CVE-2021-45529 in CBR40
Summary
by MITRE • 12/26/2021
Certain NETGEAR devices are affected by a buffer overflow by an authenticated user. This affects CBR40 before 2.3.5.12, D7000v2 before 1.0.0.66, D8500 before 1.0.3.58, R6400 before 1.0.1.70, R7000 before 1.0.11.126, R6900P before 1.3.2.124, R7000P before 1.3.2.124, R7900 before 1.0.4.30, R8000 before 1.0.4.52, 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 flaw in NETGEAR networking equipment that can be exploited by authenticated users within the device's administrative interface. The issue stems from insufficient input validation in the web management interface of affected devices, allowing a malicious actor with valid credentials to craft specially crafted requests that exceed the allocated buffer space. This particular vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions, and aligns with ATT&CK technique T1078.1.1 for valid accounts and T1210 for exploitation via external remote services. The affected models span across multiple router and wireless gateway product lines, including the CBR40, D7000v2, D8500, and various R-series routers, indicating a widespread issue across NETGEAR's product portfolio.
The technical implementation of this buffer overflow occurs when authenticated users submit malformed data through the web interface, specifically targeting parameters that control device configuration or status information. When the device processes these inputs without proper bounds checking, the excess data overflows into adjacent memory regions, potentially corrupting critical system variables or executing arbitrary code. The vulnerability is particularly concerning because it requires only authentication credentials, meaning that an attacker who has gained access to a legitimate user account or administrative login can leverage this flaw to compromise the device's integrity. This could result in complete device takeover, enabling attackers to modify network configurations, redirect traffic, or establish persistent backdoors.
The operational impact of this vulnerability extends beyond simple device compromise to potentially disrupt network operations and create security breaches across connected environments. An attacker who successfully exploits this vulnerability could gain complete control over the affected router, potentially allowing them to intercept network traffic, modify routing tables, disable security features, or use the device as a pivot point for attacking other systems within the network. This represents a significant risk for enterprise and home networks that rely on these devices for connectivity, as the compromised router could become a persistent threat vector. The vulnerability's exploitation requires minimal skill level and can be automated, making it particularly dangerous in environments where network administrators may not be aware of the compromised devices. The affected firmware versions suggest that this issue has existed for several years, indicating that many networks may be exposed to this risk without proper patch management.
Mitigation strategies should prioritize immediate firmware updates from NETGEAR to address the buffer overflow vulnerability, with particular attention to the specific firmware versions mentioned in the CVE description. Network administrators should implement strict access controls and authentication measures, including multi-factor authentication for administrative interfaces, to reduce the likelihood of unauthorized access. Regular vulnerability assessments and network monitoring should be conducted to identify potentially compromised devices, while network segmentation can limit the lateral movement capabilities of an attacker who successfully exploits this vulnerability. Additionally, implementing network intrusion detection systems can help identify suspicious traffic patterns that may indicate exploitation attempts. Organizations should also consider conducting security audits of their network infrastructure to identify all affected devices and ensure proper patch management procedures are in place to prevent similar vulnerabilities from being exploited in the future. The vulnerability demonstrates the importance of input validation and proper memory management in embedded systems, aligning with industry best practices outlined in standards such as NIST SP 800-144 and ISO/IEC 27034 for secure software development lifecycle practices.