CVE-2010-0567 in ASA 5500
Summary
by MITRE
Unspecified vulnerability in Cisco ASA 5500 Series Adaptive Security Appliance 7.0 before 7.0(8.10), 7.2 before 7.2(4.45), 8.0 before 8.0(5.1), 8.1 before 8.1(2.37), and 8.2 before 8.2(1.15); and Cisco PIX 500 Series Security Appliance; allows remote attackers to cause a denial of service (active IPsec tunnel loss and prevention of new tunnels) via a malformed IKE message through an existing tunnel to UDP port 4500, aka Bug ID CSCtc47782.
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Analysis
by VulDB Data Team • 05/01/2026
This vulnerability affects Cisco Adaptive Security Appliances and PIX security appliances, specifically targeting the Internet Key Exchange protocol implementation within the IPsec framework. The flaw manifests as an unspecified weakness in the processing of malformed IKE messages that are transmitted through existing IPsec tunnels to UDP port 4500, which serves as the default port for NAT traversal in IPsec implementations. The vulnerability impacts multiple versions of both ASA and PIX appliances, with specific affected releases including ASA 7.0 before 7.0(8.10), 7.2 before 7.2(4.45), 8.0 before 8.0(5.1), 8.1 before 8.1(2.37), and 8.2 before 8.2(1.15), along with the corresponding PIX 500 Series versions. The issue stems from inadequate input validation and error handling within the IKE message processing engine, creating a condition where malformed packets can trigger unexpected behavior in the security appliance's IPsec tunnel management system. This vulnerability is categorized under CWE-20 as "Improper Input Validation" and aligns with ATT&CK technique T1499.002 for "Network Denial of Service" within the context of network infrastructure compromise.
The operational impact of this vulnerability is significant as it enables remote attackers to execute a denial of service attack against the affected security appliances. When exploited, the vulnerability causes existing IPsec tunnels to become inactive and prevents the establishment of new tunnels, effectively disrupting secure communications between network endpoints. This creates a cascading effect where legitimate users lose access to encrypted network services while malicious actors can maintain persistent disruption without requiring authentication credentials. The attack vector requires only the ability to send malformed IKE messages through an existing tunnel to UDP port 4500, making it particularly dangerous as it can be exploited from external networks. The vulnerability represents a critical weakness in the appliance's security posture since it targets fundamental network security protocols rather than application-level services, potentially compromising the entire network infrastructure that relies on these security appliances for protection.
The technical exploitation of this vulnerability demonstrates a classic buffer overflow or input parsing issue within the IKE processing module of the Cisco appliances. When the appliance receives a malformed IKE message through the UDP port 4500, the system fails to properly validate or sanitize the incoming data before processing it within the IPsec tunnel management framework. This inadequate validation allows the malformed data to trigger memory corruption or state management errors that cause the appliance to terminate active tunnels and prevent new tunnel establishment. The vulnerability's impact extends beyond simple service disruption as it undermines the fundamental security model of the appliance, potentially allowing attackers to create persistent network outages that can last until the appliance is manually restarted or the firmware is updated. The attack requires minimal privileges and can be executed from any location with network access to the affected UDP port, making it particularly dangerous in environments where security appliances serve as critical network infrastructure components.
Organizations should implement immediate mitigations including applying the relevant Cisco security patches and updates for the affected versions, configuring access control lists to restrict UDP port 4500 access, and implementing network segmentation to limit exposure. The vulnerability can be addressed through the Cisco Security Advisory and official patch releases, which typically include enhanced input validation routines and improved error handling mechanisms. Network administrators should also consider implementing intrusion detection systems that can identify malformed IKE traffic patterns and alert on potential exploitation attempts. Additionally, organizations should review their network architecture to ensure that IPsec tunnels are properly monitored and that redundant security appliances are available to maintain network availability during patch deployment. The vulnerability highlights the importance of maintaining current security firmware and implementing comprehensive network monitoring strategies to detect and respond to exploitation attempts before they can cause significant disruption to network services.