CVE-2016-1459 in IOS
Summary
by MITRE
Cisco IOS 12.4 and 15.0 through 15.5 and IOS XE 3.13 through 3.17 allow remote authenticated users to cause a denial of service (device reload) via crafted attributes in a BGP message, aka Bug ID CSCuz21061.
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Analysis
by VulDB Data Team • 03/01/2019
Cisco IOS devices running versions 12.4 and 15.0 through 15.5, as well as IOS XE versions 3.13 through 3.17, contain a critical vulnerability that allows remote authenticated attackers to trigger a denial of service condition resulting in device reload. This vulnerability specifically affects Border Gateway Protocol implementations within these software versions and is catalogued under Bug ID CSCuz21061. The flaw manifests when the system processes malformed or crafted attributes within BGP messages, causing the device to crash and subsequently reload. This behavior represents a significant security concern as it can be exploited by attackers who have authenticated access to the network, potentially leading to service disruption and network instability.
The technical root cause of this vulnerability lies in insufficient input validation within the BGP message processing module of Cisco IOS. When the system receives a maliciously crafted BGP update message containing malformed attributes, the parsing routine fails to properly handle the unexpected data structures, leading to memory corruption or unexpected program flow that ultimately results in system instability. This type of vulnerability falls under CWE-129, Input Validation, and more specifically aligns with CWE-20, Improper Input Validation, as the system does not adequately validate the attributes within BGP messages before processing them. The vulnerability demonstrates characteristics of a buffer overflow or memory corruption issue that can be triggered through protocol message manipulation, making it particularly dangerous in network infrastructure devices.
The operational impact of this vulnerability extends beyond simple service disruption as it can affect the reliability and availability of critical network infrastructure. Network administrators may experience unexpected device reloads that can interrupt network connectivity, especially in environments where BGP is used for route distribution and network interconnection. The vulnerability is particularly concerning because it requires only authenticated access to exploit, meaning that attackers with legitimate network credentials can cause significant disruption. This attack vector aligns with ATT&CK technique T1499.004, Network Denial of Service, and can be classified as a persistent threat that undermines network stability and can potentially be used as a stepping stone for further attacks. The impact is compounded in large network environments where multiple devices may be affected simultaneously, leading to cascading failures.
Mitigation strategies for this vulnerability should include immediate patching of affected devices to the latest available IOS or IOS XE releases that contain the necessary fixes. Cisco has released security advisories and patches specifically addressing this issue, and network administrators should prioritize deployment of these updates across all affected systems. Additionally, implementing BGP message filtering and validation mechanisms at network boundaries can provide an additional layer of protection by preventing malformed messages from reaching vulnerable devices. Network segmentation and access control measures should also be reinforced to limit the potential attack surface, ensuring that only authorized personnel have the ability to establish BGP sessions. Monitoring systems should be configured to detect unusual device reload patterns that may indicate exploitation attempts, and network administrators should implement proper logging and alerting mechanisms to identify potential abuse of this vulnerability.