#VU13325 Improper input validation in OpenSSL - CVE-2018-0732

Vulnerability identifier: #VU13325

Vulnerability risk: Low

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2018-0732

CWE-ID: CWE-20

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 cause DoS condition on the target system.

The vulnerability exists due to improper handling of large prime values by the affected software during key agreement operations in a Transport Layer Security (TLS) handshake using an Ephemeral Diffie-Hellman (DHE) based cipher suite. A remote attacker can send a large prime value from a malicious OpenSSL server to a targeted OpenSSL client and cause the client to stop responding while generating a key for the prime value.

Mitigation
Update to versions 1.1.0i or 1.0.2p.

Vulnerable software versions

OpenSSL: 1.0.2h - 1.0.2, 1.1.0g - 1.1.0

---

External links
https://www.openssl.org/news/secadv/20180612.txt

---

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.