CVE-2024-7334 in EX1200L
Summary
by MITRE • 08/01/2024
A vulnerability was found in TOTOLINK EX1200L 9.3.5u.6146_B20201023. It has been rated as critical. This issue affects the function UploadCustomModule of the file /cgi-bin/cstecgi.cgi. The manipulation leads to buffer overflow. The attack may be initiated remotely. The exploit has been disclosed to the public and may be used. The identifier VDB-273257 was assigned to this vulnerability. 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-2024-7334 represents a critical buffer overflow flaw within the TOTOLINK EX1200L router firmware version 9.3.5u.6146_B20201023. This issue resides in the UploadCustomModule function of the /cgi-bin/cstecgi.cgi component, which serves as a critical interface for router administration and configuration. The buffer overflow vulnerability occurs when the device processes user-supplied data during the module upload process, creating an exploitable condition that can be leveraged by remote attackers without requiring authentication. The vulnerability's classification as critical stems from its remote exploitability and the potential for arbitrary code execution on the affected device, making it a significant threat to network security infrastructure.
The technical implementation of this buffer overflow vulnerability follows CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. In this specific case, the vulnerability manifests when the UploadCustomModule function fails to properly validate the size of incoming data before copying it into a fixed-size buffer. The attack vector is remote, meaning an adversary can exploit this flaw from outside the local network, potentially enabling unauthorized access to the router's administrative interface. The disclosed exploit code in VDB-273257 demonstrates how an attacker can craft malicious input to overflow the buffer and potentially execute arbitrary commands with the privileges of the web server process, which typically runs with elevated permissions on the router.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass complete network compromise and persistent backdoor access. According to ATT&CK framework technique T1059.007, an attacker could leverage this vulnerability to establish persistent access through command and scripting interpreter techniques, potentially installing malware or creating reverse shells. The affected TOTOLINK EX1200L device serves as a gateway for network traffic, making successful exploitation a critical threat to entire network perimeters. The vulnerability's disclosure without vendor response creates a particularly dangerous scenario where organizations remain exposed to known exploits with no official patch or mitigation guidance available. Network administrators face the challenge of securing devices that are no longer receiving vendor support for this critical flaw, leaving them vulnerable to exploitation by threat actors who may be actively scanning for these specific vulnerable devices.
Mitigation strategies for CVE-2024-7334 should prioritize immediate network segmentation and access control measures to limit exposure. Organizations should implement network monitoring to detect anomalous traffic patterns associated with exploitation attempts, particularly targeting the /cgi-bin/cstecgi.cgi endpoint. The most effective long-term solution involves firmware updates from the vendor, though the lack of vendor response creates an urgent need for alternative security measures. Network administrators should consider disabling unnecessary services and implementing strict firewall rules to prevent external access to the router's administrative interfaces. Additionally, implementing intrusion detection systems with signatures for known exploit patterns and conducting regular vulnerability scanning of network infrastructure can help identify devices running vulnerable firmware versions. The absence of vendor response underscores the importance of maintaining updated security knowledge bases and implementing proactive threat hunting strategies to identify and remediate similar vulnerabilities across the network infrastructure.