CVE-2006-6679 in chetcpasswd
Summary
by MITRE
Pedro Lineu Orso chetcpasswd before 2.4 relies on the X-Forwarded-For HTTP header when verifying a client s status on an IP address ACL, which allows remote attackers to gain unauthorized access by spoofing this header.
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Analysis
by VulDB Data Team • 08/12/2018
The vulnerability identified as CVE-2006-6679 affects the chetcpasswd utility version 2.4 and earlier, which is a tool designed for managing user accounts and passwords in certain network environments. This security flaw represents a classic case of trust misplacement where the system incorrectly relies on information provided by clients without proper validation. The utility implements access control mechanisms based on IP address access control lists but fails to properly validate the source of IP address information, creating a significant security gap that can be exploited by malicious actors.
The technical implementation of this vulnerability stems from the utility's improper handling of the X-Forwarded-For HTTP header, which is a standard header used in web applications to identify the original IP address of a client connecting through a proxy or load balancer. When the chetcpasswd utility processes requests, it examines the X-Forwarded-For header to determine whether the requesting IP address is authorized according to the configured access control list. However, this approach is fundamentally flawed because the X-Forwarded-For header can be easily manipulated by any client that has access to the network connection, as it is not inherently authenticated or protected against modification.
This vulnerability directly maps to CWE-284, which describes improper access control, and represents a specific implementation of trust-based access control that fails to properly validate the source of authentication information. The flaw enables attackers to bypass access controls by simply crafting a malicious X-Forwarded-For header value that contains an IP address that is permitted in the ACL. This allows unauthorized access to systems that should be protected by IP-based restrictions, effectively neutralizing the security controls that were intended to protect sensitive user account management functions.
The operational impact of this vulnerability is significant as it allows remote attackers to gain unauthorized access to user account management systems without requiring legitimate credentials or authentication. This creates a pathway for privilege escalation and potential system compromise, especially in environments where chetcpasswd is used to manage critical user accounts and access permissions. The vulnerability is particularly concerning because it can be exploited from any location on the internet, as long as the attacker can establish a connection to the affected service and manipulate HTTP headers in their requests.
Mitigation strategies for this vulnerability should focus on eliminating the reliance on untrusted HTTP headers for access control decisions. The most effective approach involves implementing proper input validation and authentication mechanisms that do not depend on client-provided information for security decisions. System administrators should upgrade to version 2.4 or later of chetcpasswd where this vulnerability has been addressed, and implement additional security controls such as proper network segmentation, firewall rules, and authentication mechanisms that do not rely on HTTP headers for access control decisions. This vulnerability also highlights the importance of following the principle of least privilege and implementing defense-in-depth strategies that do not depend on a single layer of security controls for access validation.