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McAfee Security Bulletin: Protected resource access bypass vulnerability resolved in multiple McAfee endpoint products for Microsoft Windows (CVE-2016-3984)
Security Bulletins ID:   SB10151
Last Modified:  5/22/2017
Rated:


Summary

First Published: 02/25/2016
 
 Impact of Vulnerability:  Application Protections Bypass (CWE-592)
 CVE Numbers:  CVE-2016-3984
 Severity Rating:  Low
 Base / Overall CVSS v3 Scores:  3.1 / 2.9
 Base / Overall CVSS v2 Scores:  3.0 / 2.6
 Recommendations:  Install or update to the patch in the Remediation table
 Security Bulletin Replacement:  Related to SB10158: same discoverer, similar patch sequence, different vulnerability
 Affected Software:  Category 1:
 VirusScan Enterprise 8.8 (VSE)

 Category 2:
  McAfee Agent 5.x (MA)
  Data Exchange Layer (DXL)
  Host Intrusion Prevention Service (Host IPS) 8.0
  Data Loss Prevention Endpoint (DLPE)
  McAfee Device Control (MDC)
  Endpoint Security (ENS) 10.0
  McAfee Active Response (MAR)
 Location of Updated Software:  http://www.mcafee.com/us/downloads/downloads.aspx

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Article contents:

Description

Multiple McAfee endpoint products include a self-protection mechanism to determine which McAfee applications and associated actions, such as access to registry keys and files, can be trusted. The mechanism allows exclusions to prevent dead locks and infinite loops when multiple scanners are involved.  

Trusted applications can access settings and files protected by self-protection rules. For example, McAfee applications must be trusted before they are allowed to be uninstalled, preventing malicious attackers from uninstalling McAfee software without permission. After an attacker achieves local Windows administrative privileges, the self-protection mechanism can also be manipulated to control trust settings without possession of the management password.

The affected self-protection mechanism design is outdated and was being replaced. The replacement design was in development for several years and has now been included in the affected products.
 
When VSE is present on the device, processes that attempt to use this mechanism are scanned upon access. If the processes are not detected as malware, they could gain access to resources protected by McAfee products.

This update also addresses another issue that was very specific to the VSE product where closing the registry handles for the VSE process mcconsole.exe using Process Explorer (or similar tools) could be exploited to unlock the password protected VirusScan Console window. See SB10158 for additional details.

See the discoverer’s blog report at: https://packetstormsecurity.com/files/136089.
 
Products are grouped in two categories:
  • Category 1 Products:
    Ship the vulnerable technology and actively use the technology for their own self-protection or protection they offer to other McAfee products installed on the same device.
     
  • Category 2 Products:
    Ship the vulnerable technology, but have already transitioned to a new self-protection mechanism that does not rely on the vulnerable technology. They still require an update to fully disable the vulnerable technology.
This trusted access bypass vulnerability allows access to resources normally protected by the products. Someone with knowledge of this mechanism can use and exploit it. An attacker who has access to the computer with local admin rights could potentially use this vulnerability to bypass product self-protection and tamper with policies and product files.
 
The patches and hotfixes in the Remediation table remediate this issue for the following products:
  • Category 1:
    • VirusScan Enterprise (VSE)
     
  • Category 2:
    • Data Exchange Layer (DXL)
    • Host Intrusion Prevention Service (Host IPS)
    • McAfee Active Response (MAR)
    • McAfee Agent (MA)
    • McAfee Data Loss Prevention Endpoint (DLPe)
    • McAfee Device Control (MDC)
    • McAfee Endpoint Security (ENS)
CVE-2016-3984
The McAfee VirusScan Console (mcconsol.exe) in McAfee Active Response (MAR) before 1.1.0.161, Agent (MA) 5.x before 5.0.2 Hotfix 1110392 (5.0.2.333), Data Exchange Layer 2.x (DXL) before 2.0.1.140.1, Data Loss Prevention Endpoint (DLPe) 9.3 before Patch 6 and 9.4 before Patch 1 HF3, Device Control (MDC) 9.3 before Patch 6 and 9.4 before Patch 1 HF3, Endpoint Security (ENS) 10.x before 10.1, Host Intrusion Prevention Service (IPS) 8.0 before 8.0.0.3624, and VirusScan Enterprise (VSE) 8.8 before P7 (8.8.0.1528) on Windows allows local administrators to bypass intended self-protection rules and disable the antivirus engine by modifying registry keys.
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-3984

CWE-592
Application Protections Bypass
http://cwe.mitre.org/data/definitions/592.html
 
For a description of each product, see: http://www.mcafee.com/us/apps/products-az.aspx.

