CVE-2018-10900 in Network Manager VPNC Plugin
Summary
by MITRE
Network Manager VPNC plugin (aka networkmanager-vpnc) before version 1.2.6 is vulnerable to a privilege escalation attack. A new line character can be used to inject a Password helper parameter into the configuration data passed to VPNC, allowing an attacker to execute arbitrary commands as root.
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Analysis
by VulDB Data Team • 12/07/2024
The vulnerability identified as CVE-2018-10900 affects the Network Manager VPNC plugin version 1.2.6 and earlier, representing a critical privilege escalation flaw that exploits command injection mechanisms within the network configuration processing pipeline. This vulnerability resides in the handling of configuration data passed to the VPNC client component, where improper input validation allows malicious actors to manipulate the configuration parameters through crafted input containing new line characters. The flaw specifically targets the Password helper parameter injection mechanism, which is designed to handle authentication credentials but becomes exploitable when attackers can inject additional commands through the configuration parsing process. The vulnerability demonstrates characteristics consistent with CWE-77 and CWE-78 classification, where command injection occurs due to insufficient sanitization of user-supplied data that gets processed in a shell context. The attack vector involves an unprivileged user who can manipulate network configuration data to inject malicious command sequences, effectively bypassing normal access controls and executing arbitrary code with root privileges.
The technical implementation of this vulnerability leverages the way the Network Manager VPNC plugin processes configuration parameters, particularly when handling authentication information. When a user configures a VPN connection through Network Manager, the plugin receives configuration data that includes password helper specifications and other authentication parameters. The vulnerability occurs because the plugin does not properly sanitize new line characters or other special characters that could be interpreted as command separators within the configuration processing flow. An attacker can craft a malicious configuration string containing a new line character followed by a command that gets executed with elevated privileges. This type of injection attack directly aligns with ATT&CK technique T1059.001 for command and scripting interpreter, specifically targeting the execution of commands through the vpnc binary which runs with root privileges. The vulnerability is particularly dangerous because it allows attackers to execute arbitrary commands as root without requiring direct access to the system, making it a significant concern for network administrators and system security teams who rely on Network Manager for VPN configuration management.
The operational impact of CVE-2018-10900 extends beyond simple privilege escalation, as it provides attackers with persistent access to compromised systems through the VPN configuration interface. Once exploited, attackers can establish backdoors, modify network settings, exfiltrate data, or pivot to other systems within the network infrastructure. The vulnerability affects systems where Network Manager VPNC plugin is installed and actively used for VPN connections, particularly in enterprise environments where network configuration management is centralized through Network Manager. The attack requires minimal privileges to execute, as users with basic network configuration access can exploit this vulnerability, making it particularly dangerous in multi-user environments. Security professionals must consider this vulnerability as part of broader network security assessments, as it can serve as a foothold for more extensive attacks. The impact is further amplified by the fact that the vulnerability can be exploited through legitimate network configuration interfaces, making detection more challenging and potentially allowing attackers to remain undetected for extended periods. Organizations should implement immediate mitigations including patching to version 1.2.6 or later, which addresses the input validation issues in the configuration processing pipeline. Additionally, network segmentation, monitoring of network configuration changes, and implementation of least privilege principles for network management functions can help reduce the attack surface and limit the potential impact of such vulnerabilities. The vulnerability also highlights the importance of proper input validation and parameter sanitization in network management applications, emphasizing the need for security considerations in the development of system management tools that handle privileged operations.