Sonicwall SSLVPN Remote Code Execution (RCE) Scanner

Sonicwall SSLVPN is widely used by businesses and organizations to provide secure remote access to network resources. It allows employees to connect to company networks from remote locations, ensuring network and data security. Sonicwall SSLVPN is known for its robust security features and ease of deployment, making it a preferred choice for ensuring secure remote access. The software supports a range of applications and allows for secure communication across various devices. It helps in streamlining network management with its centralized control features. Administrators choose Sonicwall SSLVPN for its comprehensive security capabilities and ease of use.

The Remote Code Execution (RCE) vulnerability detected in Sonicwall SSLVPN is a critical security flaw. It allows attackers to execute arbitrary code on the affected system without authentication. This vulnerability is exploited using the ShellShock bug, which affects systems utilizing certain versions of Bash. ShellShock allows an attacker to execute shell commands with elevated privileges. The flaw is particularly dangerous as it requires minimal effort to exploit and can lead to complete system compromise. This vulnerability poses a significant risk to systems using vulnerable Sonicwall SSLVPN installations.

Technical details about the vulnerability reveal that it is triggered through a malformed 'User-Agent' header exploiting the ShellShock vulnerability. The vulnerable endpoint is accessed via the CGI script located at '/cgi-bin/jarrewrite.sh'. A specially crafted HTTP request is used to inject the payload that leads to the command execution. The malicious input '() { :; }; echo ; /bin/bash -c 'cat /etc/passwd'' demonstrates exploitation by attempting to read the system's password file. Successful exploitation results in sensitive information disclosure and potential system takeover. This type of vulnerability is serious due to its impact and ease of exploitation.

Exploitation of this vulnerability can have severe consequences, including unauthorized access to sensitive information. Attackers can execute arbitrary commands, potentially installing malware or creating backdoors for persistent access. The vulnerability might also lead to data breaches, tampering of critical data, and disruption of services. System integrity can be compromised, affecting business operations and leading to significant financial and reputational damage. The vulnerability underscores the importance of timely patching and deployment of security updates to prevent exploitation.

REFERENCES

• https://twitter.com/chybeta/status/1353974652540882944
• https://darrenmartyn.ie/2021/01/24/visualdoor-sonicwall-ssl-vpn-exploit/