CVE-2017-12568 in Embedded httpd
Summary
by MITRE
Denial of Service vulnerability in Debut embedded httpd 1.20 in Brother DCP-J132W (and probably other DCP models) allows remote attackers to hang the printer (disrupting its network connection) by sending a large amount of HTTP packets.
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Analysis
by VulDB Data Team • 11/03/2019
The CVE-2017-12568 vulnerability represents a critical denial of service flaw affecting the embedded httpd web server component version 1.20 found in Brother DCP-J132W multifunction printers and potentially other models within the DCP series. This vulnerability exposes the printer's network functionality to remote exploitation, creating a significant security risk for organizations relying on these devices for document processing and network communication. The flaw specifically targets the embedded web server implementation that handles HTTP requests, making it accessible to attackers who can manipulate the device's network connectivity through carefully crafted HTTP traffic patterns.
The technical nature of this vulnerability stems from inadequate input validation and resource management within the embedded httpd server implementation. When remote attackers send a large volume of HTTP packets to the affected printer, the device becomes overwhelmed and enters a state where it cannot properly process subsequent network requests. This behavior manifests as the printer hanging or becoming unresponsive, effectively disrupting its network connection and rendering the device incapable of performing its intended functions. The vulnerability demonstrates poor defensive programming practices where the system fails to implement proper rate limiting, packet size validation, or resource allocation controls that would prevent a single malicious request from consuming all available processing capacity.
From an operational impact perspective, this vulnerability creates substantial disruption for users and organizations that depend on Brother multifunction printers for their daily operations. Network connectivity issues resulting from the denial of service can halt printing operations, prevent document scanning, and disrupt fax functionality across the entire network. The remote nature of the attack means that malicious actors can exploit this vulnerability from outside the local network perimeter, potentially affecting organizations with printers connected to the internet or those that have not properly isolated their network devices. This vulnerability particularly affects environments where printer security is not prioritized, as many organizations may not regularly update firmware or implement proper network segmentation for networked printing devices.
The vulnerability aligns with CWE-400, which addresses "Uncontrolled Resource Consumption" and specifically relates to the lack of proper resource management in the embedded web server implementation. From an ATT&CK framework perspective, this vulnerability maps to the T1499.004 technique related to "Endpoint Denial of Service" and represents a classic example of how IoT and networked device vulnerabilities can be exploited to create service disruption. Organizations should consider this vulnerability as part of a broader attack surface assessment that includes all networked devices, particularly those with embedded web servers or HTTP interfaces. The lack of proper input validation and resource management in embedded systems represents a common pattern in IoT device security that requires comprehensive security controls including regular firmware updates, network segmentation, and monitoring for anomalous network traffic patterns that could indicate exploitation attempts.
Mitigation strategies should include immediate firmware updates from Brother to address the vulnerability, network segmentation to isolate affected printers from critical systems, and implementation of network monitoring to detect unusual traffic patterns that may indicate exploitation attempts. Organizations should also consider disabling unnecessary network services on printers and implementing proper access controls to prevent unauthorized remote access to printer web interfaces. The vulnerability highlights the importance of treating networked printing devices as security-critical components within enterprise environments and implementing comprehensive device management policies that include regular security assessments and update schedules.