Remediation

Go to the Product Downloads site and download the applicable product patch/hotfix files:
 
Product Type Version File Name Release Date
Data Loss Prevention and Device Control 9.4 Hotfix 9.4 Patch 1 HF3

DLP ePO extension: (9.4.100.15)
DLPe client for Windows: (9.4.103.4)
McAfeeDLPEndPoint94P1HF3Licensed.zip January 12, 2016
Device Control 9.4 Hotfix 9.4 Patch 1 HF3

DLP ePO extension: (9.4.100.15)
DLPe client for Windows: (9.4.103.4)
McAfeeDeviceControl94P1HF3Licensed.zip January 12, 2016
Data Loss Prevention 9.3 Patch 6 Licensed Software Patch 9.3 Patch 6

DLP ePO extension: (9.3.600.5)
DLPe client: (9.3.600.32)
McAfeeDLPEndPoint93P6Licensed.zip January 14, 2016
Device Control 9.3 Patch 9.3 Patch 6

DLP ePO extension: (9.3.600.5)
DLPe client: (9.3.600.32)
McAfeeDeviceControl93P6Licensed.zip January 14, 2016
DXL Patch 2.0.1.140.1 DXL_2.0.1_Build_140_Package_1_(ENU-LICENSED-RELEASE-BRANCH).zip December 16, 2015
ENS for Mac Product  10.1   McAfee-Endpoint-Security-for-Mac-10.1.0-RTW-standalone-1997.dmg December 14, 2015
ENS For Windows Product 10.1 McAfee_Endpoint_Security_v10_1_0_649_61_stand_alone_client_install.zip December 16, 2015
Host IPS Patch 8.0.0.3624 (Patch 7) HIP80P7.zip February 25, 2016
MA Patch 5.0.3   May 9, 2016
MA Hotfix 5.0.2.333 MA502HF1110392WIN.zip February 25, 2016
MAR Hotfix 1.1.0.161  Mar_Client_Package_Win_1.1.0.161.zip    January 28, 2016
VSE Patch 8.8 P7 VSE880P7.zip February 25, 2016
VSE Hotfix 8.8 HF11233565 VSE880P7HF1123565.zip April 29, 2016

Download and Installation Instructions
See KB56057 for instructions on how to download McAfee products, documentation, security updates, patches, and hotfixes.  Review the Release Notes and the Installation Guide, which you can download from the Documentation tab, for instructions on how to install these updates.

Recommended Installation Sequence
The fix involved re-architecting the self-protection mechanisms in VSE, which functionally impacts multiple products. This architecture change creates an installation dependency between MA 5.0.3/MA 5.0.2.333 and VSE 8.8.0.1528. Please follow the recommended installation sequence to update to MA 5.0.3/MA 5.0.2.333 and VSE 8.8.0.1528 or later.

NOTE: This issue is resolved in both MA 5.0.2 Hotfix 1110392 and MA 5.0.3. Apart from this security fix, MA 5.0.3 contains additional fixes and functionality. For more details, see PD26438 - McAfee Agent 5.0.3 Release Notes.

Table A: Product Update Versions Sorted By Release Date

The following product versions are referenced in Table B below.
 
