CVE-2012-4001 in HTTP Server
Summary
by MITRE
The mod_pagespeed module before 0.10.22.6 for the Apache HTTP Server does not properly verify its host name, which allows remote attackers to trigger HTTP requests to arbitrary hosts via unspecified vectors, as demonstrated by requests to intranet servers.
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Analysis
by VulDB Data Team • 04/13/2021
The CVE-2012-4001 vulnerability affects the mod_pagespeed module version 0.10.22.6 and earlier installations within the Apache HTTP Server environment. This security flaw represents a critical host name verification weakness that enables remote attackers to manipulate the module's behavior and initiate unauthorized HTTP requests to arbitrary network hosts. The vulnerability specifically targets the module's failure to properly validate host names during request processing, creating a pathway for attackers to bypass normal network restrictions and access internal systems that would typically be protected from external exposure.
The technical implementation of this vulnerability stems from improper hostname validation mechanisms within the mod_pagespeed module's request handling logic. When the module processes web requests, it fails to adequately verify the authenticity and legitimacy of host names specified in HTTP requests, allowing attackers to craft malicious requests that could force the module to establish connections to internal network resources. This flaw operates through unspecified vectors that likely involve manipulation of request parameters or headers that the module uses to determine target destinations for its optimization processes. The vulnerability's impact extends beyond simple network traversal as it can be exploited to access intranet servers that are normally isolated from external networks, potentially exposing sensitive internal resources to unauthorized access.
The operational consequences of this vulnerability are severe and multifaceted, particularly in enterprise environments where internal network segmentation is critical for security. Attackers can leverage this weakness to perform reconnaissance activities against internal systems, potentially discovering network topology information, identifying running services, and accessing sensitive data stored on intranet servers. The vulnerability's ability to trigger HTTP requests to arbitrary hosts means that attackers can effectively use the compromised Apache server as a proxy to access internal resources that would otherwise be protected by firewalls and network segmentation policies. This creates a significant risk for organizations that rely on internal network isolation as part of their security architecture, as the vulnerability essentially provides a method for bypassing these protective measures.
Security professionals should consider this vulnerability in the context of the CWE-20 standard, which addresses "Improper Input Validation" and specifically relates to the failure to properly validate host names in network communications. The attack vector aligns with techniques described in the ATT&CK framework under the "Command and Control" and "Initial Access" phases, where adversaries establish persistent access through compromised servers. Organizations should implement immediate mitigations including updating to mod_pagespeed version 0.10.22.6 or later, which contains the necessary host name verification fixes. Network segmentation controls should be reviewed and reinforced to minimize the impact of potential exploitation, while monitoring systems should be enhanced to detect unusual HTTP request patterns that might indicate exploitation attempts. Additionally, administrators should consider implementing additional access controls and firewall rules to limit the module's ability to access internal network resources, particularly when the module is configured to perform content optimization tasks that require external connectivity.