CVE-2021-1258 in AnyConnect Secure Mobility Client
Summary
by MITRE • 01/14/2021
A vulnerability in the upgrade component of Cisco AnyConnect Secure Mobility Client could allow an authenticated, local attacker with low privileges to read arbitrary files on the underlying operating system (OS) of an affected device. The vulnerability is due to insufficient file permission restrictions. An attacker could exploit this vulnerability by sending a crafted command from the local CLI to the application. A successful exploit could allow the attacker to read arbitrary files on the underlying OS of the affected device. The attacker would need to have valid user credentials to exploit this vulnerability.
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Analysis
by VulDB Data Team • 02/14/2021
The vulnerability identified as CVE-2021-1258 resides within the upgrade component of Cisco AnyConnect Secure Mobility Client, representing a critical security flaw that undermines the integrity of the affected system's file access controls. This vulnerability specifically targets the authorization mechanisms that govern file permissions within the application's upgrade functionality, creating an exploitable condition that allows authenticated local users to bypass normal security restrictions. The flaw manifests when the application fails to properly validate or restrict file access permissions during upgrade operations, enabling unauthorized file reading capabilities that extend beyond the intended scope of the application's operational boundaries.
The technical implementation of this vulnerability stems from inadequate input validation and permission enforcement within the upgrade module's command processing mechanism. When an authenticated user with valid credentials executes specific commands through the local command line interface, the application processes these inputs without sufficient verification of file access permissions. This weakness creates a path where malicious or privileged commands can be crafted to traverse the file system and access files that should normally be restricted to administrative users or system processes. The vulnerability operates at the intersection of privilege escalation and information disclosure, where the upgrade component's insufficient access controls allow for arbitrary file read operations that could expose sensitive system information, configuration files, or user data.
The operational impact of CVE-2021-1258 extends beyond simple information disclosure, as it provides attackers with the capability to gather intelligence about the underlying operating system and potentially access sensitive data stored within the system. Attackers could leverage this vulnerability to read system configuration files, user credentials, application data, or other sensitive information that could facilitate further exploitation attempts. The requirement for valid user credentials to exploit this vulnerability does not mitigate the risk significantly, as local access often implies that attackers have already established a foothold within the environment. This vulnerability aligns with CWE-276, which describes improper file permissions, and represents a classic example of how insufficient access control mechanisms can lead to unauthorized data access. The attack vector through the local CLI interface means that even if network-based protections are in place, local system compromise can still result in this vulnerability being exploited.
Organizations affected by this vulnerability should implement immediate mitigations to address the access control weakness within the AnyConnect upgrade component. The primary recommendation involves applying the latest security patches released by Cisco to remediate the permission enforcement flaws. Additionally, system administrators should review and tighten local file permissions for the AnyConnect application directories, implementing the principle of least privilege to limit file access capabilities. Network segmentation and monitoring solutions should be deployed to detect unusual command execution patterns from local interfaces that might indicate exploitation attempts. This vulnerability demonstrates the importance of proper access control implementation and highlights how seemingly minor permission issues in application components can lead to significant security risks. The ATT&CK framework categorizes this vulnerability under privilege escalation and credential access techniques, as it enables attackers to gain unauthorized access to system resources that would typically require elevated privileges. Organizations should also consider implementing privileged access management solutions to control and monitor access to critical system components, particularly those with upgrade or administrative capabilities that could be exploited through similar permission-based vulnerabilities.