CVE-2017-12281 in Aironet
Summary
by MITRE
A vulnerability in the implementation of Protected Extensible Authentication Protocol (PEAP) functionality for standalone configurations of Cisco Aironet 1800, 2800, and 3800 Series Access Points could allow an unauthenticated, adjacent attacker to bypass authentication and connect to an affected device. The vulnerability exists because the affected device uses an incorrect default configuration setting of fail open when running in standalone mode. An attacker could exploit this vulnerability by attempting to connect to an affected device. A successful exploit could allow the attacker to bypass authentication and connect to the affected device. This vulnerability affects Cisco Aironet 1800, 2800, and 3800 Series Access Points that are running a vulnerable software release and use WLAN configuration settings that include FlexConnect local switching and central authentication with MAC filtering. Cisco Bug IDs: CSCvd46314.
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Analysis
by VulDB Data Team • 01/21/2021
The vulnerability described in CVE-2017-12281 represents a critical flaw in the Protected Extensible Authentication Protocol (PEAP) implementation within Cisco Aironet access points, specifically affecting models 1800, 2800, and 3800 series operating in standalone configurations. This security weakness stems from an improper default configuration that establishes a fail-open policy when the access point operates independently without a wireless controller. The vulnerability creates a significant authentication bypass opportunity for adjacent attackers who can exploit the misconfigured security settings to gain unauthorized network access. The flaw is particularly concerning because it allows unauthenticated attackers to establish connections to the affected devices without proper authentication mechanisms being enforced, undermining the fundamental security posture of the wireless network infrastructure.
The technical implementation of this vulnerability manifests through the incorrect default configuration that enables fail-open behavior in standalone mode operations. When these access points are configured for standalone operation with FlexConnect local switching and central authentication combined with MAC filtering, the system fails to properly enforce authentication requirements. This misconfiguration creates a logical flaw in the authentication flow where the device accepts connections regardless of proper authentication status, effectively opening a backdoor for unauthorized access. The vulnerability specifically impacts devices that are running vulnerable software versions and are configured with the particular WLAN settings mentioned in the Cisco bug ID CSCvd46314. The flaw operates at the network authentication layer, where the PEAP implementation fails to properly validate client credentials before granting network access, creating a persistent security gap that can be exploited by attackers within the physical proximity of the affected devices.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it fundamentally compromises the security architecture of wireless networks utilizing affected Cisco access points. An attacker exploiting this vulnerability could gain full network access to the wireless infrastructure, potentially leading to data breaches, man-in-the-middle attacks, or further network compromise through lateral movement. The vulnerability affects organizations that rely on standalone access points for their wireless deployments, particularly those using FlexConnect configurations where local switching is enabled while central authentication is maintained. This creates a dangerous scenario where network administrators believe their authentication mechanisms are properly enforced, while attackers can bypass these controls entirely through simple network connection attempts. The impact is particularly severe for organizations with limited network segmentation, as successful exploitation could provide attackers with access to critical internal systems and data resources.
Mitigation strategies for this vulnerability require immediate configuration changes to address the default fail-open behavior in standalone mode operations. Network administrators should disable the vulnerable default settings and implement proper authentication enforcement mechanisms that prevent unauthorized connections to affected access points. The recommended approach includes updating firmware to versions that address the specific bug referenced in Cisco CSCvd46314, reconfiguring WLAN settings to eliminate the combination of FlexConnect local switching with central authentication that triggers the vulnerability, and implementing additional network segmentation measures to limit the impact of successful exploitation attempts. Security teams should also consider implementing network access control policies that restrict physical access to wireless infrastructure and monitor for unusual connection patterns that might indicate exploitation attempts. Organizations should perform comprehensive vulnerability assessments to identify all affected devices and ensure that proper authentication mechanisms are enforced across their entire wireless infrastructure. This vulnerability aligns with CWE-305 authentication bypass weaknesses and represents a significant concern under ATT&CK framework domain of Initial Access through Network Logon, where attackers exploit authentication flaws to establish footholds within network environments.