CVE-2007-0450 in httpd
Summary
by MITRE
Directory traversal vulnerability in Apache HTTP Server and Tomcat 5.x before 5.5.22 and 6.x before 6.0.10, when using certain proxy modules (mod_proxy, mod_rewrite, mod_jk), allows remote attackers to read arbitrary files via a .. (dot dot) sequence with combinations of (1) "/" (slash), (2) "\" (backslash), and (3) URL-encoded backslash (%5C) characters in the URL, which are valid separators in Tomcat but not in Apache.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 01/05/2025
This directory traversal vulnerability affects web servers that utilize proxy modules such as mod_proxy, mod_rewrite, and mod_jk in Apache HTTP Server versions prior to 5.5.22 and 6.x versions prior to 6.0.10. The flaw stems from improper handling of path traversal sequences when these modules process requests containing combinations of forward slashes, backslashes, and URL-encoded backslashes. The vulnerability is particularly dangerous because it leverages the differing path separator handling between Apache and Tomcat environments, where Tomcat accepts backslash characters as valid path separators while Apache does not. This inconsistency creates a window where malicious actors can exploit the proxy modules to bypass normal path validation mechanisms and access arbitrary files on the server filesystem.
The technical implementation of this vulnerability exploits the way these web server modules interpret and process path components during proxy operations. When a request contains sequences using dot dot notation combined with various separator characters, the proxy modules fail to properly normalize or validate the paths before processing them. The attack vector specifically targets the interaction between Apache's path handling and Tomcat's path handling, allowing attackers to craft URLs that appear benign to Apache but are interpreted as directory traversal attempts by Tomcat's backend. This creates a scenario where the proxy module forwards requests that contain path traversal sequences, and the target Tomcat server processes these sequences using its own path resolution rules, potentially leading to unauthorized file access.
The operational impact of this vulnerability extends beyond simple file disclosure, as it can enable attackers to access sensitive configuration files, application source code, and potentially system-level files that should remain protected. The vulnerability affects both Apache HTTP Server and Tomcat environments, making it particularly dangerous in mixed hosting environments where these technologies are used together. Attackers can exploit this vulnerability to read system files such as password hashes, configuration files, or application data that could lead to further compromise of the affected systems. The widespread use of these proxy modules in enterprise environments means that organizations using Apache with Tomcat integration are particularly at risk, as the vulnerability can be exploited through standard HTTP requests without requiring special privileges or authentication.
Organizations should implement immediate mitigations including updating to patched versions of Apache HTTP Server and Tomcat, specifically versions 5.5.22 and 6.0.10 respectively, or applying relevant security patches. Network-level protections such as web application firewalls should be configured to detect and block suspicious path traversal patterns, particularly those involving combinations of forward slashes, backslashes, and URL-encoded characters. Input validation should be strengthened at all proxy module levels to normalize path components and reject potentially dangerous sequences. The vulnerability aligns with CWE-22 directory traversal weakness and maps to ATT&CK technique T1213.002 for data from information repositories, representing a significant risk to system confidentiality and potentially leading to privilege escalation or lateral movement within affected networks. Regular security audits should verify that proxy module configurations properly sanitize input and that path traversal protections are consistently applied across all server components.