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McAfee Security Bulletin - McAfee Agent update fixes a Use After Free vulnerability in the remote logging feature (CVE-2018-6703)
Security Bulletins ID:   SB10258
Last Modified:  3/21/2019


First Published: December 11, 2018
 Impact of Vulnerability: Use After Free (CWE-416)
 CVE ID: CVE-2018-6703
 Severity Rating: Critical
 CVSS v3 Base/Temporal Scores: 9.8 / 8.8
 Recommendations: Install or update to one of the following McAfee Agent versions:
  • 5.6.0 General Availability (GA)
  • 5.5.1 Hotfix 1267991 (HF1267991)
  • 5.0.6 Hotfix 1267994 (HF1267994)
 Security Bulletin Replacement: None
 Affected Software: McAfee Agent versions:
  • 5.5.x prior to 5.5.1 HF1267991
  • 5.0.x prior to 5.0.6 HF1267994
 Location of updated software: http://www.mcafee.com/us/downloads/downloads.aspx
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Article contents: Vulnerability Description
This vulnerability affects McAfee Agent only when remote logging is enabled. This option is disabled by default.

McAfee Agent offers the ability for the ePO administrator to enable remote logging on the targeted endpoints to aid troubleshooting. McAfee strongly recommends that remote logging is enabled only as required, and then returned to the disabled state.

When enabled, specially crafted HTTP headers may result in an attacker being able to execute their code through the McAfee Agent.

McAfee previously published this security bulletin with a score of 4.3 because we believed that it was only possible to crash the service, which would then restart automatically. Subsequent internal investigation revealed there is a possibility of an attacker creating a Remote Code Execution (RCE) exploit. Our internal investigation stopped when we realized it was theoretically possible and we backported this fix from 5.6.0 to 5.5.1 and 5.0.6.

NOTE: NIST reviewed our initial publication, and based on the information we made public, scored it as a 9.8.

CVE-2018-6703: Use After Free vulnerability in the remote logging functionality within McAfee Agent
Use After Free in remote logging (which is disabled by default) in McAfee Agent (MA) 5.x prior to 5.6.0 allows remote unauthenticated attackers to cause a Denial of Service and potentially a remote code execution via a specially crafted HTTP header sent to the remote logging service.

Affected Component:
McAfee Agent with remote logging enabled in the following versions:
  • 5.0.x
  • 5.5.x
To remediate this issue:
  • Upgrade McAfee Agent 5.5.1 or earlier to McAfee Agent 5.5.1 HF1267991, or McAfee Agent 5.6.0 (GA).
  • Upgrade McAfee Agent 5.0.6 and earlier to McAfee Agent 5.0.6 HF1267994, McAfee Agent 5.5.1 HF1267991, or McAfee Agent 5.6.0 (GA).
Go to the Product Downloads site, and download the applicable product update/hotfix file:
Product Version Type File Name Release Date
McAfee Agent 5.6.0 Minor  MA560WIN.zip
December 11, 2018
McAfee Agent 5.5.1 HF1267991 Hotfix MA551HF1267991LNX.zip
March 21, 2019
McAfee Agent 5.0.6 HF1267994 Hotfix MA506HF1267994LNX.zip
March 21, 2019
Download and Installation Instructions
See KB56057 for instructions on how to download McAfee products, documentation, updates, 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.
You are not vulnerable if the Enable remote access to log policy option is not enabled. This option is disabled by default.

You can check the status and disable the functionality through the ePO console:
  1. Go to the assigned policy type General for the product McAfee Agent.
  2. Go to the Logging tab.
  3. Disable Enable remote access to log.
If you want to continue to use the feature in older versions, configure your firewalls to limit access to the logging port to those internal machines that require access.

McAfee recommends that you only enable this feature when troubleshooting and then disable it when you are finished. 
By default, McAfee Agent is configured to only accept connections from the ePO server and agent handlers.

You can check this configuration through the ePO console:
  1. Go to the assigned policy type General for the product McAfee Agent.
  2. Go to the General tab.
  3. Enable Accept connections only from the ePO server.
McAfee credits Frank Cozijnsen of the KPN RED-team for reporting this flaw.
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 displays.
For McAfee Agent (command line):
Use the following instructions for endpoint or client-based products:
  1. Open a terminal.
  2. Enter the following command:
    • For Linux: /opt/McAfee/agent/bin/cmdagent -i
    • For Mac: /Library/McAfee/agent/bin/cmdagent -i
    • For Windows: C:\Program Files\McAfee\Agent\cmdagent -i

    The product version displays in the output.
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-2018-6703: Use After Free vulnerability in the remote logging functionality within McAfee Agent
Base Score 9.8
Attack Vector (AV) Network (N)
Attack Complexity (AC) Low (L)
Privileges Required (PR) None (N)
User Interaction (UI) None (N)
Scope (S) Unchanged (U)
Confidentiality (C) High (H)
Integrity (I) High (H)
Availability (A) High (H)
Temporal Score (Overall) 8.8
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?
Our key priority is the security of our customers. If a vulnerability is found within any McAfee 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, 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.
To contact Technical Support, log on to the ServicePortal and go to the Create a Service Request page at https://support.mcafee.com/ServicePortal/faces/serviceRequests/createSR:
  • If you are a registered user, type your User ID and Password, and then click Log In.
  • If you are not a registered user, click Register and complete the required fields. Your password and logon instructions will be emailed to you.
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 preceding 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 canceled at any time.

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