CVE-2007-0962 in Pix Firewall
Summary
by MITRE
Cisco PIX 500 and ASA 5500 Series Security Appliances 7.0 before 7.0(4.14) and 7.1 before 7.1(2.1), and the FWSM 2.x before 2.3(4.12) and 3.x before 3.1(3.24), when "inspect http" is enabled, allows remote attackers to cause a denial of service (device reboot) via malformed HTTP traffic.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 07/14/2019
The vulnerability identified as CVE-2007-0962 represents a critical denial of service flaw affecting Cisco PIX 500 and ASA 5500 Series Security Appliances along with the FWSM 2.x and 3.x platforms. This weakness specifically manifests when the "inspect http" feature is enabled on affected devices, creating a scenario where remote attackers can exploit malformed HTTP traffic to trigger device reboots. The vulnerability impacts multiple software versions including various releases of the 7.0 and 7.1 series for ASA appliances, as well as specific iterations of the FWSM software. This flaw demonstrates the inherent risks associated with protocol inspection mechanisms that fail to properly validate incoming traffic before processing it through security filters. The vulnerability operates at the application layer of network security devices, where HTTP traffic inspection is performed as part of the security appliance's normal operations.
The technical implementation of this vulnerability stems from insufficient input validation within the HTTP inspection module of Cisco's security appliances. When "inspect http" is enabled, the device processes HTTP traffic through a series of validation checks designed to detect and prevent malicious content. However, the flaw occurs when malformed HTTP requests are crafted in such a way that they bypass initial validation stages but cause the inspection engine to crash or enter an unstable state. The malformed traffic typically involves irregularities in HTTP headers, body content, or protocol sequences that when processed by the inspection module result in memory corruption or resource exhaustion. This behavior aligns with CWE-122, which describes buffer overflow conditions, and CWE-400, which covers unspecified resource management errors. The vulnerability's exploitation requires minimal network access and can be executed remotely without authentication, making it particularly dangerous for network security infrastructure.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise network security posture and availability. When an affected security appliance reboots due to this flaw, it creates a window of vulnerability where network traffic flows through the device are either dropped or handled by backup systems that may not provide equivalent security protections. This denial of service condition can be particularly devastating in environments where these appliances serve as primary network gateways or security boundaries, as it effectively removes the security controls for the duration of the device downtime. The vulnerability's impact is amplified by the fact that many organizations deploy these appliances as core components of their network infrastructure, meaning a single exploit can affect large portions of network traffic. From an ATT&CK framework perspective, this vulnerability maps to T1499.004 for Network Denial of Service and T1566.001 for Phishing, as it can be leveraged to disrupt network availability and potentially as part of broader attack campaigns.
Mitigation strategies for CVE-2007-0962 involve immediate software updates to versions that address the HTTP inspection flaw, as well as operational measures to reduce exposure. Organizations should prioritize upgrading to Cisco IOS versions 7.0(4.14) and 7.1(2.1) for ASA appliances, and 2.3(4.12) and 3.1(3.24) for FWSM devices. The patching process requires careful planning due to potential compatibility issues with existing network configurations. In addition to software updates, administrators can implement temporary workarounds such as disabling the "inspect http" command on affected appliances until proper patches are deployed. Network monitoring should be enhanced to detect unusual traffic patterns that might indicate exploitation attempts, while also implementing intrusion detection systems that can identify malformed HTTP traffic. The vulnerability highlights the importance of maintaining current security software versions and demonstrates how seemingly routine protocol inspection features can become attack vectors when insufficiently validated. Organizations should also consider implementing redundant security appliances and ensuring proper network segmentation to limit the impact of such vulnerabilities on overall network availability.