CVE-2023-7220 in NR1800X
Summary
by MITRE • 01/09/2024
A vulnerability was found in Totolink NR1800X 9.1.0u.6279_B20210910 and classified as critical. Affected by this issue is the function loginAuth of the file /cgi-bin/cstecgi.cgi. The manipulation of the argument password leads to stack-based buffer overflow. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. VDB-249854 is the identifier 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 • 01/25/2024
The vulnerability identified as CVE-2023-7220 represents a critical stack-based buffer overflow flaw in the Totolink NR1800X router firmware version 9.1.0u.6279_B20210910. This vulnerability resides within the loginAuth function of the /cgi-bin/cstecgi.cgi file, which serves as a critical component for authentication handling in the device's web interface. The flaw specifically manifests when processing the password argument, creating an exploitable condition that allows attackers to manipulate memory layout through carefully crafted input. The vulnerability's classification as critical stems from its remote exploitability and the fact that it has been publicly disclosed with an associated VDB identifier of 249854, indicating that threat actors have likely already developed working exploits for this weakness.
The technical implementation of this buffer overflow vulnerability follows established patterns that align with CWE-121 stack-based buffer overflow conditions where insufficient bounds checking allows an attacker to write beyond the allocated buffer space. When the password argument exceeds the predetermined buffer limits, the overflow can overwrite adjacent stack memory locations including return addresses, function pointers, or other critical control data. This memory corruption creates opportunities for arbitrary code execution or system compromise, as the overflow can potentially redirect program execution flow to attacker-controlled code. The attack vector being remote means that exploitation does not require physical access to the device, making the vulnerability particularly dangerous for networked environments where these routers are deployed.
The operational impact of this vulnerability extends beyond simple authentication bypass to potentially enable complete system compromise of affected Totolink NR1800X devices. Successful exploitation could allow attackers to gain administrative privileges, modify router configurations, redirect network traffic, or establish persistent backdoors for continued access. The implications are particularly severe given that many consumer and small office routers serve as primary network gateways, making them attractive targets for attackers seeking to establish footholds within larger networks. The lack of vendor response to early disclosure attempts compounds the risk, as organizations cannot rely on official patches or updates to address the vulnerability, leaving affected systems exposed for extended periods.
Security professionals should immediately implement network segmentation and access controls to limit exposure of affected devices to untrusted networks. The recommended mitigation strategies include disabling unnecessary remote management features, implementing strong network monitoring to detect suspicious authentication attempts, and deploying intrusion detection systems that can identify exploitation attempts targeting this specific vulnerability. Organizations should also consider implementing network access control lists that restrict access to the affected cgi-bin endpoints and ensure that all devices are regularly updated with the latest firmware versions from the vendor. This vulnerability demonstrates the importance of maintaining current security practices and the risks associated with unsupported or unpatched network infrastructure components, particularly when vendor communication fails to address critical security concerns in a timely manner. The vulnerability's alignment with ATT&CK techniques for credential access and privilege escalation highlights the need for comprehensive security monitoring and incident response procedures to detect and respond to exploitation attempts effectively.