CVE-2008-2055 in PIX
Summary
by MITRE
Cisco Adaptive Security Appliance (ASA) and Cisco PIX security appliance 7.1.x before 7.1(2)70, 7.2.x before 7.2(4), and 8.0.x before 8.0(3)10 allows remote attackers to cause a denial of service via a crafted TCP ACK packet to the device interface.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 08/11/2019
The vulnerability identified as CVE-2008-2055 affects Cisco Adaptive Security Appliance (ASA) and Cisco PIX security appliances running specific versions of their software. This issue represents a critical denial of service weakness that can be exploited by remote attackers to disrupt network security services. The affected software versions include 7.1.x prior to 7.1(2)70, 7.2.x prior to 7.2(4), and 8.0.x prior to 8.0(3)10, indicating a widespread impact across multiple release lines of these security devices. The vulnerability specifically targets the handling of TCP acknowledgment packets, which are fundamental components of the TCP protocol used for reliable network communication. This flaw demonstrates the critical importance of proper input validation and state management in network security appliances where malformed packets could potentially crash entire security infrastructure components.
The technical exploitation of this vulnerability occurs when a remote attacker crafts and sends specially formatted TCP ACK packets to the targeted device interface. These crafted packets trigger an improper handling mechanism within the ASA or PIX software that fails to properly process the malformed acknowledgment data. The flaw essentially causes the device to enter an unstable state where it cannot properly handle subsequent network traffic, leading to complete service disruption. The vulnerability operates at the network protocol level, leveraging the fundamental TCP communication mechanisms that these security appliances rely upon for normal operation. This type of vulnerability is classified as a buffer overflow or improper state handling issue that can be categorized under CWE-129, which deals with improper handling of buffer boundaries. The attack vector requires only network access to the affected device interface, making it particularly dangerous as it can be exploited from remote locations without requiring physical access or authentication credentials.
The operational impact of CVE-2008-2055 extends far beyond simple service disruption, as it can completely compromise the security posture of networks relying on these appliances. When exploited successfully, the vulnerability can render the security appliance unusable, effectively removing network protection for the segments it was designed to secure. Organizations may experience extended downtime while administrators work to restore services, potentially leaving networks vulnerable to other attacks during the recovery period. The attack can be particularly devastating in enterprise environments where these appliances serve as primary security gateways, as it can affect thousands of users and systems simultaneously. Network availability is compromised, which can have cascading effects on business operations and compliance requirements, particularly in regulated industries where continuous network availability is mandated. This vulnerability also represents a significant concern from an attacker perspective as it provides a straightforward method for causing widespread disruption without requiring advanced technical skills or privileged access.
The mitigation strategies for this vulnerability primarily involve applying the security patches released by Cisco as part of their regular update cycles. Organizations should immediately upgrade their affected ASA and PIX devices to versions 7.1(2)70, 7.2(4), or 8.0(3)10, respectively, to address the flaw. Network administrators should also implement temporary network segmentation measures to limit the attack surface and monitor for suspicious TCP traffic patterns that might indicate exploitation attempts. Additionally, implementing intrusion detection systems with signature-based detection for this specific vulnerability can help identify and block exploitation attempts. From a defensive standpoint, this vulnerability aligns with ATT&CK technique T1498, which covers denial of service attacks, and demonstrates the importance of maintaining up-to-date security infrastructure to prevent exploitation of known weaknesses. Organizations should also consider implementing network access controls and monitoring to detect anomalous TCP packet behavior that might indicate attempts to exploit this vulnerability, as the attack does not require authentication or complex attack chains to be effective.