CVE-2021-1173 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 CVE-2021-1173 vulnerability affects Cisco Small Business routers including RV110W, RV130, RV130W, and RV215W models, representing a critical security flaw in their web-based management interfaces. These devices operate with embedded operating systems that handle administrative functions through HTTP-based web portals, making them susceptible to injection attacks when user input is not properly validated. The vulnerability stems from insufficient sanitization of HTTP request parameters, allowing maliciously crafted inputs to bypass security controls and potentially escalate privileges within the device's operating system. The affected devices typically run on Linux-based systems with web servers that process configuration requests through CGI scripts and web interface components that handle user authentication and administrative commands.
The technical exploitation of these vulnerabilities occurs through crafted HTTP requests that manipulate input fields within the web management interface, leveraging improper input validation mechanisms that fail to properly filter or sanitize user-supplied data. Attackers can exploit this weakness by crafting HTTP requests containing malicious payloads that are processed by the device's web server, potentially leading to command injection attacks that execute with root privileges. The vulnerability specifically targets the web interface's handling of user inputs through form fields, URL parameters, or POST data, where insufficient validation allows attackers to inject commands that are executed on the underlying operating system. This type of flaw aligns with CWE-79, which describes cross-site scripting vulnerabilities, and CWE-89, which covers SQL injection attacks, though the specific implementation involves command injection rather than database exploitation.
The operational impact of CVE-2021-1173 extends beyond simple privilege escalation to include potential system compromise and denial of service conditions, making it particularly dangerous for network infrastructure devices. Successful exploitation could allow attackers to execute arbitrary code as the root user, providing complete control over the router's functionality and potentially enabling lateral movement within the network. The vulnerability's ability to cause unexpected device restarts creates additional operational concerns as it can be used for denial of service attacks against critical network infrastructure. Network administrators face significant challenges since these devices are often deployed in small business environments where security monitoring may be limited, and the lack of official software updates from Cisco leaves affected organizations vulnerable to exploitation. The attack vector requires valid administrator credentials, meaning that the vulnerability is typically exploited by authenticated attackers who have already gained access to legitimate administrative accounts.
Organizations affected by CVE-2021-1173 should implement immediate mitigations including network segmentation to isolate these devices from critical network segments, implementing strong access controls and credential management practices, and monitoring for suspicious administrative activities. The vulnerability's classification under the MITRE ATT&CK framework would fall under T1059 for command and scripting interpreter, specifically focusing on the execution of code through legitimate system tools. Given that Cisco has not released software updates addressing this vulnerability, network administrators should consider implementing network-based intrusion detection systems to monitor for exploitation attempts and establish emergency response procedures. The lack of vendor patches makes this vulnerability particularly concerning as it leaves devices permanently exposed to exploitation, requiring organizations to either replace affected hardware or implement network-level controls to prevent unauthorized access to the web management interfaces. Organizations should also consider implementing multi-factor authentication for administrative access and regularly reviewing access logs for suspicious activities that might indicate exploitation attempts.