CVE-2016-1348 in IOS
Summary
by MITRE
Cisco IOS 15.0 through 15.5 and IOS XE 3.3 through 3.16 allow remote attackers to cause a denial of service (device reload) via a crafted DHCPv6 Relay message, aka Bug ID CSCus55821.
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Analysis
by VulDB Data Team • 10/15/2024
The vulnerability identified as CVE-2016-1348 represents a critical denial of service flaw affecting Cisco IOS and IOS XE operating systems across multiple versions. This weakness specifically targets the DHCPv6 relay functionality, which is essential for network infrastructure devices that handle dynamic host configuration protocol version 6 communications. The flaw allows remote attackers to exploit a buffer handling issue within the DHCPv6 relay message processing mechanism, leading to unexpected device behavior and potential system instability.
The technical root cause of this vulnerability stems from insufficient input validation and memory management within the DHCPv6 relay implementation. When a maliciously crafted DHCPv6 relay message is received by an affected Cisco device, the system fails to properly handle the malformed packet structure, resulting in a buffer overflow condition. This condition triggers an abrupt system restart or device reload, effectively rendering the network infrastructure unavailable to legitimate users. The vulnerability operates at the network protocol level, specifically within the IPv6 addressing and configuration framework where DHCPv6 serves as the primary means of automatic address assignment and configuration parameter distribution.
From an operational impact perspective, this vulnerability poses significant risks to network availability and business continuity. Network administrators responsible for maintaining Cisco devices across enterprise and service provider environments face potential disruption when attackers exploit this flaw. The remote nature of the attack means that adversaries can trigger device reloads from outside the network perimeter without requiring physical access or authentication credentials. This makes the vulnerability particularly dangerous as it can be exploited by anyone who can reach the affected device's network interface, potentially leading to widespread service degradation or complete network outages depending on the criticality of the compromised device.
The vulnerability maps to CWE-121, which describes stack-based buffer overflow conditions, and aligns with several ATT&CK tactics including TA0040 (Impact) under T1499 (Endpoint Denial of Service) and T1566 (Phishing with Malicious Attachment) when considering how attackers might deliver malicious DHCPv6 relay messages. Network security professionals should consider implementing network segmentation and access control measures to limit exposure, particularly on devices that process DHCPv6 relay messages. The affected versions span a broad range of Cisco IOS and IOS XE releases, indicating that organizations maintaining legacy network infrastructure may be particularly vulnerable.
Mitigation strategies should include immediate deployment of Cisco's official security patches and updates addressing the specific buffer handling issues in DHCPv6 relay processing. Network administrators should also implement ingress filtering and access control lists to restrict DHCPv6 relay message traffic to trusted sources only. Monitoring network traffic for unusual DHCPv6 relay message patterns can help detect potential exploitation attempts. Additionally, organizations should consider implementing network intrusion detection systems with signature-based detection capabilities specifically designed to identify malicious DHCPv6 relay traffic patterns that could indicate exploitation attempts. The vulnerability demonstrates the importance of maintaining up-to-date network infrastructure and implementing robust input validation mechanisms across all network protocol implementations.