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Vulnerability · Published Apr 25, 2024 · Assigned by openssl

CVE-2023-6237Excessive time spent checking invalid RSA public keys

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 2.3% (higher than 83% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.9Medium
Exploit odds (30 days)2.3%top 16.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Issue summary: Checking excessively long invalid RSA public keys may take a long time. Impact summary: Applications that use the function EVP_PKEY_public_check() to check RSA public keys may experience long delays. Where the key that is being checked has been obtained from an untrusted source this may lead to a Denial of Service. When function EVP_PKEY_public_check() is called on RSA public keys, a computation is done to confirm that the RSA modulus, n, is composite. For valid RSA keys, n is a product of two or more large primes and this computation completes quickly. However, if n is an overly large prime, then this computation would take a long time. An application that calls EVP_PKEY_public_check() and supplies an RSA key obtained from an untrusted source could be vulnerable to a Denial of Service attack. The function EVP_PKEY_public_check() is not called from other OpenSSL functions however it is called from the OpenSSL pkey command line application. For that reason that application is also vulnerable if used with the '-pubin' and '-check' options on untrusted data. The OpenSSL SSL/TLS implementation is not affected by this issue. The OpenSSL 3.0 and 3.1 FIPS providers are affected by this issue.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:9edk2-aarch6420240524-6.el9_5ALSA-2024:9088
AlmaLinux:9edk2-ovmf20240524-6.el9_5ALSA-2024:9088
AlmaLinux:9edk2-tools20240524-6.el9_5ALSA-2024:9088
AlmaLinux:9edk2-tools-doc20240524-6.el9_5ALSA-2024:9088
AlmaLinux:9openssl1:3.0.7-27.el9ALSA-2024:2447
AlmaLinux:9openssl-devel1:3.0.7-27.el9ALSA-2024:2447
AlmaLinux:9openssl-libs1:3.0.7-27.el9ALSA-2024:2447
AlmaLinux:9openssl-perl1:3.0.7-27.el9ALSA-2024:2447
Alpine:v3.20openssl3.1.4-r4ALPINE-CVE-2023-6237
Alpine:v3.21openssl3.1.4-r4ALPINE-CVE-2023-6237
Alpine:v3.22openssl3.1.4-r4ALPINE-CVE-2023-6237
Alpine:v3.23openssl3.1.4-r4ALPINE-CVE-2023-6237
Alpine:v3.24openssl3.1.4-r4ALPINE-CVE-2023-6237
Debian:12openssl3.0.13-1~deb12u1DEBIAN-CVE-2023-6237
Debian:13openssl3.1.5-1DEBIAN-CVE-2023-6237
Debian:14openssl3.1.5-1DEBIAN-CVE-2023-6237
Rocky Linux:9edk20:20240524-6.el9_5.3RLSA-2024:9088
Ubuntu:22.04:LTSedk22022.02-3ubuntu0.22.04.4USN-7894-1
Ubuntu:24.04:LTSedk22024.02-2ubuntu0.6USN-7894-1
Ubuntu:24.04:LTSedk22024.02-2ubuntu0.6UBUNTU-CVE-2023-6237
Ubuntu:22.04:LTSopenssl3.0.2-0ubuntu1.14UBUNTU-CVE-2023-6237
Ubuntu:22.04:LTSopenssl3.0.2-0ubuntu1.14USN-6622-1
Ubuntu:24.04:LTSopenssl3.0.10-1ubuntu4UBUNTU-CVE-2023-6237

Affected products (as reported)

VendorProductVersions
OpenSSL OpenSSL 3.0.0 – before 3.0.133.1.0 – before 3.1.53.2.0 – before 3.2.1

Weakness: CWE-606 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References