Entreprise d'experts en Sécurité Informatique : Audits et conseils en cybersécurité
Entreprise française de cybersécurité depuis 2004
☎ 03 60 47 09 81 - info@securiteinfo.com


CVE-2021-42717

Description

ModSecurity 3.x through 3.0.5 mishandles excessively nested JSON objects. Crafted JSON objects with nesting tens-of-thousands deep could result in the web server being unable to service legitimate requests. Even a moderately large (e.g., 300KB) HTTP request can occupy one of the limited NGINX worker processes for minutes and consume almost all of the available CPU on the machine. Modsecurity 2 is similarly vulnerable: the affected versions include 2.8.0 through 2.9.4.

POC

Reference

- https://www.oracle.com/security-alerts/cpuapr2022.html

Github

- https://github.com/EkamSinghWalia/Detection-and-Mitigation-script-for-CVE-2021-42717

- https://github.com/nomi-sec/PoC-in-GitHub