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McAfee Security Bulletin - Drive Encryption update fixes authentication bypass vulnerability when Trusted Platform Module autoboot is enabled (CVE-2018-6686)
Security Bulletins ID:   SB10242
Last Modified:  7/9/2018


First Published: July 10, 2018
 Impact of Vulnerability: Authentication bypass (CWE-592)
 CVE ID: CVE-2018-6686
 Severity Rating: High
 CVSS v3 Base/Temporal Scores: 7.0 / 6.3
 Recommendations: Install or update to Drive Encryption 7.1.3 HF1241165, or Drive Encryption 7.2.6
 Security Bulletin Replacement: None
 Affected Software: Drive Encryption 7.1.0 and later
 Location of updated software: http://www.mcafee.com/us/downloads/downloads.aspx
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Article contents: Vulnerability Description
The issue is related to the Trusted Platform Module (TPM) autoboot feature first introduced in Drive Encryption 7.1.0, which could allow a third party (who has physical access), to boot the system and gain unauthorized access.

Authentication Bypass vulnerability in TPM autoboot in McAfee Drive Encryption (DE) 7.1.0 and above, allows physically proximate attackers to bypass local security protection, via a specific set of circumstances.
NOTE: The following link was not yet populated with CVE details at the time of publication of this Security Bulletin.
To remediate this issue, update the clients to Drive Encryption 7.1.3 HF1241165, or Drive Encryption 7.2.6.

Go to the Product Downloads site, and download the applicable product patch or hotfix file:
Product Versions Type File Name Release Date
Drive Encryption 7.1.x  Hotfix Release to World (RTW), version 7.1.3 HF1241165 July 10, 2018
Drive Encryption 7.2.0 – 7.2.5 Update RTW, version 7.2.6 July 10, 2018
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.
Product Specific Notes
For additional information about TPM autoboot, refer to the FunctionalityTPM (Autoboot) section of the Drive Encryption 7.x FAQs Knowledge Base article KB79784.
To disable TPM autoboot from ePO:
  1. Log on to the ePO console.
  2. Navigate to Policy Catalog.
  3. Edit the Product Policy.
  4. Click the Log on tab.
  5. Ensure that Enable automatic booting is not enabled (deselected).
  6. Ensure that Use of TPM for automatic booting is set to Never.
  7. Click Save.
  8. Repeat steps 3-7 for all Product Policies.
When the McAfee Agent agent-to-server communication interval next enforces the policies, TPM autoboot is disabled.

NOTE: When TPM autoboot is disabled, end users are presented with the Drive Encryption preboot (PBA) environment on the next reboot. When TPM autoboot is enabled, there is no synchronization of Windows passwords to preboot passwords. So, the preboot passwords of users might not match their current Windows password, when TPM autoboot is disabled and user authentication is enabled.

McAfee strongly recommends that you install the available hotfix or update specified in the Remediation table.
Frequently Asked Questions (FAQs)
How do I know if 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 taskbar.
  2. Select Open Console.
  3. In the console, select Action Menu.
  4. In the Action Menu, select Product Details. 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, visit the CVSS website at: http://www.first.org/cvss/.
When calculating CVSS 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 the successful exploitation of the issue being scored.
What are the CVSS scoring metrics?

CVE-2018-6686: Authentication bypass vulnerability in TPM autoboot
Base Score 7.0
Attack Vector (AV) Physical (P)
Attack Complexity (AC) Low (L)
Privileges Required (PR) None (N)
User Interaction (UI) Required (R)
Scope (S) Changed (C)
Confidentiality (C) High (H)
Integrity (I) High (H)
Availability (A) None (N)
Temporal Score (Overall) 6.3
Exploitability (E) Proof-of-Concept (P)
Remediation Level (RL) Official Fix (O)
Report Confidence (RC) Confirmed (C)
NOTE: The below CVSS version 3.0 vector was used to generate this score.

Where can I find a list of all Security Bulletins?
All Security Bulletins are published on our external PSIRT website at http://www.mcafee.com/us/threat-center/product-security-bulletins.aspx > Security Bulletins. Security Bulletins are retired (removed) once a product is both End of Sale and End of Support (End of Life).
How do I report a product vulnerability to McAfee?
If you have information about a security issue or vulnerability with a McAfee product, visit the McAfee PSIRT website for instructions at http://www.mcafee.com/us/threat-center/product-security-bulletins.aspx > Report a Security Vulnerability.
How does McAfee respond to this and any other reported security flaws?
McAfee's key priority is the security of our customers. If a vulnerability is found within any of McAfee's software or services, we work closely with the relevant security software development team to ensure the rapid and effective development of a fix and communication plan.
McAfee only publishes Security Bulletins if they include something actionable such as a workaround, mitigation, version update, patch, or hotfix; otherwise we would simply be informing the hacker community that our products are a target, putting our customers at greater risk. For products that are updated automatically, a non-actionable Security Bulletin might be published to acknowledge the discoverer.
View our PSIRT policy on the McAfee PSIRT website at http://www.mcafee.com/us/threat-center/product-security-bulletins.aspx > About PSIRT.

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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 canceled at any time.

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