CVE-2021-1167 in Small Business
Summary
by MITRE • 01/14/2021
Multiple vulnerabilities in the web-based management interface of Cisco Small Business RV110W, RV130, RV130W, and RV215W Routers could allow an authenticated, remote attacker to execute arbitrary code or cause an affected device to restart unexpectedly. The vulnerabilities are due to improper validation of user-supplied input in the web-based management interface. An attacker could exploit these vulnerabilities by sending crafted HTTP requests to an affected device. A successful exploit could allow the attacker to execute arbitrary code as the root user on the underlying operating system or cause the device to reload, resulting in a denial of service (DoS) condition. To exploit these vulnerabilities, an attacker would need to have valid administrator credentials on the affected device. Cisco has not released software updates that address these vulnerabilities.
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Analysis
by VulDB Data Team • 02/13/2021
The vulnerability identified as CVE-2021-1167 affects Cisco Small Business routers including the RV110W, RV130, RV130W, and RV215W models, representing a critical security flaw in their web-based management interfaces. This issue stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied data before processing within the device's operating system. The vulnerability architecture aligns with CWE-20, which categorizes improper input validation as a fundamental weakness in software design that enables various attack vectors including code execution and denial of service conditions. The affected devices operate on embedded operating systems that are particularly susceptible to such flaws due to limited resources and constrained security controls compared to enterprise-grade systems.
The technical exploitation of CVE-2021-1167 requires an authenticated attacker with valid administrator credentials, which significantly reduces the attack surface but does not eliminate the risk entirely. Attackers can craft malicious HTTP requests that bypass input validation checks, allowing them to inject and execute arbitrary code with root privileges on the underlying operating system. This privilege escalation capability directly maps to ATT&CK technique T1068, which describes local privilege escalation through exploitation of software vulnerabilities. The vulnerability's impact extends beyond code execution to include denial of service conditions through device reloads, effectively creating a persistent disruption vector that can be leveraged for ongoing service degradation attacks.
The operational implications of this vulnerability are severe for organizations relying on these small business routers for network infrastructure. Network administrators face the challenge of maintaining secure access controls while ensuring that legitimate users can manage their network devices effectively. The lack of available software updates from Cisco creates a persistent exposure window that requires immediate operational response measures. Organizations must implement network segmentation strategies to limit access to these devices, enforce strict credential management policies, and consider alternative network monitoring approaches to detect anomalous behavior indicative of exploitation attempts. The vulnerability's presence in multiple router models within the same product line suggests a systemic design flaw that may affect other devices in the Cisco Small Business portfolio, necessitating broader security assessments.
Mitigation strategies for CVE-2021-1167 should focus on layered defensive approaches that address both the immediate threat and potential future exploitation attempts. Network access controls should be implemented to restrict administrative access to these devices to only authorized personnel and systems, utilizing role-based access controls and multi-factor authentication mechanisms. Organizations should establish monitoring protocols that detect unusual HTTP request patterns or unauthorized administrative access attempts, leveraging security information and event management systems to correlate relevant network traffic. Given the absence of vendor patches, operational security teams must consider temporary network isolation of affected devices or implementing network access control lists that restrict communication to essential services only. The vulnerability serves as a reminder of the importance of maintaining current security patches and the risks associated with legacy device support in enterprise environments, particularly for critical infrastructure components that lack vendor support for known vulnerabilities.