QID 150400

Date Published: 2021-12-01

QID 150400: Apache HTTP Server HTTP/2 Method injection (CVE-2021-33193)

The Apache HTTP Server, colloquially called Apache, is a free and open-source cross-platform web server software.

On affected versions of Apache HTTP Server a vulnerability exists due to improper validation of HTTP/2 requests in mod_proxy, where a specially crafted method sent through HTTP/2 will bypass validation and be forwarded by mod_proxy, which can lead to request splitting or cache poisoning.

Affected Versions:
Apache HTTP Server versions from 2.4.17 to 2.4.48.

QID Detection Logic:(Unauthenticated)
This QID sends a HTTP GET request and checks the response headers to confirm if the host is running vulnerable version of Apache HTTP Server.

Successful exploitation of this vulnerability would allow a remote attacker to send specially crafted HTTP/2 requests to the server and smuggle arbitrary HTTP headers.

CVSS V3 rated as High - 7.5 severity.

CVSS V2 rated as Medium - 5 severity.

Solution

Customers are advised to upgrade to the latest version of Apache HTTP Server to remediate this vulnerability. For more information related to this vulnerability please refer to Apache's Security advisory

Vendor References

Apache HTTP Server Security Advisory - httpd.apache.org/security/vulnerabilities_24.html

CVEs related to QID 150400

CVE-2021-33193 |

Software Advisories

Advisory ID	Software	Component	Link
Apache HTTP Server			httpd.apache.org/download.cgi

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