CVE-2019-11535 in RE6300
Summary
by MITRE
Unsanitized user input in the web interface for Linksys WiFi extender products (RE6400 and RE6300 through 1.2.04.022) allows for remote command execution. An attacker can access system OS configurations and commands that are not intended for use beyond the web UI.
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Analysis
by VulDB Data Team • 07/08/2020
The vulnerability identified as CVE-2019-11535 represents a critical security flaw in Linksys WiFi extender products including the RE6400 and RE6300 models through firmware version 1.2.04.022. This issue stems from improper input validation within the web interface component of these networking devices, creating a pathway for remote attackers to execute arbitrary commands on the underlying operating system. The flaw manifests when user-provided data is not adequately sanitized before being processed by the device's web server, allowing malicious inputs to bypass intended security boundaries and gain access to system-level functionalities that should remain restricted to authorized administrative users.
The technical implementation of this vulnerability aligns with CWE-74, which describes improper neutralization of special elements used in data queries, and CWE-94, which addresses improper control of generation of code. The web interface of these devices fails to properly validate and sanitize user inputs submitted through various form fields and parameters, enabling attackers to inject malicious commands that get executed within the context of the device's operating system. This misconfiguration creates a command injection vulnerability that allows an attacker to leverage the device's web server to execute arbitrary system commands, potentially gaining access to sensitive configuration files, network settings, and other system resources that should remain protected.
From an operational perspective, this vulnerability presents a significant risk to network security and device integrity. An attacker who successfully exploits this flaw can remotely execute commands on the affected devices, potentially leading to complete compromise of the WiFi extender's functionality. The implications extend beyond simple unauthorized access, as the attacker gains visibility into the device's operating system and can manipulate network configurations, access stored credentials, or even use the compromised device as a pivot point for attacking other systems within the local network. This vulnerability particularly affects enterprise and home networks where these devices are commonly deployed, as they often serve as critical components in extending wireless network coverage and managing network access.
The attack surface for this vulnerability is particularly concerning given that the exploitation requires no authentication and can be performed remotely over the network. Attackers can leverage this flaw through the standard web interface of the device, making it accessible to anyone who can reach the device's IP address and port. The vulnerability is classified under the MITRE ATT&CK framework as a command injection technique, specifically mapping to T1059.001 for command and script injection, and potentially T1068 for exploit for privilege escalation once initial access is achieved. Organizations should consider implementing network segmentation and monitoring for unusual network traffic patterns that may indicate exploitation attempts. The recommended mitigation strategy involves immediate firmware updates from Linksys to address the input sanitization issues, along with network monitoring to detect potential exploitation attempts. Additionally, network administrators should consider disabling remote management features when not actively needed and implementing firewall rules to restrict access to the device's web interface to trusted IP addresses only, thereby reducing the attack surface and limiting potential exploitation opportunities.