CVE-2016-1425 in IOS
Summary
by MITRE
Cisco IOS 15.0(2)SG5, 15.1(2)SG3, 15.2(1)E, 15.3(3)S, and 15.4(1.13)S allows remote attackers to cause a denial of service (device crash) via a crafted LLDP packet, aka Bug ID CSCun66735.
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Analysis
by VulDB Data Team • 10/14/2024
Cisco IOS devices running specific software versions are vulnerable to a remote denial of service attack through manipulation of Link Layer Discovery Protocol packets. This vulnerability affects multiple release branches including 15.0(2)SG5, 15.1(2)SG3, 15.2(1)E, 15.3(3)S, and 15.4(1.13)S, indicating a widespread issue across the IOS codebase. The flaw specifically manifests when the device receives a crafted LLDP packet that triggers an improper handling of the packet structure, leading to a complete device crash and subsequent denial of service condition. The vulnerability operates at the network protocol level where LLDP packets are processed without adequate validation of packet fields, creating a condition where malformed data can cause the operating system to enter an unrecoverable state.
The technical implementation of this vulnerability involves the IOS operating system's failure to properly validate LLDP packet contents during processing. When a specially crafted LLDP packet is received, the system attempts to parse and handle the packet structure in a manner that causes memory corruption or stack overflow conditions. This processing error results in an immediate system crash that requires manual intervention to restore normal operation. The vulnerability is classified as a remote attack vector because no authentication or local access is required to exploit it, making it particularly dangerous in network environments where devices are exposed to untrusted traffic. The flaw represents a classic buffer overflow condition within the LLDP processing module, where the device does not enforce proper bounds checking on incoming packet data.
The operational impact of this vulnerability extends beyond simple device unavailability, as it can affect network reliability and availability across entire infrastructure segments. Network administrators may experience unexpected outages when devices crash, particularly in environments where LLDP is enabled for network discovery and device management purposes. The vulnerability is particularly concerning in critical infrastructure environments where continuous network availability is essential, as the attack can be executed remotely without any prior access credentials. Organizations may face significant downtime and operational disruption when multiple devices in the network are affected, potentially requiring coordinated maintenance windows to restore service. The vulnerability also impacts network monitoring and management systems that rely on LLDP data for topology discovery and device inventory management.
Mitigation strategies for this vulnerability should include immediate software updates to the latest IOS releases that contain patches addressing the LLDP packet processing flaw. Cisco has released specific software releases that correct the vulnerability, and organizations should prioritize upgrading affected devices to these patched versions. Network segmentation and access control measures can provide temporary protection by limiting the exposure of vulnerable devices to untrusted networks, though this approach does not eliminate the underlying vulnerability. Network administrators should implement monitoring solutions to detect unusual LLDP traffic patterns that may indicate exploitation attempts, as the attack can be automated and executed at scale. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a typical example of how improper input validation can lead to system instability and denial of service conditions. From an ATT&CK framework perspective, this vulnerability maps to the T1499.004 technique for network denial of service, demonstrating how protocol-level flaws can be exploited to compromise network availability.