CVE-2019-20765 in R7800
Summary
by MITRE
NETGEAR R7800 devices before 1.0.2.52 are affected by a stack-based buffer overflow by an authenticated user.
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Analysis
by VulDB Data Team • 05/31/2024
The vulnerability identified as CVE-2019-20765 affects NETGEAR R7800 wireless routers running firmware versions prior to 1.0.2.52, representing a critical stack-based buffer overflow flaw that can be exploited by authenticated users within the device's administrative interface. This vulnerability resides in the router's web management portal where user input is processed without adequate bounds checking, creating an exploitable condition that allows attackers with valid login credentials to execute arbitrary code on the affected device. The flaw manifests when the device processes certain input parameters through its web interface, specifically within the configuration handling routines that manage user-supplied data.
From a technical perspective, this buffer overflow vulnerability stems from improper input validation mechanisms within the router's firmware codebase, where character arrays are written beyond their allocated memory boundaries. The vulnerability is classified as a stack-based buffer overflow according to CWE-121, which occurs when data is copied into a stack buffer without proper bounds checking, allowing adjacent memory locations to be overwritten. Attackers can leverage this flaw by crafting malicious input parameters that exceed the buffer capacity, potentially overwriting return addresses and function pointers on the stack, thereby enabling arbitrary code execution. The authenticated nature of the attack means that an attacker must first obtain valid administrative credentials, typically through social engineering, credential reuse, or other initial compromise techniques, before exploiting this vulnerability.
The operational impact of CVE-2019-20765 extends beyond simple code execution, as it provides attackers with complete control over the affected router, enabling them to modify network configurations, redirect traffic, establish backdoors, or use the device as a pivot point for further attacks within the network. This vulnerability directly impacts the device's integrity and availability, potentially allowing attackers to disrupt network services or create persistent access points. The attack vector aligns with ATT&CK technique T1059.001 for command and scripting interpreter and T1071.001 for application layer protocol, as attackers can leverage the compromised device to execute commands and manipulate network traffic. Network administrators face significant risks as the compromised device can be used to monitor network communications, inject malicious traffic, or serve as a launchpad for attacks against other systems within the local network.
Mitigation strategies for this vulnerability require immediate firmware updates to version 1.0.2.52 or later, which contain patches addressing the buffer overflow condition through proper input validation and bounds checking mechanisms. Network segmentation and access control measures should be implemented to limit administrative access to only authorized personnel, while regular credential rotation and multi-factor authentication can reduce the risk of unauthorized access. Monitoring for unusual administrative activities and network traffic patterns can help detect potential exploitation attempts, and network intrusion detection systems should be configured to alert on suspicious HTTP requests that may indicate buffer overflow exploitation attempts. Additionally, implementing network access controls through firewalls to restrict access to the router's administrative interface from untrusted networks provides an additional layer of protection against potential exploitation attempts.