CVE-2018-21187 in D7800
Summary
by MITRE
Certain NETGEAR devices are affected by a stack-based buffer overflow by an authenticated user. This affects D7800 before 1.0.1.30, R7500 before 1.0.0.122, R7500v2 before 1.0.3.24, 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 that affects multiple NETGEAR wireless routers and networking devices, specifically targeting models including the D7800, R7500 series, R7800, R9000, WNDR3700v4, WNDR4300 series, WNDR4500v3, and WNR2000v5. The vulnerability is classified as a stack-based buffer overflow under CWE-121, which occurs when a program writes data beyond the bounds of a fixed-length buffer located on the stack. This type of vulnerability is particularly dangerous because it can lead to arbitrary code execution and system compromise. The affected devices are vulnerable due to insufficient input validation in their web-based management interfaces, where authenticated users can exploit this flaw to manipulate memory layout and potentially execute malicious code with elevated privileges.
The technical exploitation of this vulnerability requires an authenticated user account with access to the device's web management interface, making it a privilege escalation issue rather than a remote code execution vulnerability. However, the impact remains severe as authenticated attackers can leverage this flaw to gain full control over the affected devices. The buffer overflow occurs during processing of user-supplied input through the web interface, where input validation is inadequate to prevent excessive data from overwriting adjacent memory locations on the stack. This creates opportunities for attackers to overwrite return addresses, function pointers, or other critical memory structures, enabling them to redirect program execution flow and potentially execute arbitrary code. The vulnerability affects firmware versions prior to specific security patches, with each affected model requiring individual version verification to confirm the presence or absence of the fix.
From an operational perspective, this vulnerability poses significant risks to network security and device integrity across enterprise and residential deployments. Network administrators who manage multiple NETGEAR devices are particularly vulnerable since a single compromised device can serve as a foothold for broader network infiltration. The authenticated nature of the exploit means that attackers must first obtain valid credentials, but this is often achievable through social engineering, credential reuse, or other initial compromise techniques. Once exploited, the vulnerability can enable attackers to modify device configurations, install malicious firmware, redirect network traffic, or use the compromised device as a pivot point for attacks on other network segments. The impact extends beyond individual device compromise to potential network-wide disruption, especially in environments where these devices serve as core networking infrastructure components.
Mitigation strategies for this vulnerability primarily focus on immediate firmware updates from NETGEAR, which address the underlying buffer overflow conditions through proper input validation and memory boundary checks. Organizations should prioritize updating all affected device models to their latest firmware versions, particularly those running versions prior to the specified patch releases. Network segmentation and access control measures can provide additional defense-in-depth layers, limiting the potential impact of successful exploitation by restricting unauthorized access to these devices. Regular security audits and vulnerability assessments should include verification of device firmware versions and configuration settings to ensure proper patch management. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically targeting the T1068 - Exploitation for Privilege Escalation tactic, where attackers leverage software vulnerabilities to gain elevated privileges. Additional monitoring should be implemented to detect unusual network traffic patterns or configuration changes that might indicate exploitation attempts, while maintaining detailed logs of administrative access to these devices for forensic analysis purposes.