CVE-2021-1166 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.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 02/13/2021
The vulnerability identified as CVE-2021-1166 affects Cisco Small Business routers including models RV110W, RV130, RV130W, and RV215W, 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, creating a pathway for malicious exploitation. The vulnerability classifies under CWE-20, which specifically addresses improper input validation, making it a fundamental weakness in the application's security architecture. These routers operate with embedded operating systems that are particularly susceptible to code execution attacks when input validation controls are bypassed.
The technical exploitation of this vulnerability requires an attacker to possess valid administrator credentials, establishing a privileged access requirement that significantly impacts the attack surface. However, once authenticated, the attacker can craft malicious HTTP requests that exploit the input validation gaps in the web interface. The attack vectors leverage the web-based management interface's failure to properly validate and sanitize data submitted through HTTP parameters, which can lead to command injection or arbitrary code execution at the root level of the device's operating system. This represents a severe privilege escalation vulnerability that allows attackers to gain full control over the affected devices.
The operational impact of CVE-2021-1166 extends beyond simple code execution to include potential denial of service conditions through device reboots. When exploited successfully, attackers can cause unexpected device reloads that disrupt network connectivity and service availability. The vulnerability's potential for remote code execution as root user creates a complete compromise scenario where attackers can modify router configurations, establish backdoors, or exfiltrate network data. This risk is particularly concerning for small business environments where these devices often serve as primary network gateways and may lack robust network monitoring or intrusion detection capabilities.
The exploitation of these vulnerabilities aligns with ATT&CK technique T1059, which covers command and scripting interpreter, as the attackers can execute arbitrary commands on the compromised devices. Organizations using these affected router models face significant risk without mitigation, as Cisco has not provided software updates to address these specific issues. The vulnerability's persistence across multiple router models indicates a systemic flaw in Cisco's development practices for these devices, particularly concerning the web interface implementation and input validation mechanisms. Network defenders should consider implementing network segmentation, monitoring for unusual HTTP traffic patterns, and restricting administrative access to these devices through network access control lists to reduce the attack surface and potential impact of exploitation attempts.