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Security controls bypass or absence - Antivirus

Need​

Implementation of robust antivirus and data loss prevention (DLP) solutions

Context​

  • Usage of Java for building cross-platform applications
  • Usage of javax.servlet for building Java web applications with Servlet technology
  • Usage of java.io for input and output operations in Java

Description​

Non compliant code​

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;

public class AntivirusDisableServlet extends HttpServlet {

    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String antivirusStatus = request.getParameter("antivirusStatus");
        if (antivirusStatus.equals("disable")) {
            disableAntivirus();
        }
    }

    private void disableAntivirus() {
        try {
            Runtime.getRuntime().exec("cmd /c start antivirus_disable.bat");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

The above code represents a servlet in a Java web application that accepts HTTP POST requests. It checks for a parameter called antivirusStatus in the request. If the value of this parameter is "disable", it calls the disableAntivirus() method.

The disableAntivirus() method runs a command to execute a batch file named antivirus_disable.bat. This batch file is assumed to contain commands that disable the antivirus software on the server where this application is running.

The vulnerability here is that the application does not perform any authentication or authorization checks before accepting the request to disable the antivirus. An attacker can send a crafted HTTP POST request with antivirusStatus parameter set to "disable" and the application will disable its antivirus protection.

This is a serious security vulnerability as it allows an attacker to disable the antivirus protection and then execute malicious code or perform other types of attacks on the server. The application should always perform proper authentication and authorization checks before accepting any requests that can potentially modify its security settings.

Steps​

  • Implement proper input validation and sanitization to prevent unauthorized modification of the 'antivirusStatus' parameter.
  • Implement access controls to ensure that only authorized users can disable the antivirus.
  • Avoid executing external commands directly and instead use secure APIs or libraries to interact with antivirus software.
  • Regularly update and patch the antivirus software to ensure it has the latest security controls.
  • Implement additional security controls such as intrusion detection systems (IDS) and data loss prevention (DLP) to complement the antivirus protection.

Compliant code​

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.security.Principal;

public class AntivirusDisableServlet extends HttpServlet {

    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        Principal userPrincipal = request.getUserPrincipal();
        if (userPrincipal == null || !userPrincipal.getName().equals("authorizedUser")) {
            response.sendError(HttpServletResponse.SC_FORBIDDEN, "Unauthorized access");
            return;
        }

        String antivirusStatus = request.getParameter("antivirusStatus");
        if (antivirusStatus != null && antivirusStatus.equals("disable")) {
            disableAntivirus();
        }
    }

    private void disableAntivirus() {
        // Use secure APIs or libraries to interact with antivirus software
        // This is just a placeholder, replace with actual implementation
        AntivirusAPI antivirusAPI = new AntivirusAPI();
        try {
            antivirusAPI.disable();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

The updated code includes several security enhancements to address the vulnerability:

  1. Access Control: The doPost method now checks if the user is authenticated and authorized before proceeding. If the user is not authenticated or is not the authorized user, the method returns an HTTP 403 (Forbidden) error.

  2. Input Validation: The doPost method now checks if the 'antivirusStatus' parameter is not null before comparing it to the string "disable". This prevents a NullPointerException which could occur if the parameter is not provided in the request.

  3. Secure Interaction with Antivirus Software: Instead of executing an external command to disable the antivirus, which is a security risk, the disableAntivirus method now uses a hypothetical secure API or library to interact with the antivirus software. This is represented by the AntivirusAPI class, which is a placeholder for the actual implementation.

Remember to regularly update and patch the antivirus software to ensure it has the latest security controls. Also, consider implementing additional security controls such as intrusion detection systems (IDS) and data loss prevention (DLP) to complement the antivirus protection.

References​

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