CVE-2021-1449 in Aironet
Summary
by MITRE • 03/25/2021
A vulnerability in the boot logic of Cisco Access Points Software could allow an authenticated, local attacker to execute unsigned code at boot time. The vulnerability is due to an improper check that is performed by the area of code that manages system startup processes. An attacker could exploit this vulnerability by modifying a specific file that is stored on the system, which would allow the attacker to bypass existing protections. A successful exploit could allow the attacker to execute unsigned code at boot time and bypass the software image verification check part of the secure boot process of an affected device. Note: To exploit this vulnerability, the attacker would need to have access to the development shell (devshell) on the device.
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Analysis
by VulDB Data Team • 04/05/2021
Cisco Access Points are critical network infrastructure devices that serve as wireless access points for enterprise and consumer networks, implementing secure boot mechanisms to protect against unauthorized code execution. The vulnerability in CVE-2021-1449 resides within the boot logic of these devices, specifically in the system startup process management code that handles software image verification during device initialization. This flaw represents a fundamental security weakness in the secure boot implementation that is designed to prevent unauthorized code execution during system boot cycles. The vulnerability stems from an improper validation check within the boot process that fails to adequately verify the integrity of system files before execution, creating a window of opportunity for attackers to bypass established security controls.
The technical exploitation of this vulnerability requires an attacker to possess access to the development shell or devshell on the affected device, which represents a significant prerequisite for successful exploitation. Once authenticated, the attacker can modify a specific file stored on the system that is critical to the boot process, effectively manipulating the secure boot verification mechanism. This modification allows the attacker to execute unsigned code at boot time, circumventing the software image verification checks that are integral to the secure boot process. The vulnerability directly impacts the integrity verification components of the boot sequence, where the system should validate the authenticity and integrity of all boot components before execution. This flaw enables attackers to inject malicious code that executes with system privileges during the boot process, potentially establishing persistent backdoors or executing malicious payloads that can compromise the entire network infrastructure.
The operational impact of this vulnerability extends beyond individual device compromise to threaten entire network infrastructures that rely on Cisco Access Points for wireless connectivity. Attackers who successfully exploit this vulnerability can establish persistent access points within the network, potentially enabling them to monitor traffic, redirect connections, or execute further attacks against other network segments. The secure boot bypass capability means that even if the device is later patched or updated, the attacker's malicious code could remain active during the boot process, creating a persistent threat that survives system reboots. This vulnerability undermines the fundamental security model of network access points, where the boot process is designed to be the first line of defense against unauthorized code execution. The implications are particularly severe in enterprise environments where access points serve as critical network entry points and where wireless network security is paramount to overall network defense.
Organizations should implement immediate mitigations including restricting physical and logical access to development shells on affected devices, conducting comprehensive vulnerability assessments to identify potentially compromised systems, and establishing network monitoring to detect anomalous boot behavior or unauthorized file modifications. The vulnerability aligns with CWE-284 Access Control Issues, specifically related to improper access control during system initialization phases. From an ATT&CK perspective, this vulnerability maps to T1068 Local Privilege Escalation and T1542.001 Boot or Logon Autostart Execution, as it enables execution of malicious code during system boot with elevated privileges. Network segmentation should be implemented to limit access to affected devices, and regular security audits should be conducted to verify the integrity of boot processes. Device firmware should be updated to versions that address the specific boot logic validation flaw, and organizations should consider implementing additional monitoring for unauthorized file modifications in critical system directories. The vulnerability demonstrates the critical importance of maintaining secure boot processes and proper access controls during system initialization, as these phases represent the most vulnerable moments in a device's operational lifecycle.