CVE-2021-1339 in RV016
Summary
by MITRE • 02/05/2021
Multiple vulnerabilities in the web-based management interface of Cisco Small Business RV016, RV042, RV042G, RV082, RV320, and RV325 Routers could allow an authenticated, remote attacker to execute arbitrary code or cause an affected device to restart unexpectedly. These 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.
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Analysis
by VulDB Data Team • 02/24/2021
The vulnerability CVE-2021-1339 represents a critical security flaw affecting Cisco Small Business routers including models RV016 RV042 RV042G RV082 RV320 and RV325. This vulnerability resides within the web-based management interface of these devices and stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied data. The flaw allows authenticated remote attackers to exploit the system through specially crafted HTTP requests that bypass normal security controls. This issue directly maps to CWE-20 which defines "Improper Input Validation" as a fundamental weakness that enables various attack vectors including code execution and denial of service conditions. The vulnerability demonstrates a classic privilege escalation scenario where legitimate administrative credentials provide attackers with sufficient access to manipulate the underlying operating system through the web interface.
The technical exploitation of this vulnerability occurs through the manipulation of HTTP request parameters that are not properly validated by the router's web management interface. When an attacker submits maliciously crafted requests containing malformed input, the system fails to adequately validate or sanitize these inputs before processing them within the router's operating system. This improper validation creates a pathway for arbitrary code execution with root privileges, effectively allowing attackers to gain complete control over the affected device. The attack requires only valid administrator credentials which are often obtained through social engineering phishing campaigns or credential reuse attacks. The exploitation process leverages the web interface's trust in authenticated users while failing to implement proper input sanitization for all request parameters, creating a dangerous combination of authentication bypass and input validation failure that can result in full system compromise.
From an operational impact perspective, the vulnerability presents significant risks to network infrastructure security as it allows attackers to achieve persistent control over critical network devices. The ability to execute arbitrary code as root user provides attackers with complete system access including the capability to modify network configurations, install backdoors, or establish persistent access points. Additionally the vulnerability can cause unexpected device restarts which creates denial of service conditions that can disrupt network operations and potentially cause cascading failures in network infrastructure. The affected devices typically serve as network gateways and security boundaries, making their compromise particularly dangerous for organizations relying on these devices for network segmentation and access control. The vulnerability also impacts the principle of least privilege as legitimate administrative access becomes a potential attack vector for privilege escalation.
Organizations should implement immediate mitigations including restricting administrative access to these devices through network segmentation and implementing strong access controls. The primary defense mechanism involves ensuring that administrator credentials are protected through multi-factor authentication and regular credential rotation. Network administrators should also consider disabling the web-based management interface when possible and using SSH or other secure management protocols instead. The vulnerability highlights the importance of implementing proper input validation controls as recommended by the OWASP Top 10 security framework and aligns with ATT&CK technique T1059.007 for command and scripting interpreter. Regular security updates and patch management procedures should be enforced to address such vulnerabilities before they can be exploited. Organizations should also implement network monitoring to detect unusual traffic patterns that might indicate exploitation attempts and establish incident response procedures for handling potential compromise scenarios. The vulnerability underscores the necessity of applying defense-in-depth strategies that combine multiple security controls to protect critical network infrastructure components from both external and internal threats.