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Vulnerability · Published Jan 28, 2022 · Assigned by openssl

CVE-2021-4160BN_mod_exp may produce incorrect results on MIPS

Medium 5.9

In plain English

A medium-severity security flaw in OpenSSL from OpenSSL. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 3.8% (higher than 90% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)5.9Medium
Exploit odds (30 days)3.8%top 10.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

There is a carry propagation bug in the MIPS32 and MIPS64 squaring procedure. Many EC algorithms are affected, including some of the TLS 1.3 default curves. Impact was not analyzed in detail, because the pre-requisites for attack are considered unlikely and include reusing private keys. Analysis suggests that attacks against RSA and DSA as a result of this defect would be very difficult to perform and are not believed likely. Attacks against DH are considered just feasible (although very difficult) because most of the work necessary to deduce information about a private key may be performed offline. The amount of resources required for such an attack would be significant. However, for an attack on TLS to be meaningful, the server would have to share the DH private key among multiple clients, which is no longer an option since CVE-2016-0701. This issue affects OpenSSL versions 1.0.2, 1.1.1 and 3.0.0. It was addressed in the releases of 1.1.1m and 3.0.1 on the 15th of December 2021. For the 1.0.2 release it is addressed in git commit 6fc1aaaf3 that is available to premium support customers only. It will be made available in 1.0.2zc when it is released. The issue only affects OpenSSL on MIPS platforms. Fixed in OpenSSL 3.0.1 (Affected 3.0.0). Fixed in OpenSSL 1.1.1m (Affected 1.1.1-1.1.1l). Fixed in OpenSSL 1.0.2zc-dev (Affected 1.0.2-1.0.2zb).

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12openssl1.1.1m-1DEBIAN-CVE-2021-4160
Debian:13openssl1.1.1m-1DEBIAN-CVE-2021-4160
Debian:14openssl1.1.1m-1DEBIAN-CVE-2021-4160

Affected products (as reported)

VendorProductVersions
OpenSSL OpenSSL Fixed in OpenSSL 3.0.1 (Affected 3.0.0)Fixed in OpenSSL 1.1.1m (Affected 1.1.1-1.1.1l)Fixed in OpenSSL 1.0.2zc-dev (Affected 1.0.2-1.0.2zb)

References