CVE-2024-4164 in Tenda
Summary
by MITRE • 04/25/2024
A vulnerability, which was classified as critical, has been found in Tenda G3 15.11.0.17(9502). This issue affects the function formModifyPppAuthWhiteMac of the file /goform/ModifyPppAuthWhiteMac. The manipulation of the argument pppoeServerWhiteMacIndex leads to stack-based buffer overflow. The attack may be initiated remotely. The exploit has been disclosed to the public and may be used. The associated identifier of this vulnerability is VDB-261983. 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 • 05/29/2024
This critical vulnerability exists in the Tenda G3 router firmware version 15.11.0.17(9502) within the web interface functionality. The flaw resides in the formModifyPppAuthWhiteMac function located in the /goform/ModifyPppAuthWhiteMac file path, representing a stack-based buffer overflow condition that can be exploited through remote manipulation. The vulnerability specifically targets the pppoeServerWhiteMacIndex argument, which when improperly handled allows attackers to overwrite adjacent stack memory locations. This type of buffer overflow represents a CWE-121 vulnerability classification, where insufficient bounds checking permits memory corruption that can lead to arbitrary code execution. The attack vector is remotely accessible, meaning an unauthenticated attacker can exploit this weakness without physical access to the device, making it particularly dangerous in networked environments. The public disclosure of this exploit, tracked under VDB-261983, indicates that threat actors have already developed working payloads against this specific firmware version, increasing the immediate risk to affected users. The lack of vendor response to early disclosure attempts suggests a potential delay in patch development or awareness, leaving users exposed to active exploitation. This vulnerability directly aligns with ATT&CK technique T1210 - Exploitation of Remote Services, as it allows for remote code execution through web interface manipulation. The stack-based nature of the overflow means that successful exploitation could result in complete system compromise, allowing attackers to gain persistent access to the router's administrative functions. The PPPoE authentication white MAC functionality is particularly concerning because it controls which MAC addresses can establish authenticated connections, making this vulnerability potentially devastating for network security. This issue represents a significant risk to home and small office networks where these routers are commonly deployed, as they often serve as the primary gateway to internet connectivity and internal network access.
The technical implementation of this vulnerability demonstrates poor input validation practices within the web application layer of the router firmware. The pppoeServerWhiteMacIndex parameter lacks proper bounds checking, allowing an attacker to provide input that exceeds the allocated buffer space on the stack. When this occurs, adjacent memory locations including return addresses and function pointers become overwritten, potentially allowing an attacker to redirect program execution flow. The stack-based buffer overflow creates a predictable memory corruption pattern that can be exploited through carefully crafted input sequences. This type of vulnerability is classified as a CWE-787, which specifically addresses out-of-bounds write operations that can lead to arbitrary code execution. The exploitation process typically involves crafting a malicious payload that fills the buffer and overflows into the return address, enabling the attacker to execute shellcode or jump to a desired code location within the router's memory space. The remote accessibility of this vulnerability through the web interface means that attackers can leverage this weakness from anywhere on the internet, without requiring local network access or physical presence. The vulnerability's classification as critical by multiple security organizations underscores the severity of potential impact, as successful exploitation could lead to complete device compromise and unauthorized network access.
The operational impact of this vulnerability extends beyond simple device compromise to encompass complete network infrastructure control. Once exploited, attackers can gain administrative access to the router, enabling them to modify network settings, redirect traffic, implement man-in-the-middle attacks, or establish persistent backdoors. The PPPoE authentication functionality being compromised means that attackers could potentially authenticate as legitimate users and gain access to internal network resources. This vulnerability particularly affects users in home and small business environments where routers serve as the primary security boundary between internal networks and the internet. The potential for remote code execution creates a pathway for attackers to deploy malware, establish command and control channels, or use the compromised device as a launch point for attacks against other networked systems. Network traffic interception and modification becomes possible, potentially leading to data theft, session hijacking, or disruption of network services. The lack of vendor response to early disclosure indicates that affected users may remain vulnerable for extended periods without official patches or mitigation guidance. This vulnerability could enable attackers to create persistent access points within networks, making long-term surveillance or data exfiltration possible. The exposure of this vulnerability through public disclosure increases the risk of widespread exploitation, as security researchers and malicious actors alike can leverage the same attack vectors against affected devices.
Mitigation strategies for this vulnerability should include immediate firmware updates from the vendor if available, though the lack of vendor response suggests this may not be forthcoming. Network administrators should implement network segmentation and firewall rules to limit access to affected devices, particularly blocking direct internet access to the router's web interface. The implementation of intrusion detection systems can help identify exploitation attempts by monitoring for unusual traffic patterns or known exploit signatures. Users should disable unnecessary services and features on affected routers, particularly web interfaces that are not actively required for network management. Network monitoring should include checking for unauthorized changes to router configurations or unexpected network traffic patterns that might indicate compromise. The most effective long-term solution involves replacing affected devices with versions that have been patched or updated by the vendor. Security professionals should consider implementing network access control lists that restrict which hosts can communicate with router management interfaces. Regular vulnerability scanning of network infrastructure can help identify other potentially vulnerable devices that may share similar firmware versions or configuration patterns. The lack of vendor response to this vulnerability underscores the importance of maintaining awareness of known issues and having contingency plans in place for unpatched devices. Organizations should consider implementing device inventory tracking to ensure all network-connected devices are accounted for and monitored for similar vulnerabilities. Network administrators should also consider deploying network-based security controls that can detect and block exploitation attempts before they can succeed. The public disclosure of this vulnerability emphasizes the need for proactive security measures rather than reactive responses to known threats.