CVE-2022-37232 in N300
Summary
by MITRE • 09/23/2022
Netgear N300 wireless router wnr2000v4-V1.0.0.70 is vulnerable to Buffer Overflow via uhttpd. There is a stack overflow vulnerability caused by strcpy.
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Analysis
by VulDB Data Team • 10/22/2022
The vulnerability identified as CVE-2022-37232 affects Netgear N300 wireless routers model WNR2000v4 with firmware version 1.0.0.70 and is classified as a buffer overflow vulnerability within the uhttpd web server component. This issue represents a critical security weakness that could potentially allow remote code execution and unauthorized access to the affected device. The vulnerability stems from improper input validation and memory management practices within the web server implementation, specifically utilizing the dangerous strcpy function without adequate bounds checking. According to CWE-121, this vulnerability falls under stack-based buffer overflow conditions where insufficient bounds checking allows an attacker to overwrite adjacent memory locations on the stack. The uhttpd web server component serves as the primary interface for web-based administration of the router, making this vulnerability particularly dangerous as it could be exploited through web browser interactions. The stack overflow occurs when user-supplied input is copied directly into a fixed-size buffer using strcpy, which does not perform any length validation before copying data. This fundamental flaw in memory management creates an opportunity for attackers to manipulate the program execution flow by overwriting return addresses and other critical stack variables. The vulnerability's impact extends beyond simple denial of service as it can potentially enable full system compromise, allowing attackers to execute arbitrary code with the privileges of the web server process. The attack surface is particularly concerning given that the affected routers are commonly deployed in home and small office environments where network security may be insufficiently managed. The use of strcpy in this context aligns with ATT&CK technique T1210 which involves exploiting weaknesses in remote services to gain initial access. This vulnerability demonstrates a classic example of insecure coding practices that have been widely documented in cybersecurity literature and represents a significant risk to network infrastructure security. The exploitation of such vulnerabilities in consumer-grade networking equipment poses a substantial threat to end-user privacy and network integrity, particularly when these devices are deployed without proper security hardening or regular firmware updates.
The technical exploitation of this buffer overflow vulnerability requires an attacker to craft malicious input that exceeds the allocated buffer size in the uhttpd web server. When the strcpy function processes this oversized input, it continues copying bytes beyond the intended buffer boundaries, eventually overwriting adjacent memory locations including the stack's return address. This memory corruption can be leveraged to redirect program execution to malicious code injected by the attacker. The vulnerability's severity is amplified by the fact that the affected firmware version 1.0.0.70 likely lacks modern security mitigations such as stack canaries, address space layout randomization, or non-executable stack protections. Network administrators should recognize that this vulnerability affects a specific product line and firmware version, making it potentially exploitable through targeted attacks against known vulnerable configurations. The stack overflow condition creates a predictable memory corruption pattern that can be systematically exploited, especially when combined with other techniques such as return-oriented programming or information leakage attacks. The vulnerability's presence in uhttpd, a common embedded web server implementation, suggests that similar issues may exist in other firmware implementations using the same or similar components. This type of vulnerability has been consistently identified in embedded systems and IoT devices, highlighting the need for improved secure coding practices throughout the software development lifecycle. The exploitation of such vulnerabilities often requires minimal network exposure as the web interface is typically accessible from external networks, making these devices prime targets for automated scanning and exploitation campaigns.
Mitigation strategies for CVE-2022-37232 should prioritize immediate firmware updates from Netgear to address the underlying buffer overflow condition. System administrators must ensure that all affected Netgear N300 routers are updated to the latest firmware versions that contain patches for the uhttpd component. When firmware updates are not immediately available, network segmentation and access control measures should be implemented to limit exposure of these devices to untrusted networks. The implementation of network access control lists and firewall rules can help restrict access to the router's web administration interface from external networks. Additionally, disabling unnecessary services and ports on the affected routers can reduce the attack surface and limit potential exploitation vectors. Security monitoring should include detection of unusual network traffic patterns that might indicate exploitation attempts against the vulnerable web server. Organizations should also consider implementing intrusion detection systems that can identify known attack signatures associated with buffer overflow exploitation attempts. The vulnerability's classification under CWE-121 highlights the importance of secure coding practices including the use of safer string handling functions such as strlcpy or snprintf instead of strcpy. Network security teams should develop incident response procedures that account for potential exploitation of this vulnerability, including steps for device isolation and forensic analysis. Regular vulnerability scanning and network monitoring can help identify additional instances of vulnerable devices within the network infrastructure. The exploitation of this vulnerability could potentially enable attackers to establish persistent access to the network, making comprehensive security assessments and network segmentation crucial defensive measures. Organizations should also consider the broader implications of this vulnerability within their overall security posture, particularly in environments where legacy networking equipment remains in use without proper update mechanisms or security controls.