vulnerable client software.

Mitigation
Update OpenSSL to version 1.1.0d.

Vulnerable software versions

OpenSSL: 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. However, proof of concept for this vulnerability is available.