CVE-2020-15415 Scanner

DrayTek Vigor is a line of routers and network devices commonly used by small to medium-sized businesses and home offices for reliable internet connectivity and network management. Developed by DrayTek, these devices provide features like VPN capabilities, firewall settings, and wireless access points, facilitating robust network solutions. Businesses leverage DrayTek Vigor products to manage multiple network connections, ensuring efficient load balancing and failover support. The devices are valued for their ease of configuration, making them suitable for less technical users while still offering advanced options for network administrators. DrayTek Vigor is known for its quality performance and strong customer support, which has bolstered its adoption in various networking environments. They are often deployed in industries such as education, healthcare, and retail, where stable network infrastructure is crucial.

The command injection vulnerability in DrayTek Vigor allows remote attackers to execute arbitrary commands on the device. It is found in the cvmcfgupload functionality, specifically at the /cgi-bin/mainfunction.cgi/cvmcfgupload endpoint. This flaw can be exploited without authentication, making it particularly concerning for exposed devices. Attackers can leverage specially crafted requests to gain unauthorized control over the device, potentially compromising the entire network. The critical nature of the vulnerability is due to its potential impact on confidentiality, integrity, and availability of the network services. Identification and patching of this vulnerability are crucial to maintaining network security in environments using these devices.

This vulnerability involves a specific endpoint in the DrayTek Vigor device's web interface that does not sanitize user input properly. The endpoint /cgi-bin/mainfunction.cgi/cvmcfgupload is susceptible to command injection through malformed requests permitting execution of arbitrary commands. The crafted request exploits a multipart/form-data request to sneak command execution through filename parameters. Successful exploitation could yield command execution capabilities, allowing attackers unauthorized access to the system. The presence of status code 200 and particular response patterns like user identification in the output verifies the vulnerability. Detection requires assessing specific header content, indicating a successful breach and command execution.

If exploited, this vulnerability could enable attackers to execute arbitrary commands on the affected device. Such command injection could lead to unauthorized access to sensitive data and allow further infiltration of connected systems. Attacks could disrupt the network services, create backdoors for persistent access, or exfiltrate data from the organization’s network. Compromised devices might become part of a botnet, used for launching widespread attacks such as DDoS. The criticality of the potential impact highlights the necessity for urgent remediation to prevent severe network compromise and data breaches.

REFERENCES

• https://github.com/CLP-team/Vigor-Commond-Injection
• https://nvd.nist.gov/vuln/detail/CVE-2020-15415