CVE-2014-3388 in ASA
Summary
by MITRE
The DNS inspection engine in Cisco ASA Software 9.0 before 9.0(4.13), 9.1 before 9.1(5.7), and 9.2 before 9.2(2) allows remote attackers to cause a denial of service (device reload) via crafted DNS packets, aka Bug ID CSCuo68327.
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Analysis
by VulDB Data Team • 02/21/2022
The vulnerability identified as CVE-2014-3388 represents a critical denial of service flaw within Cisco Adaptive Security Appliance (ASA) software systems. This weakness specifically affects the DNS inspection engine component that processes and analyzes Domain Name System traffic passing through the security appliance. The vulnerability exists in multiple versions of Cisco ASA software including 9.0 before 9.0(4.13), 9.1 before 9.1(5.7), and 9.2 before 9.2(2), making it a widespread concern across several major software releases. The flaw enables remote attackers to exploit the device's DNS processing capabilities without requiring authentication or physical access to the network infrastructure.
The technical implementation of this vulnerability stems from inadequate input validation within the DNS inspection engine's packet processing logic. When the appliance encounters specially crafted DNS packets containing malformed or unexpected data structures, the inspection engine fails to properly handle these malformed inputs. This improper handling causes the system to enter an unstable state where critical processing threads either crash or become unresponsive, ultimately leading to a complete device reload or system reboot. The vulnerability operates at the network protocol level where DNS traffic is inspected for potential threats, making it particularly dangerous as it can be triggered by legitimate network traffic that appears to be normal DNS queries.
From an operational impact perspective, this vulnerability presents a significant risk to network availability and business continuity. Organizations relying on Cisco ASA appliances for network security face the potential for unexpected service interruptions that could last from several minutes to hours depending on the device's recovery process. The remote exploitation capability means that attackers can trigger the denial of service from anywhere on the internet without requiring local network access or credentials, making it particularly attractive to threat actors seeking to disrupt services. The automatic device reload process can result in temporary loss of network security protections, potentially exposing the network to other attacks during the recovery period.
The vulnerability aligns with CWE-121, which describes buffer overflow conditions where insufficient bounds checking allows attackers to overwrite memory locations, and can be mapped to ATT&CK technique T1499.004, which covers network disruption through resource exhaustion or system instability. Organizations should implement immediate mitigations including applying the relevant Cisco security patches and updates that address the specific DNS inspection engine flaw. Network administrators should also consider implementing additional monitoring to detect unusual patterns of DNS traffic that might indicate exploitation attempts, and establish incident response procedures to quickly address any potential exploitation events. The remediation process requires careful planning to minimize network disruption during patch deployment, as the device reload functionality that triggers the vulnerability is also part of the patch installation process itself, creating a potential chicken-and-egg scenario that requires specific deployment procedures to avoid service interruption.