CVE-2013-5508 in ASA
Summary
by MITRE
The SQL*Net inspection engine in Cisco Adaptive Security Appliance (ASA) Software 7.x before 7.2(5.12), 8.x before 8.2(5.44), 8.3.x before 8.3(2.39), 8.4.x before 8.4(6), 8.5.x before 8.5(1.18), 8.6.x before 8.6(1.12), 8.7.x before 8.7(1.6), 9.0.x before 9.0(2.10), and 9.1.x before 9.1(2) and Firewall Services Module (FWSM) 3.1.x and 3.2.x before 3.2(27) and 4.x before 4.1(14) allows remote attackers to cause a denial of service (device reload) via crafted segmented Transparent Network Substrate (TNS) packets, aka Bug ID CSCub98434.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 05/26/2021
The vulnerability described in CVE-2013-5508 represents a critical flaw in Cisco's Adaptive Security Appliance software and Firewall Services Module implementations that specifically affects the SQL*Net inspection engine. This vulnerability resides within the network traffic inspection capabilities of Cisco's security appliances, which are designed to monitor and filter network traffic based on application layer protocols. The affected systems process Transparent Network Substrate (TNS) packets that are part of Oracle's database communication protocol stack, making this issue particularly dangerous in environments where database connectivity is prevalent.
The technical flaw manifests when the SQL*Net inspection engine encounters crafted segmented TNS packets that exploit a buffer handling or parsing error within the ASA software's protocol inspection mechanisms. These malicious packets are specifically designed to trigger an improper response from the inspection engine, causing the device to enter an unstable state that ultimately results in a complete device reload or crash. The vulnerability is particularly insidious because it operates at the application layer inspection level, meaning that even if the packets are properly filtered at lower network layers, they can still exploit this weakness when processed by the ASA's protocol inspection engine. This behavior aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a classic case of improper input validation in protocol handling components.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the entire network security infrastructure. When exploited successfully, the denial of service condition causes the affected Cisco ASA or FWSM device to reload, which can result in temporary loss of network security services, including firewall rules enforcement, intrusion prevention capabilities, and application layer filtering. This disruption can be particularly devastating in enterprise environments where these devices serve as critical security gateways, potentially leaving networks exposed to attacks during the reload period. The vulnerability affects multiple software versions across different Cisco ASA release lines, indicating a widespread issue that required coordinated patching efforts across the product portfolio. The attack vector requires only remote network access to deliver the malicious TNS packets, making it accessible to attackers with minimal network proximity requirements.
Organizations affected by this vulnerability should immediately implement mitigation strategies that include applying the appropriate software patches released by Cisco, which address the specific buffer handling issues in the SQL*Net inspection engine. Network administrators should also consider implementing additional monitoring and alerting mechanisms to detect unusual patterns of TNS traffic that might indicate attempted exploitation. The implementation of access control lists or firewall rules that restrict TNS traffic to necessary network segments can provide additional protection layers. From an ATT&CK framework perspective, this vulnerability maps to the T1499.004 technique related to Network Denial of Service, and the T1071.004 sub-technique for Application Layer Protocol. Organizations should also consider implementing network segmentation strategies to limit the blast radius of potential exploitation, as well as maintaining robust incident response procedures that account for the possibility of device reloads due to this specific vulnerability. The remediation process requires careful planning to avoid service interruptions, as the patching process itself may require device reloads.