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

An attacker, opening a HTTP/2 connection with an initial window size of 0, was able to block handling of that connection indefinitely in Apache HTTP Server. This could be used to exhaust worker resources in the server, similar to the well known "slow loris" attack pattern. This has been fixed in version 2.4.58, so that such connection are terminated properly after the configured connection timeout.

This issue affects Apache HTTP Server: from 2.4.55 through 2.4.57.

Users are recommended to upgrade to version 2.4.58, which fixes the issue.

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

Collectors

NVD DatabaseMitre Database

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)
.