CVE-2024-7333 in N350RT
Summary
by MITRE • 08/01/2024
A vulnerability was found in TOTOLINK N350RT 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 week/sTime/eTime leads to 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-273256. 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 • 08/09/2024
The vulnerability identified as CVE-2024-7333 represents a critical buffer overflow flaw in the TOTOLINK N350RT router firmware version 9.3.5u.6139_B20201216. This issue resides within the cstecgi.cgi script which serves as a core component for managing various router configuration parameters through web-based interfaces. The specific function setParentalRules handles parental control settings and exposes a dangerous buffer overflow condition when processing the week/sTime/eTime parameters. This type of vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The attack vector is remotely exploitable, meaning an unauthenticated attacker can initiate the attack from outside the local network without requiring physical access or prior authentication to the device.
The technical implementation of this vulnerability demonstrates a classic buffer overflow scenario where user-supplied input parameters are directly processed without adequate validation or length checking. When an attacker sends malicious data to the week/sTime/eTime arguments, the system fails to properly validate the input length, allowing the attacker to overflow the allocated buffer space and potentially overwrite critical memory segments including return addresses, function pointers, or other control data. This memory corruption can lead to arbitrary code execution, system crashes, or complete device compromise. The vulnerability's classification as critical indicates that successful exploitation could result in full system control, data exfiltration, or persistent backdoor installation, making it particularly dangerous for home and small office network environments where such devices are commonly deployed. The fact that the exploit has been publicly disclosed and is actively being used increases the risk to unpatched devices significantly.
The operational impact of this vulnerability extends beyond simple device compromise to encompass broader network security implications. As a router running firmware version 9.3.5u.6139_B20201216, the TOTOLINK N350RT serves as a critical gateway for network traffic, making it an attractive target for attackers seeking persistent access to entire local networks. Once compromised, the device can be used as a pivot point for lateral movement, DNS poisoning, man-in-the-middle attacks, or as a command and control node for botnet activities. The vulnerability affects the parental control functionality specifically, but due to the nature of buffer overflows, attackers may be able to leverage this to gain access to other system functions or even the underlying operating system. The lack of vendor response to early disclosure attempts creates additional concern, as users have no assurance of receiving timely patches or security updates for this device. This situation aligns with ATT&CK technique T1072, where adversaries use compromised network devices to maintain persistent access and expand their attack surface.
Mitigation strategies for CVE-2024-7333 should prioritize immediate network segmentation and access control measures while awaiting potential vendor patches or firmware updates. Network administrators should implement firewall rules to restrict access to the affected router's web interface from untrusted networks and consider disabling the parental control functionality if not essential for operations. The most effective long-term solution involves updating to a firmware version that addresses this buffer overflow vulnerability, though the vendor's lack of response suggests users may need to seek alternative security measures. Organizations should consider implementing network monitoring to detect suspicious traffic patterns that might indicate exploitation attempts, such as unusual data flows or repeated connection attempts to the affected CGI endpoint. Additionally, regular security audits of network infrastructure should include identification and remediation of similar vulnerable devices, as this vulnerability demonstrates a pattern of insufficient input validation in web-based administrative interfaces. The vulnerability serves as a reminder of the importance of maintaining up-to-date firmware and the risks associated with devices that receive no vendor support for security issues.