CVE-2005-2808 in frox
Summary
by MITRE
frox 0.7.16 and 0.7.17 does not properly parse certain Deny ACLs, which might allow attackers to bypass intended restrictions and access blocked hosts.
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Analysis
by VulDB Data Team • 07/11/2018
The vulnerability identified as CVE-2005-2808 affects the frox web proxy software version 0.7.16 and 0.7.17, representing a critical access control flaw that undermines the security mechanisms designed to restrict network access. This issue resides within the Access Control List (ACL) parsing functionality of the frox proxy server, which is commonly deployed in enterprise environments to control and monitor web traffic. The flaw specifically manifests in the improper handling of Deny ACL entries, which are intended to block access to specific hosts or network segments. When attackers exploit this vulnerability, they can bypass the configured restrictions and gain unauthorized access to blocked resources, effectively rendering the access control policies ineffective. The vulnerability stems from inadequate input validation and parsing logic within the ACL processing code, allowing malformed or specially crafted ACL entries to be interpreted incorrectly by the software.
The technical implementation of this vulnerability involves the improper parsing of Deny ACL rules that should prevent access to certain hosts or IP addresses. When the frox proxy processes these ACL entries, it fails to properly validate or sanitize the input parameters, leading to a condition where attackers can manipulate the parsing logic to allow access to resources that should be blocked. This flaw falls under the category of access control bypass vulnerabilities and can be classified as a CWE-284 Access Control Bypass, which occurs when the software does not properly enforce access restrictions. The vulnerability represents a significant weakness in the software's security architecture, as it allows malicious actors to circumvent network security policies that are fundamental to protecting enterprise resources from unauthorized access. The improper parsing behavior creates a path for privilege escalation and unauthorized data access that can be exploited remotely without requiring authentication or special privileges.
From an operational perspective, this vulnerability poses severe risks to organizations relying on frox for web proxy services, as it fundamentally compromises the security controls designed to protect against unauthorized access to sensitive network resources. Attackers who successfully exploit this vulnerability can access blocked hosts, potentially gaining access to internal networks, sensitive databases, or restricted web applications that should be protected by the proxy's access control policies. The impact extends beyond simple unauthorized access, as this vulnerability can enable more sophisticated attacks including lateral movement within the network, data exfiltration, or the establishment of command and control channels. Organizations using vulnerable versions of frox may experience security breaches where attackers bypass firewalls and network segmentation policies, undermining the entire security infrastructure that relies on proper access control enforcement. The vulnerability is particularly dangerous because it operates at the network access control level, meaning that once exploited, it can allow attackers to move freely within the protected network environment.
The recommended mitigation strategy for CVE-2005-2808 involves immediate upgrading to a patched version of the frox software, as this vulnerability was addressed in subsequent releases. Organizations should also implement network segmentation and additional monitoring controls to detect potential exploitation attempts, as the vulnerability can be used to bypass traditional security measures. Security administrators should conduct thorough audits of their access control policies and verify that all ACL entries are properly configured and validated. Additionally, implementing intrusion detection systems and network monitoring tools can help detect suspicious traffic patterns that may indicate exploitation attempts. The vulnerability demonstrates the critical importance of proper input validation and access control implementation in network security software, as even seemingly minor parsing flaws can result in significant security breaches. Organizations should also consider implementing the principle of least privilege and additional security layers beyond simple ACL-based access control to provide defense-in-depth against such vulnerabilities. This issue aligns with ATT&CK technique T1071.004 Application Layer Protocol: DNS, where attackers may leverage access control bypasses to establish persistent access to network resources.