CVE-2024-0999 in N200RE
Summary
by MITRE • 01/29/2024
A vulnerability was found in Totolink N200RE 9.3.5u.6139_B20201216. It has been declared as critical. This vulnerability affects the function setParentalRules of the file /cgi-bin/cstecgi.cgi. The manipulation of the argument eTime leads to stack-based buffer overflow. The attack can be initiated remotely. The exploit has been disclosed to the public and may be used. The identifier of this vulnerability is VDB-252268. NOTE: The vendor was contacted early about this disclosure but did not respond in any way.
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Analysis
by VulDB Data Team • 02/21/2024
The vulnerability identified as CVE-2024-0999 represents a critical stack-based buffer overflow flaw in the Totolink N200RE router firmware version 9.3.5u.6139_B20201216. This issue resides within the web-based administration interface, specifically in the cstecgi.cgi script which handles various router configuration functions. The affected function setParentalRules processes parental control settings and accepts user input through the eTime parameter, creating a dangerous condition where malformed input can overwrite adjacent memory on the stack. The vulnerability manifests when an attacker sends a specially crafted request to the router's web interface, exploiting the improper bounds checking in the eTime argument handling mechanism. This particular flaw falls under CWE-121 Stack-based Buffer Overflow, which is classified as a high-risk vulnerability due to its potential for arbitrary code execution and system compromise. The attack vector is remotely exploitable, meaning an attacker does not require physical access to the device or local network presence to initiate the attack, making it particularly dangerous for networked environments.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as stack-based buffer overflows can lead to complete system compromise and unauthorized access to the router's administrative functions. An attacker who successfully exploits this vulnerability could gain full control over the router's configuration, potentially redirecting traffic, disabling security features, or establishing persistent backdoors for future access. The disclosure of this exploit in the public domain significantly increases the risk to affected users, as demonstrated by the vulnerability database identifier VDB-252268 which indicates active exploitation attempts. The fact that the vendor did not respond to early disclosure attempts suggests either limited resources for security patching or inadequate vulnerability management processes, leaving users without official remediation. This vulnerability aligns with ATT&CK technique T1059.007 Command and Scripting Interpreter: Unix Shell, as exploitation could potentially involve command injection through the compromised router interface. The impact is particularly severe for home and small office networks where these routers are commonly deployed as primary network gateways.
Mitigation strategies for CVE-2024-0999 must be implemented immediately given the public availability of exploit code and the critical severity rating. Users should prioritize firmware updates from Totolink if available, though the vendor's lack of response suggests this may not be forthcoming. Network segmentation through firewalls and access control lists can help limit exposure by preventing remote access to the router's administrative interface from untrusted networks. Administrators should disable remote management features when possible and ensure that the router's web interface is only accessible from trusted internal networks. The implementation of intrusion detection systems can help identify exploitation attempts by monitoring for suspicious requests to the cstecgi.cgi endpoint. Additionally, network administrators should consider disabling unnecessary services and ports, particularly those related to the web interface if they are not actively required. Regular network monitoring for unusual traffic patterns or unauthorized configuration changes can provide early warning of potential exploitation attempts. The vulnerability also highlights the importance of supply chain security and vendor communication, as the lack of vendor response demonstrates the risks associated with embedded device security. Organizations should maintain up-to-date inventories of all network devices and implement regular security assessments to identify similar vulnerabilities in other network infrastructure components. This vulnerability serves as a reminder that even consumer-grade networking equipment can harbor critical flaws that compromise entire network perimeters, making comprehensive security posture management essential.