CVE-2007-0968 in Firewall Services Module
Summary
by MITRE
Unspecified vulnerability in Cisco Firewall Services Module (FWSM) before 2.3(4.7) and 3.x before 3.1(3.1) causes the access control entries (ACE) in an ACL to be improperly evaluated, which allows remote authenticated users to bypass intended certain ACL protections.
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Analysis
by VulDB Data Team • 07/14/2019
The vulnerability identified as CVE-2007-0968 represents a critical flaw in Cisco Firewall Services Module implementations that affects versions prior to 2.3(4.7) and 3.x before 3.1(3.1). This issue resides within the access control list evaluation mechanism of the firewall module, specifically impacting how access control entries are processed and validated. The flaw manifests in the improper evaluation of access control entries within access control lists, creating a scenario where legitimate security policies can be circumvented through careful manipulation of network traffic patterns.
The technical nature of this vulnerability stems from a failure in the ACL processing logic that governs how the FWSM evaluates incoming traffic against configured access control rules. When access control entries are improperly evaluated, the system fails to correctly enforce the intended security policies that administrators have configured to restrict or permit specific network traffic flows. This misevaluation allows authenticated remote attackers to craft packets or traffic patterns that bypass the normal access control mechanisms, effectively rendering portions of the configured ACL protections ineffective.
From an operational perspective, this vulnerability presents a significant risk to network security infrastructure as it enables malicious actors to gain unauthorized access to protected network segments. The impact extends beyond simple privilege escalation to include potential data exfiltration, lateral movement within the network, and compromise of sensitive resources that should be protected by the configured access control lists. Network administrators who rely on FWSM for traffic filtering and access control enforcement face a critical exposure that could allow attackers to bypass security controls without requiring additional privileges beyond basic authentication.
The vulnerability aligns with CWE-284, which addresses improper access control issues, and demonstrates characteristics consistent with privilege escalation vulnerabilities in network security devices. From an attack perspective, this flaw maps to several ATT&CK techniques including T1071.001 for application layer protocol usage and T1566 for social engineering tactics that could be employed to exploit the bypass capabilities. The authentication requirement for exploitation suggests this vulnerability could be leveraged in targeted attacks against network infrastructure where attackers have already gained legitimate credentials.
Organizations should prioritize immediate remediation through the deployment of Cisco's official patches and updates for FWSM versions affected by this vulnerability. Configuration reviews should be conducted to ensure that access control lists are properly structured and that redundant or conflicting rules do not compound the risk. Network segmentation strategies should be enhanced to limit the potential impact of any successful exploitation attempts. Security monitoring should be strengthened to detect anomalous traffic patterns that might indicate exploitation attempts. The vulnerability underscores the importance of maintaining up-to-date security patches and the critical need for comprehensive network access control policy reviews to prevent similar issues from compromising network security posture.