CVE-2022-39956 Partial rule set bypass in OWASP ModSecurity Core Rule Set for HTTP multipart requests using character encoding in the Content-Type or Content-Transfer-Encoding header

2022-09-2000:00:00

CWE-863

NCSC.ch

www.cve.org

7.3 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

LOW

Integrity Impact

LOW

Availability Impact

LOW

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

8.9 High

AI Score

Confidence

High

0.005 Low

EPSS

Percentile

75.5%

JSON

The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass for HTTP multipart requests by submitting a payload that uses a character encoding scheme via the Content-Type or the deprecated Content-Transfer-Encoding multipart MIME header fields that will not be decoded and inspected by the web application firewall engine and the rule set. The multipart payload will therefore bypass detection. A vulnerable backend that supports these encoding schemes can potentially be exploited. 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 upgrade to 3.2.2 and 3.3.3 respectively. The mitigation against these vulnerabilities depends on the installation of the latest ModSecurity version (v2.9.6 / v3.0.8).

CNA Affected

[
  {
    "vendor": "OWASP",
    "product": "ModSecurity Core Rule Set",
    "versions": [
      {
        "version": "3.0.x",
        "status": "affected"
      },
      {
        "version": "3.1.x",
        "status": "affected"
      },
      {
        "version": "unspecified",
        "lessThanOrEqual": "3.2.1",
        "status": "affected",
        "versionType": "custom"
      },
      {
        "version": "unspecified",
        "lessThanOrEqual": "3.3.2",
        "status": "affected",
        "versionType": "custom"
      }
    ]
  }
]