The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass by submitting a specially crafted HTTP Content-Type header field that indicates multiple character encoding schemes. A vulnerable back-end can potentially be exploited by declaring multiple Content-Type charset names and therefore bypassing the configurable CRS Content-Type header charset allow list. An encoded payload can bypass CRS detection this way and may then be decoded by the backend. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised to upgrade to 3.2.2 and 3.3.3 respectively.
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. This allows attackers to bypass intended access restrictions.
Name | Vendor | Start Version | End Version |
---|---|---|---|
Owasp_modsecurity_core_rule_set | Owasp | 3.0.0 (including) | 3.2.2 (excluding) |
Owasp_modsecurity_core_rule_set | Owasp | 3.3.0 (including) | 3.3.3 (excluding) |
Modsecurity-crs | Ubuntu | bionic | * |
Modsecurity-crs | Ubuntu | kinetic | * |
Modsecurity-crs | Ubuntu | lunar | * |
Modsecurity-crs | Ubuntu | mantic | * |
Modsecurity-crs | Ubuntu | trusty | * |
Modsecurity-crs | Ubuntu | xenial | * |
Assuming a user with a given identity, authorization is the process of determining whether that user can access a given resource, based on the user’s privileges and any permissions or other access-control specifications that apply to the resource. When access control checks are incorrectly applied, users are able to access data or perform actions that they should not be allowed to perform. This can lead to a wide range of problems, including information exposures, denial of service, and arbitrary code execution.