CVE-2013-5568 in ASA
Summary
by MITRE
The auto-update implementation in Cisco Adaptive Security Appliance (ASA) Software 9.0.3.6 and earlier allows remote attackers to cause a denial of service (device reload) via crafted update data, aka Bug ID CSCui33308.
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Analysis
by VulDB Data Team • 06/01/2021
The vulnerability identified as CVE-2013-5568 affects Cisco Adaptive Security Appliance (ASA) Software versions 9.0.3.6 and earlier, specifically targeting the auto-update mechanism that is designed to maintain device security and functionality. This flaw represents a critical weakness in the device's update handling process that can be exploited by remote attackers to disrupt service availability. The vulnerability is categorized under the Common Weakness Enumeration as CWE-129, which addresses improper validation of input boundaries, and falls within the ATT&CK framework under the technique T1499.3 for Network Denial of Service. The auto-update feature is intended to automatically download and install security patches and updates from Cisco's servers, but the implementation contains a critical flaw that allows malicious actors to manipulate the update process.
The technical implementation flaw resides in how the ASA software processes incoming update data during the auto-update sequence. When the device receives crafted update data, the parsing and validation mechanisms fail to properly handle malformed or specially constructed update packages. This failure leads to an unhandled exception or memory corruption within the update processing module, ultimately causing the device to crash and automatically reload its operating system. The vulnerability specifically exploits the update validation logic that does not adequately sanitize or verify the integrity of the update data before processing. Attackers can craft malicious update packages that trigger buffer overflows, invalid memory access patterns, or other memory corruption conditions that are not properly caught by the device's error handling mechanisms.
The operational impact of this vulnerability is severe and directly affects the availability of network security services provided by the affected ASA devices. A successful exploitation results in a complete device reload, which can take several minutes to complete and effectively removes the device from service during the recovery process. This disruption can have cascading effects on network security posture, as the device may be unavailable during critical security updates or when responding to security incidents. Organizations relying on these devices for firewall protection, intrusion prevention, and network access control may experience complete service outages that leave their networks vulnerable to external threats. The vulnerability affects both the primary and secondary active devices in high-availability configurations, potentially causing complete failover scenarios that impact network availability.
Mitigation strategies for this vulnerability should be implemented immediately and include several layers of protection. The primary recommendation is to upgrade to Cisco ASA Software version 9.0.3.7 or later, which contains the necessary patches to address the update processing flaw. Organizations should also implement network segmentation to limit access to the update mechanisms and restrict the ability of unauthorized users to interact with the device's update features. Additional protective measures include disabling the auto-update feature entirely if not required for operational necessity, implementing strict access controls on the management interfaces, and monitoring network traffic for suspicious update-related activities. The vulnerability's classification as a remote attack vector means that even unauthenticated attackers can exploit this issue, making it particularly dangerous in environments where network access is not strictly controlled. Security teams should also consider implementing network-based intrusion detection systems to monitor for patterns associated with this specific vulnerability and establish incident response procedures for rapid deployment of patches when vulnerabilities are discovered in operational environments.