CVE-2018-21173 in R7500
Summary
by MITRE
Certain NETGEAR devices are affected by a stack-based buffer overflow by an authenticated user. This affects R7500 before 1.0.0.122, R7800 before 1.0.2.40, R9000 before 1.0.2.52, WNDR3700v4 before 1.0.2.92, WNDR4300 before 1.0.2.94, WNDR4300v2 before 1.0.0.50, WNDR4500v3 before 1.0.0.50, and WNR2000v5 before 1.0.0.62.
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Analysis
by VulDB Data Team • 06/03/2024
This vulnerability represents a critical stack-based buffer overflow flaw in NETGEAR router firmware that enables authenticated users to execute arbitrary code remotely. The vulnerability affects multiple router models including R7500, R7800, R9000, and various WNDR series devices, with specific version ranges indicating the scope of affected firmware implementations. The stack-based buffer overflow occurs when the device processes user-supplied input without proper bounds checking, allowing an authenticated attacker to overwrite adjacent memory locations on the stack. This type of vulnerability falls under CWE-121 which specifically addresses stack-based buffer overflow conditions, where insufficient boundary checking allows attackers to overwrite stack data and potentially gain control over the device's execution flow. The vulnerability is particularly dangerous because it requires only authentication to the device's web interface, which is typically accessible to any user who knows the admin credentials or has access to the network. The operational impact of this vulnerability extends beyond simple code execution to include complete device compromise, potential network infiltration, and unauthorized access to sensitive data flowing through the compromised router. Attackers could leverage this vulnerability to install malware, redirect traffic, or establish persistent backdoors within the network infrastructure. The affected devices operate under the assumption that authenticated users can be trusted, which creates a dangerous attack surface where legitimate administrative access can be exploited to escalate privileges and gain root-level control. This vulnerability aligns with ATT&CK technique T1059 which covers command and scripting interpreter usage, as the compromised device could be used to execute malicious commands. The exploitation process typically involves crafting malicious input that exceeds the buffer size, causing a stack overflow that can be manipulated to redirect program execution to attacker-controlled code. Network reconnaissance and privilege escalation activities become significantly easier once an attacker gains this level of access to the router, as they can modify routing tables, intercept traffic, or disable security features. The affected firmware versions suggest that this was a widespread issue across multiple generations of NETGEAR routers, indicating a fundamental flaw in the input validation mechanisms of the affected software implementations. This vulnerability demonstrates the importance of proper input validation and memory management practices in embedded systems, particularly those handling user input through web interfaces. The security implications are compounded by the fact that these routers often serve as the primary gateway for home and small office networks, making their compromise particularly damaging to overall network security posture. Organizations should immediately implement firmware updates to address this vulnerability and conduct thorough network assessments to identify any potential exploitation attempts. The vulnerability also highlights the need for regular security audits of embedded systems and the importance of implementing robust input sanitization measures to prevent similar issues from occurring in future firmware releases.
This vulnerability represents a critical stack-based buffer overflow flaw in NETGEAR router firmware that enables authenticated users to execute arbitrary code remotely. The vulnerability affects multiple router models including R7500, R7800, R9000, and various WNDR series devices, with specific version ranges indicating the scope of affected firmware implementations. The stack-based buffer overflow occurs when the device processes user-supplied input without proper bounds checking, allowing an authenticated attacker to overwrite adjacent memory locations on the stack. This type of vulnerability falls under CWE-121 which specifically addresses stack-based buffer overflow conditions, where insufficient boundary checking allows attackers to overwrite stack data and potentially gain control over the device's execution flow. The vulnerability is particularly dangerous because it requires only authentication to the device's web interface, which is typically accessible to any user who knows the admin credentials or has access to the network. The operational impact of this vulnerability extends beyond simple code execution to include complete device compromise, potential network infiltration, and unauthorized access to sensitive data flowing through the compromised router. Attackers could leverage this vulnerability to install malware, redirect traffic, or establish persistent backdoors within the network infrastructure. The affected devices operate under the assumption that authenticated users can be trusted, which creates a dangerous attack surface where legitimate administrative access can be exploited to escalate privileges and gain root-level control. This vulnerability aligns with ATT&CK technique T1059 which covers command and scripting interpreter usage, as the compromised device could be used to execute malicious commands. The exploitation process typically involves crafting malicious input that exceeds the buffer size, causing a stack overflow that can be manipulated to redirect program execution to attacker-controlled code. Network reconnaissance and privilege escalation activities become significantly easier once an attacker gains this level of access to the router, as they can modify routing tables, intercept traffic, or disable security features. The affected firmware versions suggest that this was a widespread issue across multiple generations of NETGEAR routers, indicating a fundamental flaw in the input validation mechanisms of the affected software implementations. This vulnerability demonstrates the importance of proper input validation and memory management practices in embedded systems, particularly those handling user input through web interfaces. The security implications are compounded by the fact that these routers often serve as the primary gateway for home and small office networks, making their compromise particularly damaging to overall network security posture. Organizations should immediately implement firmware updates to address this vulnerability and conduct thorough network assessments to identify any potential exploitation attempts. The vulnerability also highlights the need for regular security audits of embedded systems and the importance of implementing robust input sanitization measures to prevent similar issues from occurring in future firmware releases.