CVE-2018-0179 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-2018-0179 resides within the Login Enhancements feature of Cisco IOS Software, specifically targeting the Login Block functionality that governs authentication processes on network devices. This critical flaw affects Cisco routers and switches operating on IOS releases 15.4(2)T, 15.4(3)M, and 15.4(2)CG and subsequent versions, making it a widespread concern across numerous network infrastructure deployments. The vulnerability operates through a carefully crafted sequence of authentication attempts that exploit weaknesses in how the system handles login blocking mechanisms, potentially allowing unauthorized actors to disrupt normal network operations.
Technical exploitation of this vulnerability occurs when an unauthenticated remote attacker crafts specific network packets that trigger a malformed state within the IOS login processing subsystem. The flaw manifests as a buffer overflow or improper state management issue within the Login Block feature, causing the system to enter an unrecoverable condition that ultimately results in an automatic system reload. This behavior is categorized under CWE-121 as heap-based buffer overflow, though the exact technical implementation involves complex interactions between authentication state machines and system resource management within the IOS kernel. The attack vector requires no prior authentication credentials, making it particularly dangerous as it can be exploited from any network location with access to the affected device's management interfaces.
The operational impact of CVE-2018-0179 represents a severe denial of service condition that can compromise network availability and business continuity. When successfully exploited, the vulnerability forces affected Cisco devices to undergo automatic system reloads, effectively removing them from network operations until manual intervention occurs. This disruption can cascade through network infrastructure, particularly in environments where these devices serve as critical routing points, core switches, or border gateways. The vulnerability's remote nature means that attackers can initiate the attack from outside the network perimeter, making it difficult to defend against through traditional network segmentation measures. Organizations may experience extended downtime as system administrators must manually restart affected devices and verify system integrity, with potential for repeated attacks if the vulnerability remains unpatched.
Mitigation strategies for this vulnerability should prioritize immediate patch deployment as provided by Cisco through their security advisory releases. Organizations must update their affected devices to IOS versions that contain the necessary security fixes, typically found in later releases that address the specific buffer management issues within the Login Block feature. Network segmentation and access control measures can provide temporary protection by limiting exposure of vulnerable devices to untrusted networks, though this approach does not eliminate the underlying vulnerability. Monitoring systems should be enhanced to detect anomalous authentication patterns that might indicate exploitation attempts, with network administrators implementing logging configurations that track login failures and system reload events. The ATT&CK framework categorizes this vulnerability under T1499.004 for Network Denial of Service and T1566.001 for Phishing, as exploitation often involves crafting malicious network traffic to trigger the vulnerable system behavior. Security teams should also implement continuous vulnerability assessment procedures to identify and remediate similar issues across their entire network infrastructure, particularly focusing on authentication mechanisms and system resource handling within network operating systems.