CVE-2024-1002 is a critical security vulnerability identified in the Totolink N200RE router, specifically version 9.3.5u.6139_B20201216. The flaw exists in the setIpPortFilterRules function within the /cgi-bin/cstecgi.cgi file. This function improperly handles the ePort argument, leading to a stack-based buffer overflow (CWE-121). A buffer overflow occurs when data exceeds the allocated buffer size, overwriting adjacent memory, which can result in arbitrary code execution, system crashes, or privilege escalation. This vulnerability is exploitable remotely over the network without user interaction, but it requires high privileges (PR:H) on the device to launch the attack. The CVSS 3.1 base score is 7.2, indicating a high severity level with impacts on confidentiality, integrity, and availability. The vulnerability allows an attacker to potentially execute arbitrary code with elevated privileges, compromising the router’s firmware and network traffic. The vendor has not responded to disclosure attempts, and no official patches or mitigations have been released. Although no known exploits are currently observed in the wild, the public disclosure of the exploit code increases the risk of exploitation by threat actors. Given the critical role of routers in network infrastructure, exploitation could lead to network disruption, interception of sensitive data, or use of the device as a pivot point for further attacks within an organization’s network.

For European organizations, this vulnerability poses significant risks due to the widespread use of Totolink N200RE routers in small to medium enterprises and possibly home office environments. Successful exploitation could lead to unauthorized access to internal networks, interception or manipulation of sensitive communications, and disruption of business operations. The compromise of network infrastructure devices like routers can undermine the confidentiality and integrity of data flows, potentially violating GDPR requirements for data protection. Additionally, the availability impact could disrupt critical services relying on network connectivity. The lack of vendor response and patches increases the window of exposure, forcing organizations to consider alternative mitigations or device replacements. Attackers could leverage this vulnerability to establish persistent footholds, conduct lateral movement, or launch further attacks against connected systems, amplifying the threat landscape for European entities.

Since no official patch is available, European organizations should take immediate practical steps to mitigate risk: 1) Identify and inventory all Totolink N200RE devices running the affected firmware version. 2) Restrict administrative access to the router’s management interface by limiting it to trusted IP addresses and using VPNs or secure management channels. 3) Disable remote management features if not strictly necessary to reduce the attack surface. 4) Monitor network traffic and device logs for unusual activity indicative of exploitation attempts, such as unexpected CGI requests targeting /cgi-bin/cstecgi.cgi. 5) Consider network segmentation to isolate vulnerable devices from critical infrastructure and sensitive data. 6) Where possible, replace affected devices with models from vendors that provide timely security updates and have a strong security track record. 7) Employ intrusion detection/prevention systems (IDS/IPS) tuned to detect buffer overflow exploit patterns targeting this router. 8) Educate IT staff about this vulnerability and the importance of rapid response to emerging threats. These steps go beyond generic advice by focusing on access control, monitoring, and device lifecycle management specific to this vulnerability and product.