CVE-2015-7600 in VPN Client
Summary
by MITRE
Cisco VPN Client 5.x through 5.0.07.0440 uses weak permissions for vpnclient.ini, which allows local users to gain privileges by entering an arbitrary program name in the Command field of the ApplicationLauncher section.
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Analysis
by VulDB Data Team • 11/17/2024
The vulnerability identified as CVE-2015-7600 affects Cisco VPN Client versions 5.x through 5.0.07.0440 and represents a privilege escalation flaw stemming from weak file permissions. This issue resides in the vpnclient.ini configuration file which is improperly protected, allowing local attackers to manipulate the application's execution behavior. The vulnerability specifically targets the ApplicationLauncher section within the configuration file where the Command field can be modified to execute arbitrary programs with elevated privileges. This weakness directly violates security principles of least privilege and proper access control enforcement. The configuration file's weak permissions create an attack surface where unauthorized local users can modify critical application parameters that govern program execution. The vulnerability is categorized under CWE-276, which addresses improper permissions for system resources, and aligns with ATT&CK technique T1068, which covers local privilege escalation through system modification.
The technical exploitation of this vulnerability occurs when a local user modifies the Command field within the ApplicationLauncher section of vpnclient.ini to point to a malicious executable. When the VPN client subsequently executes the modified command, it runs with the elevated privileges of the VPN client process, typically running as a privileged user or system account. This creates a direct path for privilege escalation where the attacker can execute arbitrary code with higher privileges than their original access level. The vulnerability demonstrates poor privilege separation and inadequate input validation within the client configuration parsing mechanism. The weak file permissions allow modification of the configuration file without proper authorization, bypassing normal access controls that should prevent such modifications. This flaw is particularly dangerous in multi-user environments where local access might be granted to untrusted users who could leverage this vulnerability to elevate their privileges.
The operational impact of CVE-2015-7600 extends beyond simple privilege escalation to potentially enable full system compromise. Once an attacker gains elevated privileges through this vulnerability, they can access sensitive system resources, modify critical files, install malware, or establish persistent access. The vulnerability affects organizations using Cisco VPN Client versions that have not been updated with proper security patches, creating widespread exposure across various network environments. The attack vector is relatively simple to execute, requiring only local access to modify a configuration file, making it particularly dangerous in environments where local user access is not properly restricted. The vulnerability also impacts the integrity of the VPN client application, as it allows unauthorized modification of the application's intended behavior. This can lead to denial of service conditions or more serious security breaches where the modified execution path is used to bypass security controls. Organizations relying on these older VPN client versions face significant risk, especially in environments where privileged accounts are compromised.
Mitigation strategies for CVE-2015-7600 should focus on immediate patching of affected Cisco VPN Client versions to address the weak file permissions and improve access control mechanisms. System administrators should implement proper file permission controls on vpnclient.ini and related configuration files to prevent unauthorized modifications. The recommended approach includes setting restrictive permissions that allow only authorized users or processes to modify these critical files. Organizations should also conduct comprehensive vulnerability assessments to identify all systems running affected Cisco VPN Client versions and ensure they are updated to patched releases. Additional mitigations include implementing application whitelisting policies to restrict execution of unauthorized programs, monitoring for suspicious modifications to VPN client configuration files, and applying principle of least privilege access controls to all system resources. Security teams should also consider network segmentation and monitoring to detect potential exploitation attempts and maintain audit logs of configuration file modifications. The vulnerability highlights the importance of proper file access controls and the need for regular security updates to address known weaknesses in network client applications.