CVE-2017-15629 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-tunnelname variable in the pptp_client.lua file.
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Analysis
by VulDB Data Team • 12/22/2019
The vulnerability CVE-2017-15629 represents a critical command injection flaw affecting TP-Link WVR WAR and ER series network devices. This issue resides within the pptp_client.lua file where the new-tunnelname variable fails to properly sanitize user input, creating an avenue for remote authenticated attackers to execute arbitrary system commands. The vulnerability specifically targets administrators who have legitimate access to the device's management interface, making it particularly dangerous as it leverages existing administrative privileges to escalate attacks. The flaw demonstrates a classic lack of input validation and sanitization that has been documented in numerous security frameworks including CWE-77 and CWE-94, which categorize command injection as a severe weakness in software design.
The technical exploitation of this vulnerability occurs through the manipulation of the new-tunnelname parameter within the pptp_client.lua script. When an authenticated administrator submits a crafted value containing shell metacharacters or command separators, the system fails to properly escape or validate the input before processing it within a shell context. This allows attackers to inject malicious commands that execute with the privileges of the web server process, typically running with administrative rights on the device. The attack vector is particularly concerning because it requires only authentication, not exploitation of additional vulnerabilities, making it accessible to insiders or attackers who have gained administrative credentials through other means.
The operational impact of CVE-2017-15629 extends beyond simple command execution, as it provides attackers with complete control over affected devices. Once exploited, adversaries can access the device's underlying operating system, modify network configurations, install malicious software, or use the compromised device as a pivot point for attacking other systems within the network. This vulnerability directly maps to ATT&CK technique T1059.001 for command and scripting interpreter and T1068 for exploit for privilege escalation, as it enables attackers to leverage existing administrative access to achieve further system compromise. The implications are particularly severe for network infrastructure devices, as they often serve as central points of control and can provide access to sensitive network segments.
Mitigation strategies for this vulnerability should focus on immediate remediation through firmware updates from TP-Link, as the vendor has released patches addressing the command injection flaw. Organizations should also implement network segmentation to limit access to administrative interfaces, enforce strong authentication controls, and monitor for unusual command execution patterns. Additional protective measures include implementing web application firewalls to detect and block malicious input patterns, conducting regular security assessments of network infrastructure, and establishing strict access control policies that limit administrative privileges to only necessary personnel. The vulnerability highlights the importance of input validation and output encoding practices, aligning with security standards such as OWASP Top 10 and NIST guidelines for secure coding practices, particularly those addressing injection flaws and privilege management.