CVE-2008-3798 in IOS
Summary
by MITRE
Cisco IOS 12.4 allows remote attackers to cause a denial of service (device crash) via a normal, properly formed SSL packet that occurs during termination of an SSL session.
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Analysis
by VulDB Data Team • 05/26/2025
The vulnerability described in CVE-2008-3798 represents a critical denial of service flaw within Cisco IOS version 12.4 that specifically affects SSL session termination processes. This vulnerability demonstrates how seemingly legitimate network traffic can be exploited to disrupt critical network infrastructure, making it particularly dangerous in enterprise environments where network availability is paramount. The flaw manifests when the system processes normal, properly formed SSL packets during the termination phase of an SSL session, causing the affected device to crash and become unavailable to legitimate users.
This technical vulnerability stems from inadequate input validation and error handling within the SSL implementation of Cisco IOS 12.4. When an SSL session is terminated, the system processes specific packet structures that contain valid SSL protocol elements but trigger unexpected behavior in the underlying processing engine. The flaw operates at the network protocol layer, specifically targeting the SSL/TLS handling mechanisms that are fundamental to secure communications on Cisco networking equipment. According to CWE classification, this vulnerability maps to CWE-129, which encompasses improper validation of input boundaries, and CWE-248, which addresses exposure of an exception to an unexpected environment. The vulnerability's nature aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through exploitation of software vulnerabilities.
The operational impact of this vulnerability extends beyond simple service disruption, as it can potentially affect network availability for extended periods while administrators investigate and implement fixes. Network administrators may experience cascading failures if multiple devices are affected simultaneously, particularly in environments where SSL termination is common for web services, email servers, or other applications requiring encrypted communications. The vulnerability's remote exploitability means that attackers can trigger the denial of service condition from external network positions without requiring physical access or elevated privileges, making it particularly attractive for malicious actors seeking to disrupt network operations. Organizations relying on Cisco IOS 12.4 for SSL termination capabilities face significant risk of operational disruption, especially in mission-critical environments where network uptime is essential.
Mitigation strategies for this vulnerability require immediate implementation of Cisco's security advisories and patches, as the flaw affects core networking functionality that cannot be easily bypassed through configuration changes alone. Network administrators should prioritize upgrading affected Cisco IOS versions to patched releases that address the SSL termination handling issues, while implementing network segmentation to limit the potential impact of successful exploitation attempts. The vulnerability also necessitates monitoring for unusual SSL session termination patterns and implementing intrusion detection systems that can identify anomalous packet sequences that may indicate exploitation attempts. Organizations should conduct thorough vulnerability assessments to identify all affected devices and establish incident response procedures specifically addressing SSL-related denial of service conditions. Additionally, implementing redundant network paths and failover mechanisms can help maintain service availability during remediation efforts.