CVE-2018-0732

Client DoS due to large DH parameter

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).

Category

7.5
CVSS
Severity: High
CVSS 3.1 •
CVSS 2.0 •
EPSS 81.09% Top 5%
Vendor Advisory debian.org Vendor Advisory redhat.com Vendor Advisory gentoo.org Vendor Advisory ubuntu.com Vendor Advisory redhat.com Vendor Advisory redhat.com Vendor Advisory ubuntu.com Vendor Advisory redhat.com Vendor Advisory debian.org Vendor Advisory redhat.com Vendor Advisory redhat.com Vendor Advisory redhat.com Vendor Advisory fedoraproject.org Vendor Advisory fedoraproject.org Vendor Advisory fedoraproject.org Vendor Advisory nodejs.org Vendor Advisory openssl.org
Affected: OpenSSL OpenSSL
Published at:
Updated at:

References

Link Tags
https://lists.debian.org/debian-lts-announce/2018/07/msg00043.html third party advisory mailing list
http://www.securityfocus.com/bid/104442 third party advisory vdb entry
https://www.debian.org/security/2018/dsa-4355 third party advisory vendor advisory
https://access.redhat.com/errata/RHSA-2018:2552 third party advisory vendor advisory
https://security.gentoo.org/glsa/201811-03 third party advisory vendor advisory
https://usn.ubuntu.com/3692-2/ third party advisory vendor advisory
https://access.redhat.com/errata/RHSA-2018:2553 third party advisory vendor advisory
https://access.redhat.com/errata/RHSA-2018:3505 third party advisory vendor advisory
https://usn.ubuntu.com/3692-1/ third party advisory vendor advisory
https://access.redhat.com/errata/RHSA-2018:3221 third party advisory vendor advisory
https://www.debian.org/security/2018/dsa-4348 third party advisory vendor advisory
http://www.securitytracker.com/id/1041090 third party advisory vdb entry
https://access.redhat.com/errata/RHSA-2019:1297 third party advisory vendor advisory
https://access.redhat.com/errata/RHSA-2019:1296 third party advisory vendor advisory
https://access.redhat.com/errata/RHSA-2019:1543 third party advisory vendor advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EWC42UXL5GHTU5G77VKBF6JYUUNGSHOM/ vendor advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZBEV5QGDRFUZDMNECFXUSN5FMYOZDE4V/ vendor advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Y3IVFGSERAZLNJCK35TEM2R4726XIH3Z/ vendor advisory
https://www.oracle.com/security-alerts/cpuapr2020.html third party advisory
http://www.oracle.com/technetwork/security-advisory/cpuoct2018-4428296.html third party advisory patch
https://www.oracle.com/technetwork/security-advisory/cpujan2019-5072801.html third party advisory patch
https://www.oracle.com/technetwork/security-advisory/cpuapr2019-5072813.html third party advisory patch
https://www.oracle.com/technetwork/security-advisory/cpujul2019-5072835.html third party advisory patch
https://www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.html third party advisory patch
https://www.oracle.com/security-alerts/cpujan2021.html third party advisory
https://www.tenable.com/security/tns-2018-14 third party advisory
https://securityadvisories.paloaltonetworks.com/Home/Detail/133 third party advisory
https://www.tenable.com/security/tns-2018-13 third party advisory
https://www.tenable.com/security/tns-2018-17 third party advisory
https://www.tenable.com/security/tns-2018-12 third party advisory
https://security.netapp.com/advisory/ntap-20181105-0001/ third party advisory
https://nodejs.org/en/blog/vulnerability/august-2018-security-releases/ vendor advisory
https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=3984ef0b72831da8b3ece4745cac4f8575b19098
https://www.openssl.org/news/secadv/20180612.txt vendor advisory
https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=ea7abeeabf92b7aca160bdd0208636d4da69f4f4
https://security.netapp.com/advisory/ntap-20190118-0002/ third party advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-419820.pdf third party advisory

Frequently Asked Questions

What is the severity of CVE-2018-0732?
CVE-2018-0732 has been scored as a high severity vulnerability.
How to fix CVE-2018-0732?
To fix CVE-2018-0732, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2018-0732 being actively exploited in the wild?
It is possible that CVE-2018-0732 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~81% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2018-0732?
CVE-2018-0732 affects OpenSSL OpenSSL.
This platform uses data from the NIST NVD, MITRE CVE, MITRE CWE, First.org and CISA KEV but is not endorsed or certified by these entities. CVE is a registred trademark of the MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. CWE is a registred trademark of the MITRE Corporation and the authoritative source of CWE content is MITRE's CWE web site.
© 2025 Under My Watch. All Rights Reserved.