Product Version Release Build Package Date
VSE 8.8.0 Patch 5/6 Hotfix 1087536 8.8.0.1478 October 1, 2015
MA 5.0.2 Hotfix 1091027 5.0.2.188 November 18, 2015
VSE 8.8.0 Patch 7 8.8.0.1528 February 12, 2016
MA 5.0.2 Hotfix 1110392 5.0.2.333 February 25, 2016
VSE      8.8.0 Patch 6/7 Hotfix 1123565 8.8.0.1546 April 29, 2016

Table B: Install Sequence Chart

Refer to the following Installation Sequence Chart for guidance.
 
 
  Scenario 1 Scenario 2 Scenario 3 Scenario 4 Scenario 5
Starting Point for Products Installed VSE 8.8.0.1478:
No

MA 5.0.2.188:
No  
VSE 8.8.0.1478: 
Yes

MA 5.0.2.188:
Yes
VSE 8.8.0.1478: 
No

MA 5.0.2.188:
Yes
VSE:
Not Installed

MA: 4.x or 5.x:
Yes
VSE 8.8.0.1478:
Yes

MA 5.0.2.188:
No

MA 4.x:
Yes
Recommended Installation Sequence for Upgrade
  1. First Install: MA 5.0.2.188
  2. Then Install: VSE 8.8.0.1528
  3. Then Install: VSE Patch 6/7 Hotfix 1123565 8.8.0.1546
  4. Then Install MA 5.0.3/MA 5.0.2.333
  1. First Install: VSE 8.8.0.1528
  2. Then Install: VSE Patch 6/7 Hotfix 1123565 8.8.0.1546
  3. Then Install: MA 5.0.3/MA 5.0.2.333
Upgrade to MA 5.0.3/MA 5.0.2.333 Only Install:

VSE 8.8.0.1528

Then Install VSE Patch 6/7 Hotfix 1123565 8.8.0.1546

Leave MA at MA 4.x
Impact of Not Following Recommended Sequence No Impact.

The VSE 8.8.0.1528 installer checks to ensure that MA 5.0.2.188 or MA 5.0.3/MA 5.0.2.333 is installed first.  

If you attempt to install VSE 8.8.0.1478 after MA 5.0.3/MA 5.0.2.333, the install will fail. Instead, install VSE 8.8.0.1528 directly.
No Impact.

However, you  must upgrade to both MA 5.0.3/MA 5.0.2.333 and VSE 8.8.0.1528. 

If only VSE 8.8.0.1528 is installed and not MA 5.0.3/MA 5.0.2.333, product functionality will be impacted, as described in the following articles:
If no intent to install VSE, ensure MA is upgraded to MA 5.0.3/5.0.2.333.  

Otherwise, product functionality will be impacted as described in article: KB83895.
No Impact.
Remediation if Impact Occurs Install VSE 8.8.0.1528 and apply VSE Patch 6/7 Hotfix 1123565 8.8.0.1546 Ensure both MA 5.0.3/MA 5.0.2.333 and VSE 8.8.0.1546 are installed Install MA 5.0.3/MA 5.0.2.333 N/A
 

NOTE: For customers who want to upgrade from MA 4.x to MA 5.x, upgrade to MA 5.0.3/MA 5.0.2.333 or later.

Workaround

None. Install the described patches, hotfixes and version updates.

Mitigations

No vulnerability detection signatures are available.

Acknowledgements

McAfee credits Maurizio Agazzini (also known as inode) https://it.linkedin.com/in/maurizio-agazzini-b915243 from Mediaservice.net http://techblog.mediaservice.net/author/inode/ for reporting this flaw in VSE. He reported this issue in November 2014 and was gracious enough to allow us over a year to fix it correctly. It involved re-architecting the product's self-protection mechanisms, which functionally impacted multiple dependent products.

Maurizio reported this as one of two examples of the same vulnerability; however, upon further investigation it was determined that two different vulnerabilities were actually reported. This set of patches fixes Example #2. SB10158 fixes Example #1.

Frequently Asked Questions (FAQs)

How do I know whether my McAfee product is vulnerable or not?

For Endpoint products:
Use the following instructions for endpoint or client-based products:
  1. Right-click on the McAfee tray shield icon on the Windows task bar.
  2. Select Open Console.
  3. In the console, select Action Menu.
  4. In the Action Menu, select Product Details. The product version is displayed.
For ePO:
Check the version and build of ePO that is installed. For information on how to check the version, see KB52634.

