CVE-2018-0441 in IOS Access Point
Summary
by MITRE
A vulnerability in the 802.11r Fast Transition feature set of Cisco IOS Access Points (APs) Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to a corruption of certain timer mechanisms triggered by specific roaming events. This corruption will eventually cause a timer crash. An attacker could exploit this vulnerability by sending malicious reassociation events multiple times to the same AP in a short period of time, causing a DoS condition on the affected AP.
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Analysis
by VulDB Data Team • 05/30/2023
The vulnerability identified as CVE-2018-0441 resides within the 802.11r Fast Transition feature implementation of Cisco IOS Access Points, representing a critical security flaw that compromises network availability. This issue specifically affects wireless infrastructure devices that implement the IEEE 802.11r standard for rapid roaming between access points, which is essential for maintaining seamless connectivity in enterprise and enterprise-grade wireless networks. The vulnerability demonstrates the inherent complexity of wireless protocol implementations and their susceptibility to exploitation through carefully crafted network events that manipulate internal device state mechanisms.
The technical root cause of this vulnerability stems from improper handling of timer mechanisms within the Cisco IOS software stack when processing specific roaming events. When an access point receives malicious reassociation requests in rapid succession, the internal timer management system becomes corrupted, leading to a cascading failure that ultimately results in a complete system crash or reboot. This timer corruption occurs because the software fails to properly validate or sanitize the timing parameters associated with 802.11r Fast Transition operations, creating a condition where repeated malicious inputs can overwhelm the device's state management capabilities. The flaw operates at the protocol level within the wireless access point's operating system, making it particularly dangerous as it can be triggered without requiring authentication or advanced network privileges.
From an operational perspective, this vulnerability creates significant risk for organizations relying on Cisco wireless infrastructure, as an adjacent attacker with minimal network access can induce a denial of service condition that disrupts wireless connectivity for all users connected to the affected access point. The attack vector requires only local network proximity and the ability to send crafted wireless frames, making it particularly concerning for environments where physical security controls may be insufficient. The DoS condition can persist until manual intervention occurs, potentially causing widespread disruption to business operations, especially in mission-critical environments where wireless connectivity is essential for operations. Network administrators face the challenge of detecting such attacks, as they may appear as legitimate network events while actually causing system instability.
The exploitation of this vulnerability aligns with ATT&CK technique T1499.002 for network denial of service and demonstrates how wireless protocols can be targeted through protocol-level attacks rather than traditional network security breaches. Organizations should implement network segmentation and wireless access point monitoring to detect unusual roaming patterns that might indicate exploitation attempts. Cisco has released software updates addressing this vulnerability through patches that improve timer validation and error handling within the 802.11r implementation. The CWE classification for this vulnerability falls under CWE-129, which addresses improper validation of input ranges, as the system fails to properly validate the timing parameters associated with roaming events. Security teams should prioritize patch management for affected devices and consider implementing wireless intrusion detection systems to monitor for suspicious roaming activity patterns that could indicate exploitation attempts.