CVE-2006-2222 in zawhttpd
Summary
by MITRE
Buffer overflow in zawhttpd 0.8.23, and possibly previous versions, allows remote attackers to cause a denial of service (daemon crash) via a request for a URI composed of several "\" (backslash) characters.
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Analysis
by VulDB Data Team • 01/27/2025
The vulnerability identified as CVE-2006-2222 represents a critical buffer overflow flaw affecting the zawhttpd web server version 0.8.23 and potentially earlier releases. This issue resides within the HTTP daemon's handling of Uniform Resource Identifier requests, specifically when processing URIs containing multiple backslash characters. The flaw demonstrates characteristics consistent with CWE-121, which encompasses classic buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The vulnerability operates through a straightforward yet effective attack vector that leverages the server's insufficient input validation mechanisms to trigger memory corruption during request processing.
The technical exploitation of this vulnerability occurs when a remote attacker crafts a malicious HTTP request containing a URI composed entirely of backslash characters. The zawhttpd daemon fails to properly validate the length or composition of incoming URI paths, leading to a situation where the buffer allocated for storing the URI data becomes overflowed when the number of backslashes exceeds the allocated memory space. This overflow condition causes the daemon process to crash and terminate unexpectedly, resulting in a denial of service condition that disrupts legitimate service availability. The attack requires no authentication or specialized privileges, making it particularly dangerous as it can be executed by any remote user capable of sending HTTP requests to the vulnerable server.
The operational impact of CVE-2006-2222 extends beyond simple service disruption to encompass potential system stability concerns and availability risks for organizations relying on affected web server implementations. When the zawhttpd daemon crashes due to this buffer overflow, legitimate users experience complete service interruption until the daemon is manually restarted or the system reboots. This vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through exploitation of software vulnerabilities. Organizations using this particular web server implementation face significant risk of service degradation, especially in environments where continuous availability is critical. The vulnerability also demonstrates the importance of proper input sanitization and memory management practices in network services, as the flaw exists in fundamental request handling code that should have been protected against such overflow conditions.
Mitigation strategies for this vulnerability should focus on immediate patching of the zawhttpd software to versions that address the buffer overflow condition through proper input validation and bounds checking. System administrators should implement network monitoring to detect and alert on unusual request patterns that might indicate exploitation attempts, particularly those involving excessive backslash characters in URI paths. The implementation of web application firewalls or intrusion prevention systems can provide additional protection by filtering malicious requests before they reach the vulnerable daemon. Organizations should also consider implementing redundant service architectures and automated failover mechanisms to minimize the impact of such denial of service conditions. Regular security assessments and vulnerability scanning should be conducted to identify similar buffer overflow vulnerabilities in other network services, as this class of flaw remains prevalent in legacy software implementations. The vulnerability serves as a reminder of the critical importance of input validation and memory safety practices in network service development, aligning with industry best practices for secure coding and defense-in-depth strategies.