Inefficient Regular Expression Complexity Affecting openssl-libs package, versions <2:1.1.1k-12.ksplice1.el8_9



    Attack Complexity Low

    Threat Intelligence

    EPSS 0.22% (60th percentile)
Expand this section
5.3 medium
Expand this section
5.3 medium
Expand this section
Red Hat
5.3 medium

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • published 20 Dec 2023
  • disclosed 19 Jul 2023

How to fix?

Upgrade Oracle:8 openssl-libs to version 2:1.1.1k-12.ksplice1.el8_9 or higher.
This issue was patched in ELSA-2024-12056.

NVD Description

Note: Versions mentioned in the description apply only to the upstream openssl-libs package and not the openssl-libs package as distributed by Oracle. See How to fix? for Oracle:8 relevant fixed versions and status.

Issue summary: Checking excessively long DH keys or parameters may be very slow.

Impact summary: Applications that use the functions DH_check(), DH_check_ex() or EVP_PKEY_param_check() to check a DH key or DH parameters may experience long delays. Where the key or parameters that are being checked have been obtained from an untrusted source this may lead to a Denial of Service.

The function DH_check() performs various checks on DH parameters. One of those checks confirms that the modulus ('p' parameter) is not too large. Trying to use a very large modulus is slow and OpenSSL will not normally use a modulus which is over 10,000 bits in length.

However the DH_check() function checks numerous aspects of the key or parameters that have been supplied. Some of those checks use the supplied modulus value even if it has already been found to be too large.

An application that calls DH_check() and supplies a key or parameters obtained from an untrusted source could be vulernable to a Denial of Service attack.

The function DH_check() is itself called by a number of other OpenSSL functions. An application calling any of those other functions may similarly be affected. The other functions affected by this are DH_check_ex() and EVP_PKEY_param_check().

Also vulnerable are the OpenSSL dhparam and pkeyparam command line applications when using the '-check' option.

The OpenSSL SSL/TLS implementation is not affected by this issue. The OpenSSL 3.0 and 3.1 FIPS providers are not affected by this issue.