CVE-2005-2579 in Contivity VPN Client
Summary
by MITRE
Nortel Contivity VPN Client V05_01.030, when configuring a certificate to be used as authentication, does not properly drop system privileges, which allows local users to gain privileges by opening a program with the File Open dialog box.
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Analysis
by VulDB Data Team • 07/04/2019
The vulnerability identified as CVE-2005-2579 affects the Nortel Contivity VPN Client version 05_01.030 and represents a critical privilege escalation flaw within the certificate authentication configuration process. This issue stems from improper privilege management during the certificate handling procedure, specifically when users configure certificates for authentication purposes through the application's graphical interface. The vulnerability is particularly concerning because it leverages the File Open dialog box functionality to execute malicious code with elevated privileges, bypassing normal security boundaries that should prevent local users from gaining administrative access.
The technical flaw manifests in the application's failure to properly drop system privileges after certificate configuration operations. When a local user interacts with the File Open dialog box to select a certificate file, the VPN client maintains elevated privileges that should have been dropped upon completion of the authentication setup process. This privilege retention creates an exploitable condition where malicious actors can manipulate the certificate selection process to execute arbitrary code with system-level permissions. The vulnerability specifically relates to privilege escalation techniques that fall under the CWE-276 category of improper privilege management, where applications fail to properly manage their privilege levels during execution. The underlying mechanism allows attackers to leverage the application's legitimate file browsing functionality to inject malicious certificates that, when processed, trigger privilege escalation.
The operational impact of this vulnerability is significant for organizations relying on the Nortel Contivity VPN client for secure remote access. Local users who can interact with the application's certificate configuration interface can potentially elevate their privileges to system level, enabling them to access sensitive system resources, modify critical files, or establish persistent backdoors within the network infrastructure. This threat vector is particularly dangerous in environments where multiple users share the same system or where users have legitimate access to the VPN client but should not possess administrative privileges. The vulnerability creates a persistent security risk that could be exploited by both insider threats and external attackers who gain local access to systems running the vulnerable VPN client. The attack chain typically involves the local user opening the File Open dialog, selecting a maliciously crafted certificate file, and then executing code with elevated privileges, which aligns with the ATT&CK technique T1068 for privilege escalation.
Mitigation strategies for CVE-2005-2579 should focus on immediate patching of the Nortel Contivity VPN client to the latest secure version that addresses the privilege dropping mechanism. Organizations should also implement strict access controls to limit local user privileges and prevent unauthorized access to the VPN client configuration interface. Network segmentation and monitoring of certificate-related activities can help detect potential exploitation attempts. The vulnerability demonstrates the importance of proper privilege management in security-critical applications and highlights the need for comprehensive security testing of authentication mechanisms. Security administrators should also consider implementing application whitelisting policies to restrict which programs can be executed through the File Open dialog box, thereby limiting the attack surface for privilege escalation attempts. Additionally, regular security assessments should verify that applications properly drop privileges after performing authentication-related operations to prevent similar vulnerabilities from being introduced in future software versions.