For Appliances:
Use the following instructions for Appliance based products:
  1. Open the Administrator's User Interface (UI).
  2. Click the About link. The product version is displayed.
For DLPE ePO Extension:
Use the following instructions:
  1. Log on to ePO server.
  2. Click Menu, Data Protection, DLP Policy.
  3. Inside the DLP console click the Help menu item, About. The product version is displayed.
What is CVSS?
CVSS, or Common Vulnerability Scoring System, is the result of the National Infrastructure Advisory Council’s effort to standardize a system of assessing the criticality of a vulnerability. This system offers an unbiased criticality score between 0 and 10 that customers can use to judge how critical a vulnerability is and plan accordingly. For more information, please visit the CVSS website at: http://www.first.org/cvss/.

When calculating CVSS v2 scores, McAfee has adopted a philosophy that fosters consistency and repeatability. Our guiding principle for CVSS scoring is to score the exploit under consideration by itself. We consider only the immediate and direct impact of the exploit under consideration. We do not factor into a score any potential follow-on exploits that might be made possible by successful exploitation of the issue being scored.

CVSS v3 scoring is in final review as of December 2015. CVSS v2 will be replaced with CVSS v3 when v3 is fully approved. Security bulletins will have scores for both versions for at least 6 months after v3 is fully approved.
https://www.first.org/cvss/v3/development
https://www.first.org/cvss/calculator/3.0
 
What are the CVSS scoring metrics that have been used?
 
CVE-2016-3984: Multiple McAfee endpoint products for Microsoft Windows fix a protected resource access bypass vulnerability
 
CVSS v3 Scoring:
 
 Base Score 3.1
 Attack Vector (AV) Local (L)
 Attack Complexity (AC) Low (L)
 Privileges Required (PR) High (H)
 User Interaction (UI) Required (R)
 Scope (S) Unchanged (U)
Confidentiality (C) None (N)
Integrity (I) Low (L)
Availability (A) Low (L)
 Temporal Score (Overall) 2.9
 Exploitability (E) Functional (F)
 Remediation Level (RL) Temporary Fix (T)
 Report Confidence (RC) Confirmed (C)

NOTE: The below CVSS version 3.0 vector was used to generate this score.
https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:L/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:L/E:F/RL:T/RC:C

CVSS v2.0 Scoring:
 
 Base Score 3.0
 Related exploit range (AccessVector) Local (L)
 Attack complexity (AccessComplexity) Medium (M)
 Level of authentication needed (Authentication) Single (S)
 Confidentiality impact None (N)
 Integrity impact Partial (P)
 Availability impact Partial (P)
 Temporal Score (Overall) 2.6
 Availability of exploit (Exploitability) Functional Exploit Exists (F)
 Type of fix available (RemediationLevel) Temporary Fix (T)
 Level of verification that vulnerability exists (ReportConfidence) Confirmed (C)

NOTE: The below CVSS version 2.0 vector was used to generate this score.
https://nvd.nist.gov/cvss.cfm?calculator&version=2&vector=(AV:L/AC:M/Au:S/C:N/I:P/A:P/E:F/RL:T/RC:C)

Where can I find a list of all security bulletins or how do I report a product vulnerability?
To find a list of all security bulletins, or if you have information about a security issue or vulnerability with a McAfee product, please visit our product security website at: http://www.mcafee.com/us/threat-center/product-security-bulletins.aspx.

Resources

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Disclaimer

The information provided in this security bulletin is provided as is without warranty of any kind. McAfee disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall McAfee or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits, or special damages, even if McAfee or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.
 
Any future product release dates mentioned in this security bulletin are intended to outline our general product direction and they should not be relied on in making a purchasing decision. The product release dates are for information purposes only, and may not be incorporated into any contract. The product release dates are not a commitment, promise, or legal obligation to deliver any material, code, or functionality. The development, release, and timing of any features or functionality described for our products remains at our sole discretion and may be changed or cancelled at any time.

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