CVE-2019-19142 in WRN240
Summary
by MITRE
Intelbras WRN240 devices do not require authentication to replace the firmware via a POST request to the incoming/Firmware.cfg URI.
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Analysis
by VulDB Data Team • 09/22/2024
The vulnerability identified as CVE-2019-19142 affects Intelbras WRN240 wireless routers and presents a critical security flaw in the device's firmware update mechanism. This issue stems from the absence of proper authentication requirements when processing firmware replacement requests through the incoming/Firmware.cfg URI endpoint. The vulnerability allows any remote attacker to upload and install malicious firmware without requiring valid credentials or authorization, fundamentally compromising the device's integrity and security posture.
This technical flaw represents a significant bypass of authentication controls that should normally be enforced before allowing firmware modifications. The device's web interface fails to implement proper access control measures, creating an attack vector that aligns with CWE-287 - Improper Authentication. The POST request mechanism to the specific URI endpoint demonstrates a clear lack of input validation and authorization checks that would normally be expected in enterprise networking equipment. The vulnerability exists in the device's firmware update handler, which should require administrative credentials or cryptographic verification before accepting new firmware images.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass complete device compromise and potential network infiltration. An attacker who can successfully exploit this vulnerability gains the ability to install malicious firmware that could provide persistent backdoors, redirect network traffic, or completely disable the device's functionality. This represents a severe escalation from a simple authentication bypass to a full system compromise that could affect the entire network segment the device serves. The vulnerability affects network availability and integrity, as the device could be rendered unusable or repurposed for malicious activities.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1072 - Software Deployment Tools, where adversaries can leverage legitimate administrative tools to install malicious software. The attack surface is particularly concerning given that wireless routers typically serve as gateways between internal networks and the internet, making them prime targets for initial access. Organizations should consider implementing network segmentation strategies and monitoring for unauthorized firmware changes to detect potential exploitation attempts. The vulnerability also demonstrates poor security by design principles, as the device should have implemented robust authentication mechanisms before allowing any firmware modification operations.
Mitigation strategies should include immediate firmware updates from Intelbras if available, network segmentation to limit access to administrative functions, and implementation of intrusion detection systems to monitor for unauthorized firmware upload attempts. Network administrators should also consider disabling unnecessary administrative interfaces and implementing strong access controls for all network devices. The vulnerability highlights the importance of proper security testing and validation of network equipment before deployment, particularly for devices handling firmware updates and administrative functions. Organizations should regularly audit their network infrastructure for similar authentication bypass vulnerabilities and ensure that all devices implement proper authorization mechanisms before allowing critical operations such as firmware replacement.