CVE-2021-1191 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-2021-1191 affects Cisco Small Business routers including RV110W, RV130, RV130W, and RV215W models, representing a critical security flaw in their web-based management interfaces. This vulnerability stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied data before processing within the device's operating system. The flaw exists in the web interface components that handle HTTP requests from administrators, creating a pathway for malicious exploitation when legitimate administrative credentials are compromised. The affected devices operate on embedded operating systems that are particularly susceptible to code execution vulnerabilities when input validation is insufficient, making these routers attractive targets for attackers seeking persistent access to network infrastructure.
The technical implementation of this vulnerability manifests through improper handling of HTTP request parameters within the web management interface of these small business routers. When an authenticated administrator sends crafted HTTP requests containing malicious input, the system fails to validate or sanitize the data properly before processing it within the underlying operating system. This insufficient validation creates opportunities for attackers to inject malicious code that executes with root privileges, effectively providing complete system compromise. The vulnerability's classification aligns with CWE-20, which describes improper input validation as a fundamental weakness that allows attackers to manipulate system behavior through malformed input. The attack vector requires network access to the device and valid administrative credentials, making it a privilege escalation vulnerability rather than a purely remote exploit.
The operational impact of CVE-2021-1191 extends beyond simple code execution capabilities to include significant denial of service conditions that can disrupt network operations. When successfully exploited, the vulnerability allows attackers to cause unexpected device reboots, creating network downtime that can be particularly damaging for small business environments where continuous network availability is critical. The root-level code execution capability provides attackers with complete control over the device's functionality, enabling them to modify network configurations, redirect traffic, or establish persistent backdoors. This vulnerability directly impacts the CIA triad by compromising both confidentiality and availability, as attackers can access sensitive network information and disrupt service availability. The DoS component of this vulnerability can be particularly devastating in environments where these routers serve as critical network gateways.
Organizations affected by this vulnerability should implement immediate mitigations while awaiting potential vendor patches, as Cisco has not released software updates addressing these specific issues. The most effective immediate measure involves restricting administrative access to these devices through network segmentation and implementing strict access controls that limit who can reach the web management interfaces. Network monitoring should be enhanced to detect unusual traffic patterns or repeated authentication attempts that might indicate exploitation attempts. Security teams should consider disabling the web management interface entirely and relying on command-line interface access with strong authentication mechanisms. The vulnerability's exploitation requires valid administrative credentials, making credential management and access control policies crucial defensive measures. Organizations should also implement regular security audits to ensure that administrative accounts are properly secured and that unnecessary services are disabled to minimize attack surface. This vulnerability demonstrates the importance of implementing defense-in-depth strategies and maintaining awareness of vendor security advisories for network infrastructure devices.