CVE-2012-4658 in ios
Summary
by MITRE
The ios-authproxy implementation in Cisco IOS before 15.1(1)SY3 allows remote attackers to cause a denial of service (webauth and HTTP service outage) via vectors that trigger incorrectly terminated HTTP sessions, aka Bug ID CSCtz99447.
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Analysis
by VulDB Data Team • 05/11/2026
The vulnerability identified as CVE-2012-4658 affects Cisco IOS implementations that utilize the ios-authproxy feature, specifically impacting versions prior to 15.1(1)SY3. This flaw resides within the authentication proxy functionality that handles web authentication processes, creating a critical weakness that enables remote attackers to execute denial of service attacks against network infrastructure. The vulnerability manifests when the system encounters HTTP sessions that are improperly terminated, leading to cascading failures in web authentication services and potentially disrupting broader HTTP service operations.
The technical root cause of this vulnerability stems from inadequate session management within the ios-authproxy component, which fails to properly handle HTTP session termination sequences. When malformed or unexpected HTTP requests are processed, the authentication proxy enters an inconsistent state where it cannot properly clean up session resources or maintain proper connection handling. This improper session termination creates a condition where subsequent authentication requests either fail completely or cause the entire web authentication service to become unresponsive, effectively rendering the authentication proxy incapable of processing legitimate authentication requests from network users.
The operational impact of this vulnerability extends beyond simple service disruption, as it affects the fundamental authentication capabilities of Cisco network devices that rely on web-based authentication mechanisms. Network administrators may experience complete outages of web authentication services, forcing users to lose access to network resources that depend on web authentication for access control. The HTTP service disruption can compound the problem by affecting other services that depend on the same underlying HTTP infrastructure, potentially causing broader network operational issues. This vulnerability particularly impacts enterprise networks that utilize Cisco routers and switches configured with web authentication policies, where the authentication proxy serves as a critical component for user access control.
Mitigation strategies for CVE-2012-4658 should prioritize immediate software updates to Cisco IOS versions 15.1(1)SY3 or later, which contain the necessary patches to address the improper session termination handling. Network administrators should also implement monitoring solutions to detect unusual HTTP session patterns that may indicate exploitation attempts, while considering temporary network segmentation to limit the potential impact of successful attacks. The vulnerability aligns with CWE-400, which addresses improper handling of resource exhaustion conditions, and may be categorized under ATT&CK technique T1499.004 for network denial of service attacks. Organizations should also review their authentication proxy configurations to minimize the attack surface and implement proper access controls to limit remote exploitation opportunities while maintaining essential network functionality.