CVE-2007-0187 in FirePass
Summary
by MITRE
F5 FirePass 5.4 through 5.5.2 and 6.0 allows remote attackers to access restricted URLs via (1) a trailing null byte, (2) multiple leading slashes, (3) Unicode encoding, (4) URL-encoded directory traversal or same-directory characters, or (5) upper case letters in the domain name.
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Analysis
by VulDB Data Team • 08/17/2018
The vulnerability identified as CVE-2007-0187 affects F5 FirePass authentication appliances running versions 5.4 through 5.5.2 and 6.0, representing a significant security flaw in web application firewall and authentication systems. This issue stems from improper input validation and URL parsing mechanisms within the FirePass appliance that fails to properly sanitize user-supplied URLs, creating multiple attack vectors for remote exploitation. The vulnerability operates at the application layer and can be classified under CWE-20 as Improper Input Validation, specifically targeting the URL handling components of the authentication system.
The technical exploitation of this vulnerability occurs through several distinct methods that all leverage different aspects of URL parsing and encoding inconsistencies. Attackers can utilize trailing null bytes to bypass access controls by appending null characters to URLs, which may be ignored by the underlying parsing mechanisms. Multiple leading slashes create path traversal scenarios that can circumvent directory restrictions, while Unicode encoding allows attackers to encode characters in ways that evade detection mechanisms. URL-encoded directory traversal sequences and same-directory characters can manipulate the path resolution process, and uppercase letters in domain names can exploit case-insensitive comparisons that may not properly normalize input. These techniques collectively represent variations of path traversal and input manipulation attacks that exploit weaknesses in how the appliance processes and validates URL components.
The operational impact of this vulnerability is severe as it allows remote attackers to bypass authentication and access restricted URLs without proper authorization. This creates a significant risk of unauthorized access to protected resources, potentially leading to data breaches, privilege escalation, and unauthorized system access. The vulnerability affects the core authentication and authorization functionality of the FirePass appliance, which is designed to protect network resources and control access to sensitive applications. Organizations relying on this appliance for security enforcement face potential exposure of critical systems, user credentials, and sensitive data if exploited successfully. The remote nature of the attack means that adversaries can exploit these flaws from external networks without requiring physical access or local privileges.
Mitigation strategies for CVE-2007-0187 should focus on immediate patching and configuration hardening. Organizations must upgrade to patched versions of F5 FirePass appliances that address these URL parsing vulnerabilities. Network administrators should implement additional input validation measures at the appliance level and consider deploying web application firewalls with enhanced URL filtering capabilities. The implementation of strict URL normalization processes, including case normalization, null byte removal, and proper encoding validation, can help prevent exploitation attempts. Security teams should also establish monitoring procedures to detect unusual URL access patterns and implement comprehensive access control policies that limit the impact of potential exploitation. These measures align with ATT&CK techniques related to credential access and privilege escalation, emphasizing the importance of proper input validation and access control enforcement in preventing such vulnerabilities from being exploited in real-world scenarios.