CVE-2012-3052 in VPN Client
Summary
by MITRE
Untrusted search path vulnerability in Cisco VPN Client 5.0 allows local users to gain privileges via a Trojan horse DLL in the current working directory, aka Bug ID CSCua28747.
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Analysis
by VulDB Data Team • 12/13/2021
The vulnerability identified as CVE-2012-3052 represents a critical untrusted search path weakness in Cisco VPN Client version 5.0 that enables local attackers to escalate privileges through strategic placement of malicious DLL files. This flaw resides in the client application's dynamic link library loading mechanism, where the software fails to properly validate the source and integrity of dynamically loaded components. The vulnerability specifically manifests when the application searches for required DLL modules in the current working directory before examining system directories, creating an opportunity for privilege escalation attacks. The bug ID CSCua28747 documents this weakness within Cisco's internal tracking systems, highlighting the dangerous implications of improper library resolution practices in enterprise security software. This issue falls under the broader category of DLL hijacking vulnerabilities that have plagued Windows-based systems for years.
The technical implementation of this vulnerability exploits the Windows DLL search order mechanism, where applications first search the current working directory for required libraries before examining system paths. When a user executes the Cisco VPN Client from a directory containing a malicious DLL with the same name as a legitimate system library, the Trojan horse module gets loaded instead of the genuine component. This behavior directly violates security principles of least privilege and proper library loading practices. The vulnerability is particularly dangerous because it requires no elevated permissions to exploit, as local users can simply place the malicious DLL in the working directory of the vulnerable application. Attackers can leverage this weakness to execute arbitrary code with the privileges of the targeted user, potentially leading to complete system compromise if the user has administrative rights.
The operational impact of CVE-2012-3052 extends beyond simple privilege escalation, as it creates a persistent backdoor mechanism within enterprise networks where the Cisco VPN Client is deployed. Organizations running affected versions of the Cisco VPN Client face significant risk of insider threats and lateral movement attacks, as attackers can maintain access even after initial compromise. The vulnerability affects the integrity of the VPN client's security model, undermining trust in the application's ability to provide secure network access. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and persistence mechanisms, specifically targeting T1059 Command and Scripting Interpreter and T1068 Exploitation for Privilege Escalation. The vulnerability also relates to CWE-427 Uncontrolled Search Path, which describes the condition where an application searches for libraries or other resources in an untrusted location, creating opportunities for malicious code injection.
Organizations should implement immediate mitigations including updating to patched versions of the Cisco VPN Client, implementing strict directory permissions on system directories where the application executes, and conducting thorough security audits of all user workstations. System administrators should enforce application whitelisting policies that restrict the execution of unsigned or untrusted DLLs, while also monitoring for suspicious file placement activities in directories where the VPN client operates. The remediation process requires careful coordination with network security teams to ensure that all instances of the vulnerable software are identified and updated across the enterprise. Additionally, security awareness training should emphasize the dangers of executing applications from untrusted directories and the importance of maintaining proper file system permissions. Organizations should also consider implementing endpoint protection solutions that can detect and prevent DLL injection attacks, as these mechanisms provide additional defense layers against exploitation attempts. The vulnerability underscores the critical importance of secure coding practices and proper library loading procedures in enterprise security applications, particularly those handling sensitive network access credentials and privileged operations.