CVE-2023-3817

Vulnerability Description

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 Score

Affected Products

Related Weaknesses (CWE)

References

• https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=6a1eb62c29db6cb5eecMailing ListPatch
• https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=869ad69aadd985c7b8cBroken Link
• https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=9002fd07327a91f35baMailing ListPatch
• https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=91ddeba0f2269b017dcMailing ListPatch
• https://www.openssl.org/news/secadv/20230731.txtVendor Advisory
• http://seclists.org/fulldisclosure/2023/Jul/43
• http://www.openwall.com/lists/oss-security/2023/07/31/1
• http://www.openwall.com/lists/oss-security/2023/09/22/11
• http://www.openwall.com/lists/oss-security/2023/09/22/9
• http://www.openwall.com/lists/oss-security/2023/11/06/2
• https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=6a1eb62c29db6cb5eecMailing ListPatch
• https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=869ad69aadd985c7b8cBroken Link
• https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=9002fd07327a91f35baMailing ListPatch
• https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=91ddeba0f2269b017dcMailing ListPatch
• https://lists.debian.org/debian-lts-announce/2023/08/msg00019.html