CVE-2020-3295 in RV016
Summary
by MITRE
Multiple vulnerabilities in the web-based management interface of Cisco Small Business RV320 and RV325 Series Routers and Cisco Small Business RV016, RV042, and RV082 Routers could allow an authenticated, remote attacker with administrative privileges to execute arbitrary code on an affected device. The vulnerabilities are due to insufficient boundary restrictions on user-supplied input to scripts in the web-based management interface. An attacker with administrative privileges that are sufficient to log in to the web-based management interface could exploit each vulnerability by sending crafted requests that contain overly large values to an affected device, causing a stack overflow. A successful exploit could allow the attacker to cause the device to crash or allow the attacker to execute arbitrary code with root privileges on the underlying operating system.
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Analysis
by VulDB Data Team • 10/25/2020
The CVE-2020-3295 vulnerability affects Cisco Small Business routers including RV320 and RV325 series devices along with RV016, RV042, and RV082 models, representing a critical security flaw in their web-based management interfaces. This vulnerability stems from inadequate input validation mechanisms that fail to properly restrict user-supplied data entering the system through web scripts. The flaw exists within the boundary checking processes that should prevent malicious input from causing system instability or unauthorized code execution. Security researchers identified that these routers implement insufficient sanitization of parameters passed to internal scripts, creating potential attack vectors for authenticated remote exploitation.
The technical implementation of this vulnerability involves stack overflow conditions that occur when maliciously crafted requests containing excessively large parameter values are sent to the affected devices. When administrative users log into the web interface, they inadvertently expose themselves to attack vectors that can be exploited by adversaries who have already obtained administrative credentials. The vulnerability specifically targets the input handling mechanisms within the web management interface scripts, where buffer overflow conditions can be triggered by sending oversized data payloads that exceed the allocated stack space. This design flaw allows attackers to manipulate memory structures within the router's operating system, potentially leading to complete system compromise.
From an operational perspective, the impact of this vulnerability is severe as it enables authenticated remote code execution with root privileges on the underlying operating system. Attackers who have already gained administrative access to the device can leverage this vulnerability to escalate their privileges further, potentially gaining complete control over the router's functionality. The exploitation process requires only a single authenticated session, making it particularly dangerous for network environments where administrative credentials might be compromised through other means. The resulting system crashes or code execution capabilities provide attackers with persistent access to the network infrastructure, enabling potential data exfiltration, network reconnaissance, or further lateral movement attacks.
Organizations should implement immediate mitigations including applying Cisco's security patches and firmware updates that address the input validation flaws in the web management interface. Network segmentation strategies should be employed to limit the attack surface, ensuring that administrative access to these devices is restricted to authorized personnel only. Regular monitoring of device logs for suspicious activity and implementing network access controls can help detect potential exploitation attempts. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and maps to ATT&CK technique T1059 for command and scripting interpreter usage, as attackers may leverage the compromised devices for further network infiltration. Additionally, organizations should consider implementing network intrusion detection systems that can identify malformed requests targeting the web interface and establish strict access control policies for administrative interfaces.