CVE-2018-0732

Description

During key agreement in a TLS handshake using a DH(E) based ciphersuite a malicious server can send a very large prime value to the client. This will cause the client to spend an unreasonably long period of time generating a key for this prime resulting in a hang until the client has finished. This could be exploited in a Denial Of Service attack. Fixed in OpenSSL 1.1.0i-dev (Affected 1.1.0-1.1.0h). Fixed in OpenSSL 1.0.2p-dev (Affected 1.0.2-1.0.2o).

How to fix CVE-2018-0732

To remediate CVE-2018-0732, upgrade the affected package to a fixed version below.

• —upgrade to 2.7.4-r0 or later
• —upgrade to 1.0.2o-r1 or later
• —upgrade to 1.1.1-1 or later
• —upgrade to 1.0.1t-1+deb8u9 or later
• —upgrade to 1.1.0j-1~deb9u1 or later
• —upgrade to 1.0.2q-1~deb9u1 or later

Is CVE-2018-0732 being exploited?

Likely — EPSS is 78.4%, placing CVE-2018-0732 in the top tier of vulnerabilities by exploitation probability. Prioritise patching.

Affected packages (6)

• from 0, < 2.7.4-r0
• from 0, < 1.0.2o-r1
• from 0, < 1.1.1-1
• from 0, < 1.0.1t-1+deb8u9
• from 0, < 1.1.0j-1~deb9u1
• from 0, < 1.0.2q-1~deb9u1

CVSS scores

References (2)

• ADVISORYsecurity.alpinelinux.org/vuln/CVE-2018-0732
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2018-0732