CVE-2021-45528 in R6300v2
Summary
by MITRE • 12/26/2021
Certain NETGEAR devices are affected by a buffer overflow by an authenticated user. This affects R6300v2 before 1.0.4.52, R6400 before 1.0.1.52, R6900 before 1.0.2.8, R7000 before 1.0.9.88, R7900 before 1.0.3.18, R8000 before 1.0.4.46, R7900P before 1.4.1.50, R8000P before 1.4.1.50, RAX75 before 1.0.3.88, RAX80 before 1.0.3.88, and WNR3500Lv2 before 1.2.0.62.
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Analysis
by VulDB Data Team • 12/28/2021
This vulnerability represents a critical buffer overflow condition affecting multiple NETGEAR router models that has been classified under CWE-121 as a stack-based buffer overflow. The flaw exists within the web interface management functionality of affected devices, where authenticated users can exploit improper input validation to overwrite adjacent memory locations. The vulnerability is particularly concerning because it requires only authentication credentials to exploit, meaning that an attacker with valid user access can potentially execute arbitrary code on the affected devices. The affected firmware versions span several generations of NETGEAR routers including the R6300v2, R6400, R6900, R7000, R7900, R8000, R7900P, R8000P, RAX75, RAX80, and WNR3500Lv2 models. This vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1068 for exploit for privilege escalation, as it enables authenticated code execution that could be leveraged for further network compromise.
The technical implementation of this buffer overflow occurs within the web server component of the router firmware where user-supplied input is processed without adequate bounds checking. When an authenticated user submits specially crafted data through the web interface, the application fails to validate the length of input parameters before copying them into fixed-size buffers. This allows attackers to overwrite adjacent memory locations, potentially including return addresses or function pointers, which can be manipulated to redirect program execution. The vulnerability is particularly dangerous because it operates within the context of the router's privileged execution environment, meaning successful exploitation could provide attackers with complete control over the device's network operations. The exploitation process typically involves crafting malicious payloads that exceed buffer boundaries and overwrite critical program memory, potentially leading to arbitrary code execution or system crashes that could be leveraged for persistent access.
The operational impact of this vulnerability extends beyond simple device compromise, as affected routers serve as critical network infrastructure components that control traffic flow, authentication, and network security policies. An attacker who successfully exploits this vulnerability could gain complete administrative control over the affected router, potentially enabling them to redirect traffic, modify firewall rules, install malware, or use the device as a pivot point for attacking other systems within the local network. The vulnerability affects devices that are widely deployed in both residential and enterprise environments, making the potential impact significant across multiple threat scenarios. Organizations using these affected devices may experience unauthorized network access, data interception, or complete network disruption. The authentication requirement reduces the attack surface compared to unauthenticated vulnerabilities, but does not eliminate the risk since compromised user credentials are a common attack vector through phishing, credential reuse, or weak authentication practices.
Mitigation strategies should focus on immediate firmware updates to versions that address the buffer overflow condition, with affected devices being updated to the latest available firmware releases from NETGEAR. Network administrators should implement network segmentation and access controls to limit the potential impact of compromised devices, while also monitoring for suspicious network activity that might indicate exploitation attempts. Additional protective measures include disabling unnecessary web management interfaces, implementing strong authentication practices, and regularly auditing device configurations. The vulnerability demonstrates the importance of input validation and proper memory management in embedded systems, as outlined in the OWASP Top Ten and NIST Cybersecurity Framework guidelines. Organizations should also consider implementing intrusion detection systems to monitor for exploitation attempts and establish incident response procedures specifically addressing router compromise scenarios. Regular vulnerability assessments and penetration testing should be conducted to identify similar issues in other network infrastructure components, as buffer overflow vulnerabilities remain a prevalent class of security flaws in network devices.