CVE-2023-36498 in ER7206 Omada Gigabit VPN Router
Summary
by MITRE • 02/06/2024
A post-authentication command injection vulnerability exists in the PPTP client functionality of Tp-Link ER7206 Omada Gigabit VPN Router 1.3.0 build 20230322 Rel.70591. A specially crafted HTTP request can lead to arbitrary command injection. An attacker can make an authenticated HTTP request to trigger this vulnerability and gain access to an unrestricted shell.
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Analysis
by VulDB Data Team • 03/01/2024
This vulnerability represents a critical post-authentication command injection flaw in the PPTP client implementation of TP-Link ER7206 Omada Gigabit VPN Router firmware version 1.3.0 build 20230322 Rel.70591. The issue stems from inadequate input validation within the router's web interface when processing HTTP requests related to PPTP client configuration. The vulnerability manifests when an authenticated attacker submits a malicious HTTP request that bypasses proper sanitization of user-supplied parameters, allowing arbitrary command execution within the router's operating system context.
The technical exploitation of this vulnerability occurs through the manipulation of HTTP request parameters that are directly passed to underlying system commands without proper filtering or escaping. This type of flaw falls under CWE-77 which specifically addresses command injection vulnerabilities where user-controllable data is incorporated into system commands. The vulnerability's impact is amplified by its post-authentication nature, meaning that an attacker must first establish valid credentials to the router's web interface, but once authenticated, they can execute arbitrary commands with the privileges of the web server process, typically equivalent to root access within the router's confined environment.
The operational implications of this vulnerability are severe as it provides attackers with unrestricted shell access to the affected router, enabling them to execute any command available on the device. This access allows for complete compromise of the router's functionality including but not limited to modifying network configurations, establishing persistent backdoors, capturing network traffic, accessing connected devices, and potentially using the compromised router as a pivot point for further attacks within the local network. The vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under T1059 for command and script execution, and T1021 for remote services, as it enables unauthorized remote command execution through the web interface.
Mitigation strategies should focus on immediate firmware updates from TP-Link to address the command injection flaw, along with implementing network segmentation and access controls to limit exposure. Organizations should also consider disabling unnecessary services like PPTP client functionality when not required, implementing network monitoring to detect unusual command execution patterns, and enforcing strong authentication controls including multi-factor authentication. Additionally, network administrators should conduct regular security assessments of network infrastructure devices to identify similar vulnerabilities and ensure proper patch management procedures are in place to address such issues promptly. The vulnerability highlights the critical importance of input validation and proper sanitization of user-supplied data in web applications, particularly in network infrastructure devices where the potential for system compromise is high.