Excessive Iteration Affecting openssl package, versions <1:1.1.1k-12.el8_9


Severity

Recommended
low

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.13% (50th percentile)

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  • Snyk IDSNYK-RHEL8-OPENSSL-5812870
  • published1 Aug 2023
  • disclosed31 Jul 2023

Introduced: 31 Jul 2023

CVE-2023-3817  (opens in a new tab)
CWE-834  (opens in a new tab)

How to fix?

Upgrade RHEL:8 openssl to version 1:1.1.1k-12.el8_9 or higher.
This issue was patched in RHSA-2023:7877.

NVD Description

Note: Versions mentioned in the description apply only to the upstream openssl package and not the openssl package as distributed by RHEL. See How to fix? for RHEL: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. After fixing CVE-2023-3446 it was discovered that a large q parameter value can also trigger an overly long computation during some of these checks. A correct q value, if present, cannot be larger than the modulus p parameter, thus it is unnecessary to perform these checks if q is larger than p.

An application that calls DH_check() and supplies a key or parameters obtained from an untrusted source could be vulnerable 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.

CVSS Scores

version 3.1