CVE-2021-1340 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 CVE-2021-1340 vulnerability represents a critical security flaw affecting multiple Cisco Small Business routers including RV016, RV042, RV042G, RV082, RV320, and RV325 models. This vulnerability resides within the web-based management interface of these devices, creating a significant attack surface that could be exploited by authenticated remote adversaries. The flaw stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied data before processing, allowing malicious actors to manipulate the system through carefully crafted HTTP requests. This type of vulnerability is particularly dangerous as it operates at the application layer where user interactions are processed, making it a prime target for exploitation in network infrastructure devices.
The technical implementation of this vulnerability demonstrates a classic case of input validation failure that aligns with CWE-20, which describes improper input validation as a fundamental weakness in software security. When an authenticated administrator accesses the web interface, the system processes HTTP requests without sufficient sanitization of parameters, allowing attackers to inject malicious payloads that can be executed with root privileges. The exploitation process requires valid administrative credentials, which means attackers must first compromise these credentials through social engineering, credential stuffing, or other authentication bypass techniques before they can leverage this vulnerability. This authentication requirement does not mitigate the risk significantly as it represents a privilege escalation issue rather than an authentication bypass, making the attack surface broader than initially apparent.
The operational impact of CVE-2021-1340 extends beyond simple code execution capabilities to include potential denial of service conditions that could severely disrupt network operations. An attacker who successfully exploits this vulnerability can execute arbitrary code as the root user on the underlying operating system, effectively gaining complete control over the device and potentially the network segment it manages. This root-level access enables attackers to modify device configurations, install backdoors, redirect traffic, or exfiltrate sensitive data from the network. The device restart functionality represents a denial of service vector that could be used to maintain persistent access or simply disrupt network connectivity, depending on the attacker's objectives. The vulnerability affects multiple router models in the Cisco Small Business line, indicating a widespread issue that could impact numerous small and medium business networks.
From an attack framework perspective, this vulnerability maps to several ATT&CK techniques including T1059 for command and scripting interpreter, T1068 for exploit for privilege escalation, and T1499 for endpoint denial of service. The attack chain typically begins with credential compromise followed by exploitation of the web interface vulnerability, which aligns with the MITRE ATT&CK framework's methodology for understanding adversary behavior patterns. Network administrators should recognize that these devices often serve as critical network gateways, making their compromise particularly damaging to overall network security posture. The vulnerability's impact is amplified by the fact that these routers are commonly deployed in small business environments where security monitoring and incident response capabilities may be limited, creating an environment where exploitation could go unnoticed for extended periods.
Mitigation strategies for CVE-2021-1340 should focus on immediate patching of affected devices through Cisco's security advisories, which typically provide firmware updates addressing the input validation issues. Network segmentation and access control measures should be implemented to limit exposure of these devices to untrusted networks, while monitoring systems should be deployed to detect unusual HTTP traffic patterns that might indicate exploitation attempts. Administrative credentials should be protected through strong authentication mechanisms including multi-factor authentication, and regular credential rotation should be enforced. Network administrators should also consider implementing network access control lists to restrict access to the web management interfaces to only trusted administrative workstations. Additionally, regular security assessments and vulnerability scanning should be conducted to identify other potential weaknesses in the network infrastructure that could be leveraged in conjunction with this vulnerability.