CVE-2025-45865 in A3002R
Summary
by MITRE • 05/13/2025
TOTOLINK A3002R v4.0.0-B20230531.1404 was discovered to contain a buffer overflow via the dnsaddr parameter in the formDhcpv6s interface.
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Analysis
by VulDB Data Team • 05/26/2025
The vulnerability identified as CVE-2025-45865 represents a critical buffer overflow flaw within the TOTOLINK A3002R router firmware version v4.0.0-B20230531.1404. This issue manifests through the dnsaddr parameter within the formDhcpv6s interface, creating a potential pathway for remote code execution and system compromise. The affected device operates under the TOTOLINK A3002R model which is commonly deployed in residential and small office environments, making it a significant concern for network security. Buffer overflow vulnerabilities of this nature typically occur when a program writes more data to a fixed-length buffer than it can accommodate, leading to memory corruption and potential exploitation. This specific flaw falls under the CWE-121 category of stack-based buffer overflow, where the dnsaddr parameter is processed without adequate bounds checking, allowing attackers to overwrite adjacent memory locations.
The technical implementation of this vulnerability involves the improper handling of user-supplied input through the web interface of the router's management system. When an attacker submits a malformed dnsaddr parameter to the formDhcpv6s endpoint, the firmware fails to validate the input length against the allocated buffer space. This oversight allows for memory corruption that can be exploited to overwrite return addresses, function pointers, or other critical memory segments. The attack surface is particularly concerning as it operates through the standard web management interface, requiring no specialized tools or physical access to the device. The vulnerability's impact extends beyond simple denial of service, as successful exploitation could enable full system compromise, allowing attackers to execute arbitrary code with root privileges. This aligns with ATT&CK technique T1059.007 for command and scripting interpreter, where adversaries can leverage such vulnerabilities to establish persistent access to network infrastructure.
The operational implications of CVE-2025-45865 are severe for organizations and individuals relying on TOTOLINK A3002R devices, as the vulnerability enables remote exploitation without authentication. Network administrators face the challenge of securing devices that may be exposed to the internet, particularly given the prevalence of default configurations that leave management interfaces accessible. The device's DHCPv6 functionality makes it especially vulnerable as this protocol is commonly used in modern network environments, increasing the likelihood of exploitation through legitimate network traffic. Security professionals must consider the potential for lateral movement within networks where these devices are deployed, as compromised routers can serve as launching points for attacks against internal systems. The vulnerability also highlights the importance of firmware update management, as many users may not regularly update their router firmware, leaving them exposed to known exploits. This scenario aligns with ATT&CK technique T1595.001 for network scanning, where attackers can identify vulnerable devices within their target network. Organizations should implement network segmentation to isolate critical infrastructure from potentially compromised devices and establish robust patch management procedures to address such vulnerabilities promptly.
Mitigation strategies for CVE-2025-45865 should prioritize immediate firmware updates from TOTOLINK, if available, or implementation of network-level restrictions to prevent unauthorized access to the router's management interface. Network administrators should disable unnecessary services and ports, particularly those related to DHCPv6 functionality that may not be required in the local environment. Implementing network access control lists to restrict access to the router's management interface to trusted IP addresses can significantly reduce exploitation risk. The use of intrusion detection systems can help identify attempts to exploit this vulnerability through anomalous traffic patterns or malformed requests targeting the affected interface. Regular security assessments of network infrastructure should include verification of router firmware versions and identification of devices running vulnerable software. Organizations should also consider implementing network monitoring to detect unusual DHCPv6 traffic patterns that may indicate exploitation attempts. Physical security measures, such as securing router access points and implementing strong administrative credentials, complement the technical mitigations. The vulnerability underscores the necessity of maintaining current security practices, including regular firmware updates, network segmentation, and continuous monitoring for signs of compromise. Additionally, security teams should develop incident response procedures specifically addressing router compromise scenarios, as these devices often serve as critical network entry points for broader attacks.