Remediation and Guidance Hub: Falcon Content Update for Windows Hosts

Page last updated 2024-07-22 1528 UTC

CrowdStrike is actively assisting customers affected by a defect in a recent content update for Windows hosts. Mac and Linux hosts were not impacted. The issue has been identified and isolated, and a fix has been deployed. This was not a cyberattack.

Customers are advised to check the support portal for updates. We will also continue to provide the latest information here and on our blog as it’s available. We recommend organizations verify they are communicating with CrowdStrike representatives through official channels.

We assure our customers that CrowdStrike is operating normally and this issue does not affect our Falcon platform systems. If your systems are operating normally, there is no impact to their protection if the Falcon sensor is installed.

We understand the gravity of this situation and are deeply sorry for the inconvenience and disruption. Our team is fully mobilized to ensure the security and stability of CrowdStrike customers.

Overview

Statement from our CEO

Sent 2024-07-19 1930 UTC

Valued Customers and Partners,

I want to sincerely apologize directly to all of you for the outage. All of CrowdStrike understands the gravity and impact of the situation. We quickly identified the issue and deployed a fix, allowing us to focus diligently on restoring customer systems as our highest priority.

The outage was caused by a defect found in a Falcon content update for Windows hosts. Mac and Linux hosts are not impacted. This was not a cyberattack.

We are working closely with impacted customers and partners to ensure that all systems are restored, so you can deliver the services your customers rely on.

CrowdStrike is operating normally, and this issue does not affect our Falcon platform systems. There is no impact to any protection if the Falcon sensor is installed. Falcon Complete and Falcon OverWatch services are not disrupted.

We will provide continuous updates through our Support Portal at https://supportportal.crowdstrike.com/s/login/.

We have mobilized all of CrowdStrike to help you and your teams. If you have questions or need additional support, please reach out to your CrowdStrike representative or Technical Support.

We know that adversaries and bad actors will try to exploit events like this. I encourage everyone to remain vigilant and ensure that you’re engaging with official CrowdStrike representatives. Our blog and technical support will continue to be the official channels for the latest updates.

Nothing is more important to me than the trust and confidence that our customers and partners have put into CrowdStrike. As we resolve this incident, you have my commitment to provide full transparency on how this occurred and steps we’re taking to prevent anything like this from happening again.

George Kurtz

CrowdStrike Founder and CEO

Technical Details

• Technical Details on the outage can be found here: Read the blog Published 2024-07-19 0100 UTC
• We assure our customers that CrowdStrike is operating normally and this issue does not affect our Falcon platform systems. If your systems are operating normally, there is no impact to their protection if the Falcon Sensor is installed. Falcon Complete and OverWatch services are not disrupted by this incident.
• CrowdStrike has identified the trigger for this issue as a Windows sensor related content deployment and we have reverted those changes. The content is a channel file located in the %WINDIR%\System32\drivers\CrowdStrike directory.
• Channel file “C-00000291*.sys” with timestamp of 2024-07-19 0527 UTC or later is the reverted (good) version.
• Channel file “C-00000291*.sys” with timestamp of 2024-07-19 0409 UTC is the problematic version.
• Note: It is normal for multiple “C-00000291*.sys files to be present in the CrowdStrike directory – as long as one of the files in the folder has a timestamp of 05:27 UTC or later, that will be the active content.
• Symptoms include hosts experiencing a bugcheck\blue screen error related to the Falcon Sensor.
• Windows hosts which have not been impacted do not require any action as the problematic channel file has been reverted.

Non-Impacted Hosts

• Windows hosts which are brought online after 2024-07-19 0527 UTC will not be impacted
• Windows hosts installed and provisioned after 2024-07-19 0527 UTC are not impacted Updated 2024-07-21 1435 UTC
• This issue is not impacting Mac- or Linux-based hosts

How do I Identify Impacted Hosts?

How do I Identify Impacted Hosts via Advanced Event Search Query?
Updated 2024-07-22 0139 UTC

The queries utilized by the dashboards are listed at the bottom of the appropriate dashboard KB articles.

How do I Identify Impacted Hosts via Dashboard?
Updated 2024-07-22 0139 UTC

An updated granular dashboard is available that displays the Windows hosts impacted by the content update defect described in this Tech Alert. See Granular status dashboards to identify Windows hosts impacted by content issue (v8.6) (pdf) or log in to view in the support portal. Note that the queries utilized by the dashboards are listed at the bottom of the appropriate dashboard KB articles.

How do I Remediate Impacted Hosts?

If hosts are still crashing and unable to stay online to receive the Channel File update, the remediation steps below can be used.

How do I Remediate Individual Hosts?
Updated 2024-07-21 0932 UTC

• Reboot the host to give it an opportunity to download the reverted channel file. We strongly recommend putting the host on a wired network (as opposed to WiFi) prior to rebooting as the host will acquire internet connectivity considerably faster via ethernet.
• If the host crashes again on reboot:
• Option 1 – Manual
• Please see this Microsoft article for detailed steps.
• Note: Bitlocker-encrypted hosts may require a recovery key.
• Review the following video on CrowdStrike Host Self-Remediation for Remote Users. Follow the instructions contained within the video if directed to do so by your organization’s IT department. Updated 2024-07-22 1510 UTC
• Option 2 – Automated via bootable USB key
• Follow the instructions in this KB article (pdf) or log in to view in the support portal.
• Note: Bitlocker-encrypted hosts may require a recovery key.

How do I Recover Bitlocker Keys?
Updated 2024-07-21 1810 UTC

How to Recover Cloud-Based Environment Resources

Third Party Vendor Information
Updated 2024-07-20 2259 UTC

Additional Resources

• Statement from our CEO
  Published 2024-07-19 1915 UTC
• Falcon Sensor Content issue Likely Used to Target CrowdStrike Customers
  Published 2024-07-19 2030 UTC
• Technical Details: Falcon Content Update for Windows Hosts
  Published 2024-07-19 0100 UTC
• Likely eCrime Actor Uses Filenames Capitalizing on Falcon Sensor Content Issues in Operation Targeting LATAM-based CrowdStrike Customers
  Published 2024-07-20 0145 UTC