CVE-2017-12239 in IOS XE
Summary
by MITRE
A vulnerability in motherboard console ports of line cards for Cisco ASR 1000 Series Aggregation Services Routers and Cisco cBR-8 Converged Broadband Routers could allow an unauthenticated, physical attacker to access an affected device's operating system. The vulnerability exists because an engineering console port is available on the motherboard of the affected line cards. An attacker could exploit this vulnerability by physically connecting to the console port on the line card. A successful exploit could allow the attacker to gain full access to the affected device's operating system. This vulnerability affects only Cisco ASR 1000 Series Routers that have removable line cards and Cisco cBR-8 Converged Broadband Routers, if they are running certain Cisco IOS XE 3.16 through 16.5 releases. Cisco Bug IDs: CSCvc65866, CSCve77132.
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Analysis
by VulDB Data Team • 01/14/2021
This vulnerability represents a critical physical security flaw in Cisco's network infrastructure devices, specifically targeting the engineering console ports present on motherboard level components of line cards within the ASR 1000 Series Aggregation Services Routers and cBR-8 Converged Broadband Routers. The flaw exists due to the intentional inclusion of console ports during the engineering and manufacturing process, which were not properly secured or isolated from unauthorized physical access. According to the vulnerability analysis, these console ports remain accessible even in production environments, creating an attack surface that can be exploited by anyone with physical proximity to the affected hardware. The vulnerability is particularly concerning because it requires no authentication credentials, network access, or sophisticated attack vectors - simply physical connection to the console port on the line card.
The technical exploitation mechanism is straightforward yet devastating in its implications. Attackers can directly connect to the engineering console port through physical access to the line card, bypassing all network-based authentication mechanisms and security controls. This direct hardware-level access allows full system compromise and complete control over the router's operating system, enabling attackers to execute arbitrary code, modify configurations, extract sensitive data, or establish persistent backdoors. The vulnerability affects specific Cisco IOS XE software releases ranging from version 3.16 through 16.5, indicating that this was not a one-time design flaw but rather a persistent issue across multiple software versions of the affected product lines. This vulnerability aligns with CWE-254, which addresses "Security Features" and specifically targets weaknesses in physical security controls where engineering interfaces remain accessible in production environments.
The operational impact of this vulnerability extends far beyond simple unauthorized access, as it fundamentally undermines the security posture of network infrastructure devices that are critical to enterprise and service provider networks. Organizations utilizing these affected routers face significant risks including potential network disruption, data exfiltration, and complete system compromise without any indication of unauthorized access attempts. The attack vector being physical access means that traditional network-based monitoring and intrusion detection systems provide no protection against this specific threat. This vulnerability directly relates to ATT&CK technique T1018, which covers "Remote System Discovery," as attackers could potentially use this access to map network topology and identify additional targets within the network infrastructure. The impact is particularly severe for service providers and enterprises that deploy these routers in locations where physical security controls may be inadequate or where unauthorized personnel might gain access to network equipment.
Mitigation strategies for this vulnerability require a combination of physical security measures and software updates. Organizations should implement strict physical access controls to network equipment, including locked server rooms, access logs, and restricted personnel access to areas containing affected routers. The most effective solution involves applying the relevant Cisco IOS XE software updates that address this specific console port vulnerability, though this requires careful planning to avoid service disruption during the update process. Network administrators should also conduct comprehensive inventory audits to identify all affected devices within their infrastructure and implement monitoring procedures to detect any unauthorized physical access attempts. Additionally, organizations should consider implementing network segmentation and access control measures that can limit the impact of any successful compromise, while also developing incident response procedures specifically designed to address physical security breaches of network infrastructure equipment. The vulnerability demonstrates the critical importance of securing all hardware interfaces, including those intended for engineering and diagnostic purposes, as these can provide attackers with direct pathways to system compromise that bypass traditional cybersecurity controls.