CVE-2018-0734: Timing attack against DSA
A flaw was found in OpenSSL versions from 1.1.0 through 1.1.0i inclusive, from 1.0.2 through 1.0.2p inclusive and version 1.1.1. The OpenSSL DSA signature algorithm has been shown to be vulnerable to a timing side channel attack. An attacker could use variations in the signing algorithm to recover the private key.
Reference: https://www.openssl.org/news/secadv/20181030.txt
Upstream Patches: https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=43e6a58d4991a451daf4891ff05a48735df871ac https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=8abfe72e8c1de1b95f50aa0d9134803b4d00070f https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=ef11e19d1365eea2b1851e6f540a0bf365d303e7 https://github.com/openssl/openssl/commit/b96bebacfe814deb99fb64a3ed2296d95c573600
Other sources
OpenSSL could allow a remote attacker to obtain sensitive information, caused by a timing side channel attack in the DSA signature algorithm. An attacker could exploit this vulnerability using variations in the signing algorithm to recover the private key.
— IBM
The OpenSSL DSA signature algorithm has been shown to be vulnerable to a timing side channel attack. An attacker could use variations in the signing algorithm to recover the private key. Fixed in OpenSSL 1.1.1a (Affected 1.1.1). Fixed in OpenSSL 1.1.0j (Affected 1.1.0-1.1.0i). Fixed in OpenSSL 1.0.2q (Affected 1.0.2-1.0.2p).
Affected Software
Remediation
Event History
Parent advisories
This vulnerability appears in the following advisories.
Frequently Asked Questions
What is the severity of CVE-2018-0734?
CVE-2018-0734 is classified as a medium severity vulnerability due to its potential for a timing side channel attack on the OpenSSL DSA signature algorithm.
How do I fix CVE-2018-0734?
To mitigate CVE-2018-0734, upgrade OpenSSL to a version that is not vulnerable, such as 1.1.1 or appropriate patched versions indicated by the vendor.
Which versions of OpenSSL are affected by CVE-2018-0734?
CVE-2018-0734 affects OpenSSL versions from 1.1.0 through 1.1.0i inclusive, 1.0.2 through 1.0.2p inclusive, and version 1.1.1.
What types of attacks can exploit CVE-2018-0734?
CVE-2018-0734 can be exploited using timing side channel attacks that could allow an attacker to recover private keys during signature operations.
Is CVE-2018-0734 applicable to all OpenSSL implementations?
CVE-2018-0734 is specifically related to certain versions of OpenSSL and may not apply to other cryptographic implementations.