CVE-2003-1418 in HTTP Server
Summary
by MITRE
Apache HTTP Server 1.3.22 through 1.3.27 on OpenBSD allows remote attackers to obtain sensitive information via (1) the ETag header, which reveals the inode number, or (2) multipart MIME boundary, which reveals child process IDs (PID).
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Analysis
by VulDB Data Team • 07/05/2024
The vulnerability described in CVE-2003-1418 affects Apache HTTP Server versions 1.3.22 through 1.3.27 when deployed on OpenBSD operating systems. This security flaw represents a classic information disclosure vulnerability that exposes system internals to remote attackers. The vulnerability stems from the server's improper handling of certain HTTP response headers and multipart MIME processing, creating opportunities for attackers to gather sensitive system information that could aid in further exploitation attempts.
The technical implementation of this vulnerability manifests in two distinct ways of information leakage. The first vulnerability occurs through the ETag header generation process where the server includes inode numbers in the ETag response header. Inode numbers are internal filesystem identifiers that provide detailed information about file system structure and can reveal system-specific details about the hosting environment. The second vulnerability involves multipart MIME boundary handling where the server reveals child process IDs in the boundary strings used for multipart form data processing. Process IDs are critical system identifiers that can provide insights into running processes and system architecture, potentially enabling attackers to perform process enumeration and system reconnaissance activities.
From an operational impact perspective, this vulnerability creates significant risks for system security and privacy. The exposure of inode numbers through ETag headers can allow attackers to perform file system enumeration and potentially identify specific files or directories that may contain sensitive information. The revelation of child process IDs through multipart boundary strings provides attackers with process-level information that could be leveraged for process-based attacks or to understand the server's operational behavior. These information disclosure vulnerabilities can serve as initial footholds for more sophisticated attacks, particularly when combined with other reconnaissance data gathering techniques. The vulnerability is particularly concerning because it affects a widely deployed web server component and exposes fundamental system identifiers that are typically considered sensitive.
The underlying cause of this vulnerability aligns with CWE-200, which describes improper exposure of sensitive information, and can be categorized under the broader ATT&CK technique T1082 for system information discovery. This vulnerability demonstrates how seemingly minor implementation details in web server response handling can create significant security implications. The exposure of system internals through HTTP headers and boundary strings represents a failure in proper security-conscious programming practices where developers did not adequately consider the potential information leakage from their implementation choices.
Organizations affected by this vulnerability should prioritize immediate patching of their Apache HTTP Server installations to versions that address these information disclosure issues. The recommended mitigation strategy involves upgrading to Apache HTTP Server version 1.3.28 or later, which contains fixes for the ETag header generation and multipart MIME boundary handling. Additionally, system administrators should implement network monitoring to detect unusual patterns in HTTP header analysis and boundary string usage that might indicate exploitation attempts. Security teams should also consider implementing access controls and firewall rules to limit exposure to potentially malicious actors while the patching process is underway, ensuring that the information disclosure does not provide attackers with sufficient data to plan more sophisticated attacks against the affected systems.