CVE-2018-21200 in R7800
Summary
by MITRE
Certain NETGEAR devices are affected by a stack-based buffer overflow by an authenticated user. This affects R7800 before 1.0.2.40 and R9000 before 1.0.3.6.
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Analysis
by VulDB Data Team • 06/03/2024
This vulnerability represents a critical stack-based buffer overflow flaw in NETGEAR routers that affects specific models including the R7800 and R9000. The issue arises from insufficient input validation within the device's web interface handling mechanism, allowing an authenticated attacker to exploit this weakness through crafted HTTP requests. The vulnerability exists in firmware versions prior to 1.0.2.40 for R7800 and 1.0.3.6 for R9000, indicating that these devices lack proper bounds checking when processing user-supplied data. The stack-based nature of the overflow means that malicious input can overwrite adjacent memory locations on the program stack, potentially leading to arbitrary code execution or system crashes. This vulnerability falls under CWE-121 Stack-based Buffer Overflow, which is classified as a serious weakness in software security design. The authenticated nature of the exploit requires an attacker to first obtain valid credentials, but once achieved, the attacker can leverage this vulnerability to gain deeper access to the device's underlying system.
The operational impact of this vulnerability extends beyond simple system instability as it provides a pathway for attackers to execute arbitrary commands on the affected devices. When an authenticated user submits malicious input through the web interface, the buffer overflow can be triggered to overwrite return addresses and function pointers stored on the stack. This memory corruption can result in the device crashing or potentially allow an attacker to inject and execute malicious code within the router's operating environment. The exploitation of this vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1068 for Exploitation for Privilege Escalation, as attackers can leverage the authenticated access to escalate their privileges and gain unauthorized control over the network infrastructure. Network administrators face significant risk as compromised routers can serve as entry points for broader network infiltration, potentially enabling man-in-the-middle attacks, DNS hijacking, or serving as a pivot point for attacking other networked devices.
Mitigation strategies for this vulnerability require immediate firmware updates to versions 1.0.2.40 for R7800 and 1.0.3.6 for R9000, which contain patches addressing the buffer overflow conditions. Organizations should also implement network segmentation to limit the potential impact if a device is compromised, and establish robust credential management practices to prevent unauthorized access. Additional protective measures include disabling unnecessary services, implementing strong authentication mechanisms, and monitoring network traffic for suspicious activity patterns that might indicate exploitation attempts. Security teams should conduct thorough vulnerability assessments of their network infrastructure to identify all affected devices and ensure proper patch management procedures are in place. The vulnerability demonstrates the importance of proper input validation and memory management practices in embedded systems, aligning with security best practices outlined in NIST SP 800-160 and ISO/IEC 27001 standards. Regular security audits and firmware update schedules are essential to maintain device security posture and prevent exploitation of similar vulnerabilities in the future.