CVE-2023-5678
Vulnérabilité moyenne dans OpenSSL (OpenSSL)
Description
Issue summary: Generating excessively long X9.42 DH keys or checking excessively long X9.42 DH keys or parameters may be very slow. Impact summary: Applications that use the functions DH_generate_key() to generate an X9.42 DH key may experience long delays. Likewise, applications that use DH_check_pub_key(), DH_check_pub_key_ex() or EVP_PKEY_public_check() to check an X9.42 DH key or X9.42 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. While DH_check() performs all the necessary checks (as of CVE-2023-3817), DH_check_pub_key() doesn't make any of these checks, and is therefore vulnerable for excessively large P and Q parameters. Likewise, while DH_generate_key() performs a check for an excessively large P, it doesn't check for an excessively large Q. An application that calls DH_generate_key() or DH_check_pub_key() and supplies a key or parameters obtained from an untrusted source could be vulnerable to a Denial of Service attack. DH_generate_key() and DH_check_pub_key() are also 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_pub_key_ex(), EVP_PKEY_public_check(), and EVP_PKEY_generate(). Also vulnerable are the OpenSSL pkey command line application when using the "-pubcheck" option, as well as the OpenSSL genpkey command line application. 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.
Gravité et risque d'exploitation
CVE-2023-5678 obtient un score CVSS de 5.3/10, soit une gravité moyenne. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 4.46 %, ce qui la place devant 91.3 % des CVE référencées.
Que faire ?
- Vérifiez si OpenSSL (versions 3.0.0, 1.1.1, <1.0.2zj, 1.0.2, <3.1.5, <1.1.1x, <3.0.13, 3.1.0) est présent sur votre parc.
- Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
- À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
- Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.
Références
- https://www.openssl.org/news/secadv/20231106.txt
- https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=34efaef6c103d636ab507a0cc34dca4d3aecc055
- https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=710fee740904b6290fef0dd5536fbcedbc38ff0c
- https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=db925ae2e65d0d925adef429afc37f75bd1c2017
- https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=ddeb4b6c6d527e54ce9a99cba785c0f7776e54b6
