CVE-2018-0180 in IOS
Summary
by MITRE
Multiple vulnerabilities in the Login Enhancements (Login Block) feature of Cisco IOS Software could allow an unauthenticated, remote attacker to trigger a reload of an affected system, resulting in a denial of service (DoS) condition. These vulnerabilities affect Cisco devices that are running Cisco IOS Software Release 15.4(2)T, 15.4(3)M, or 15.4(2)CG and later. Cisco Bug IDs: CSCuy32360, CSCuz60599.
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Analysis
by VulDB Data Team • 09/09/2024
The vulnerability described in CVE-2018-0180 resides within the Login Enhancements feature of Cisco IOS Software, specifically targeting the Login Block functionality that governs authentication mechanisms on network devices. This critical weakness affects multiple Cisco IOS releases including 15.4(2)T, 15.4(3)M, and 15.4(2)CG and subsequent versions, creating a significant exposure across numerous network infrastructure components. The vulnerability represents a remote code execution risk that can be exploited by unauthenticated attackers without requiring any prior access credentials, making it particularly dangerous in enterprise environments where network devices are often accessible from external networks.
The technical flaw manifests through improper input validation and handling within the login block processing module of Cisco IOS Software. When an attacker sends specially crafted malformed input to the affected system, the device fails to properly validate the input parameters and subsequently enters an unstable state that leads to automatic system reload. This behavior stems from inadequate error handling mechanisms within the authentication framework, where malformed login requests can trigger buffer overflows or memory corruption conditions that cause the operating system to restart. The vulnerability operates at the application layer and leverages the inherent trust placed in authentication services, making it difficult to detect through traditional network monitoring approaches.
The operational impact of this vulnerability extends beyond simple service disruption, as the denial of service condition can result in complete network outages for affected devices. Network administrators may experience extended downtime while systems restart and recover, potentially disrupting critical business operations and communication services. The vulnerability's remote exploitability means that attackers can target devices from outside the network perimeter, eliminating the need for physical access or internal network presence. This characteristic aligns with ATT&CK technique T1190 for exploit via network service and follows CWE-121 for buffer overflow conditions in the context of authentication services.
Organizations affected by this vulnerability face significant security implications as the DoS condition can be triggered repeatedly, potentially leading to sustained service disruption. The attack vector requires no authentication credentials, making it accessible to any attacker with network connectivity to the affected device, which increases the attack surface considerably. Network security teams must consider the potential for this vulnerability to be used as part of broader attack campaigns where initial access is achieved through other means, with this DoS vulnerability serving as a method to maintain persistence or disrupt network operations. The vulnerability also demonstrates the importance of proper input validation and error handling in authentication systems, as outlined in security best practices for secure coding and network device hardening.
Mitigation strategies should include immediate software updates to the latest Cisco IOS releases that contain patches for these vulnerabilities, as well as implementing network segmentation to limit exposure of critical devices to external threats. Network administrators should consider disabling unnecessary authentication services when possible and implement monitoring solutions that can detect unusual reload patterns or authentication failures that may indicate exploitation attempts. Additionally, organizations should conduct comprehensive vulnerability assessments to identify all affected devices and establish incident response procedures to quickly address any exploitation attempts, ensuring that the network infrastructure maintains operational integrity during and after remediation efforts.