CVE-2021-1321 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 identified as CVE-2021-1321 represents a critical security flaw affecting multiple Cisco Small Business routers including RV016, RV042, RV042G, RV082, RV320, and RV325 models. This vulnerability stems from insufficient input validation mechanisms within the web-based management interface, creating a pathway for authenticated remote attackers to compromise the affected devices. The flaw resides in the improper handling of user-supplied input, which allows maliciously crafted HTTP requests to be processed without adequate sanitization or validation checks. The affected devices operate on embedded operating systems that are particularly susceptible to such input manipulation attacks due to the limited security controls typically present in consumer-grade networking equipment.
The technical exploitation of this vulnerability requires an attacker to possess valid administrator credentials, establishing a baseline authentication requirement that limits the attack surface but does not eliminate the risk entirely. Once authenticated, the attacker can craft specific HTTP requests that bypass input validation controls, leading to arbitrary code execution with root privileges on the underlying operating system. This privilege escalation capability enables complete system compromise, allowing attackers to modify device configurations, access network traffic, install malicious software, or establish persistent backdoors. The vulnerability also permits denial of service conditions through device reloads, which can disrupt network connectivity and availability for legitimate users. The root cause of this issue aligns with CWE-20, which describes improper input validation, and demonstrates how weak input sanitization can lead to severe remote code execution vulnerabilities.
The operational impact of CVE-2021-1321 extends beyond simple privilege escalation to encompass comprehensive network compromise and service disruption. Organizations relying on these routers for network security may experience unauthorized access to their network infrastructure, potentially leading to data breaches, man-in-the-middle attacks, or lateral movement within the network. The DoS capability creates additional operational concerns as attackers can cause unexpected device reboots, leading to network outages and service interruptions that may go unnoticed until significant damage has occurred. The vulnerability affects both the network security posture and operational continuity of affected organizations, particularly those with limited cybersecurity resources who may not regularly update their network infrastructure. These routers are commonly deployed in small business environments where security monitoring may be minimal, making the exploitation of such vulnerabilities particularly dangerous.
Mitigation strategies for CVE-2021-1321 should prioritize immediate patching of affected devices through official Cisco security advisories and firmware updates. Organizations must ensure that all affected routers receive the latest security patches that address the input validation flaws in their web interfaces. Network segmentation and access control measures should be implemented to limit the scope of potential exploitation, while monitoring systems should be deployed to detect unusual authentication patterns or network behavior that may indicate compromise. The principle of least privilege should be enforced by restricting administrative access to only necessary personnel and implementing multi-factor authentication where possible. Security teams should conduct comprehensive vulnerability assessments to identify all affected devices within their networks and establish regular update procedures to maintain security postures against similar vulnerabilities. The ATT&CK framework categorizes this vulnerability under T1059 for command and scripting interpreter and T1498 for network denial of service, highlighting the dual nature of the threat as both an execution vector and a potential disruption mechanism. Regular security audits and network monitoring are essential to detect exploitation attempts and maintain defense-in-depth strategies against such sophisticated attacks.