CVE-2016-1303 in Small Business 500
Summary
by MITRE
The web GUI on Cisco Small Business 500 devices 1.2.0.92 allows remote attackers to cause a denial of service via a crafted HTTP request, aka Bug ID CSCul65330.
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Analysis
by VulDB Data Team • 07/23/2018
The vulnerability identified as CVE-2016-1303 affects Cisco Small Business 500 series devices running firmware version 1.2.0.92 and earlier, specifically targeting the web graphical user interface component. This issue represents a denial of service vulnerability that can be exploited by remote attackers through the manipulation of HTTP requests, potentially disrupting network operations and service availability for legitimate users. The vulnerability was catalogued under Cisco Bug ID CSCul65330, indicating its classification within the company's internal tracking system for security issues.
The technical flaw resides in the web GUI's insufficient input validation and error handling mechanisms when processing HTTP requests. Attackers can craft specially designed HTTP requests that, when processed by the vulnerable device, trigger unexpected behavior leading to system instability and eventual service disruption. This weakness stems from inadequate sanitization of user-supplied input within the web interface component, allowing malicious payloads to interfere with normal device operations. The vulnerability demonstrates characteristics consistent with CWE-129, Input Validation and Type Confusion, where improper validation of input parameters leads to system instability. The web GUI component fails to properly validate the structure and content of incoming HTTP requests, creating an entry point for attackers to exploit the device's processing logic.
The operational impact of this vulnerability extends beyond simple service disruption, potentially affecting business continuity and network availability for small business environments that rely on these devices for their networking infrastructure. Organizations using affected Cisco Small Business 500 series devices may experience unauthorized denial of service conditions that could last until manual intervention or device reboot occurs. The remote exploitation capability means that attackers do not require physical access or network proximity to the device, making the vulnerability particularly concerning for environments where network security controls may be limited. This vulnerability aligns with ATT&CK technique T1499.004, "Endpoint Denial of Service," where adversaries target network infrastructure devices to disrupt service availability.
Mitigation strategies for CVE-2016-1303 should prioritize immediate firmware updates from Cisco to address the identified vulnerability, as the vendor has released patches specifically designed to correct the input validation flaws in the web GUI component. Network administrators should also implement access controls and firewall rules to limit HTTP access to the device to trusted networks only, reducing the attack surface for remote exploitation. Additionally, monitoring network traffic for suspicious HTTP request patterns and implementing intrusion detection systems can help identify potential exploitation attempts. The vulnerability underscores the importance of maintaining up-to-date firmware across all network infrastructure components, particularly in small business environments where security updates may be overlooked. Organizations should also consider segmenting critical network infrastructure and implementing network access controls to limit exposure of vulnerable devices to untrusted network segments.