CVE-2017-15624 in WVR
Summary
by MITRE
TP-Link WVR, WAR and ER devices allow remote authenticated administrators to execute arbitrary commands via command injection in the new-authtype variable in the pptp_server.lua file.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 12/22/2019
The vulnerability CVE-2017-15624 affects TP-Link WVR WAR and ER series devices, representing a critical command injection flaw that enables remote authenticated administrators to execute arbitrary code on affected systems. This vulnerability exists within the pptp_server.lua file where the new-authtype variable is improperly handled, creating a pathway for malicious command execution. The flaw specifically targets the Point-to-Point Tunneling Protocol (PPTP) server implementation, which is commonly used for remote access VPN connections. Attackers with valid administrative credentials can exploit this vulnerability to gain unauthorized control over the affected devices, potentially leading to complete system compromise and unauthorized network access.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the pptp_server.lua script. When the new-authtype parameter is processed, the system fails to properly escape or validate user-supplied input before incorporating it into system commands. This classic command injection vulnerability allows an authenticated attacker to inject malicious commands that are then executed with the privileges of the web server process, typically running with administrative privileges. The vulnerability is classified as CWE-77 based on the Common Weakness Enumeration, which specifically addresses command injection flaws that occur when user-supplied data is directly incorporated into operating system commands without proper sanitization.
From an operational impact perspective, this vulnerability presents significant risk to network security infrastructure as it allows for remote code execution with administrative privileges. An attacker who has gained administrative access through other means can leverage this vulnerability to escalate their privileges further or to establish persistent access to the device. The affected TP-Link devices are commonly deployed in enterprise environments for remote access and network connectivity, making this vulnerability particularly dangerous as it could provide attackers with backdoor access to corporate networks. The exploitation of this vulnerability can result in complete device compromise, data exfiltration, and potential lateral movement within the network infrastructure.
The attack surface for this vulnerability is limited to authenticated administrators who have valid credentials to access the device's web interface or management functions. However, the impact remains severe as the authenticated access requirement does not prevent the exploitation of this vulnerability once credentials are compromised through phishing attacks, credential reuse, or other means. Network defenders should note that this vulnerability aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter, specifically focusing on the execution of system commands through web interfaces. The vulnerability also relates to T1078 Valid Accounts as it requires legitimate administrative credentials to exploit, but once exploited, can provide persistent access to network resources. Organizations should implement immediate mitigations including applying vendor security patches, restricting administrative access to only trusted users, and monitoring for suspicious command execution patterns in system logs.
Mitigation strategies should include immediate deployment of TP-Link security updates and firmware patches that address the command injection vulnerability in the pptp_server.lua file. Network segmentation and access control measures should be implemented to limit administrative access to only necessary personnel with proper authorization. Additionally, organizations should consider disabling PPTP functionality if it is not required for business operations, as this would eliminate the attack vector entirely. Regular security audits and vulnerability assessments should be conducted to identify similar command injection vulnerabilities in other network devices and applications. The implementation of web application firewalls and input validation controls can provide additional defense-in-depth measures against similar command injection attacks. Organizations should also establish monitoring procedures to detect unauthorized command execution attempts and maintain comprehensive incident response plans to address potential exploitation of this vulnerability.