Apache HTTP Server: DoS in HTTP/2 with initial windows size 0
CVE-2023-43622

7.5HIGH

Key Information:

Vendor
Apache
Status
Apache Http Server
Vendor
CVE Published:
23 October 2023

Summary

A vulnerability in Apache HTTP Server allows an attacker to create an HTTP/2 connection with an initial window size of 0, leading to indefinite blocking of connection handling. This can exhaust server worker resources, resembling the characteristics of a 'slow loris' attack. The issue impacts versions between 2.4.55 and 2.4.57 and has been addressed in version 2.4.58, which ensures proper termination of such connections after the defined timeout. It is highly recommended for users to update to the latest version to mitigate this risk.

Affected Version(s)

Apache HTTP Server 2.4.55 <= 2.4.57

References

https://httpd.apache.org/security/vulnerabilities_24.html
vendor-advisory
https://security.netapp.com/advisory/ntap-20231027-0011/

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Prof. Sven Dietrich (City University of New York)
Isa Jafarov (City University of New York)
Prof. Heejo Lee (Korea University)
Choongin Lee (Korea University)
.