CVE-2014-0710 in Firewall Services Module
Summary
by MITRE
Race condition in the cut-through proxy feature in Cisco Firewall Services Module (FWSM) Software 3.x before 3.2(28) and 4.x before 4.1(15) allows remote attackers to cause a denial of service (device reload) via certain matching traffic, aka Bug ID CSCuj16824.
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Analysis
by VulDB Data Team • 06/09/2021
The vulnerability described in CVE-2014-0710 represents a critical race condition affecting Cisco Firewall Services Module FWSM software versions 3.x prior to 3.2(28) and 4.x prior to 4.1(15). This issue specifically impacts the cut-through proxy feature, which is designed to accelerate packet forwarding by bypassing traditional layer three processing. The race condition occurs when the system processes certain types of matching traffic that trigger concurrent operations within the proxy mechanism, creating a timing window where the device's internal state management becomes inconsistent. This flaw enables remote attackers to exploit the system's handling of concurrent traffic flows and specifically target the cut-through proxy functionality to induce system instability.
The technical implementation of this vulnerability stems from improper synchronization mechanisms within the FWSM software's cut-through proxy processing logic. When matching traffic arrives in rapid succession or under specific traffic patterns, the system's internal counters and state variables fail to maintain proper consistency during concurrent access scenarios. This race condition manifests when multiple threads or processes attempt to modify shared resources simultaneously without adequate locking mechanisms. The flaw is classified under CWE-362, which specifically addresses race conditions in software systems where concurrent access to shared resources creates unpredictable behavior. The vulnerability operates at the network security device level, affecting the fundamental packet processing capabilities of the firewall module.
The operational impact of this vulnerability extends beyond simple denial of service, as it can result in complete device reloads that disrupt network connectivity and require manual intervention to restore service. Attackers can exploit this weakness by crafting specific traffic patterns that trigger the race condition, causing the FWSM to crash and automatically reload its operating system. This reload process typically results in temporary network outages that can last several minutes, depending on the device's configuration and recovery procedures. The attack vector is particularly concerning because it requires no authentication credentials and can be executed remotely, making it accessible to any attacker with network access to the affected device. The vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks targeting network infrastructure components.
Mitigation strategies for this vulnerability require immediate software updates to the affected FWSM versions, specifically upgrading to Cisco FWSM Software 3.2(28) or 4.1(15) and later releases. Network administrators should implement traffic filtering rules to limit the types of packets that can trigger the vulnerable cut-through proxy functionality, particularly focusing on reducing concurrent traffic patterns that could expose the race condition. Additionally, organizations should consider disabling the cut-through proxy feature entirely if it is not essential for their network operations, as this eliminates the attack surface entirely. Security monitoring should be enhanced to detect unusual traffic patterns that might indicate exploitation attempts, and regular vulnerability assessments should be conducted to identify other potential race conditions within network security infrastructure. The remediation process must also include comprehensive testing of updated firmware in controlled environments before deployment to production networks to ensure compatibility with existing security policies and configurations.