Once in a Blue Screen
Once in a Blue Screen
What Happened: CrowdStrike Windows Crash on July 19, 2024
On July 19, 2024, CrowdStrike experienced a global service disruption caused by a logic error in a sensor configuration update. This impacted Windows systems running Falcon sensor version 7.11 and above, resulting in system crashes (BSOD - Blue Screen of Death).
The issue was identified and resolved within 78 minutes. It stemmed from a configuration file (specifically, Channel File 291) that was automatically deployed to Windows systems, causing critical faults during execution. CrowdStrike has confirmed this was not a cyberattack, and a root cause analysis is in progress to prevent future incidents.
Impact
All systems that were:
- Running Windows Falcon Sensor 7.11+
- Online between 09:30 AM and 11:00 AM IST (Chennai Time)
…were potentially affected, including some user endpoints that crashed due to a misconfiguration in Falcon’s behavioral detection mechanism.
My PC at work
Technical Details
A rule update meant to detect malicious use of named pipes introduced a logic error that led to system crashes. This update was part of Channel File 291 (C-00000291-.sys), a system-level driver responsible for behavioral analytics on interprocess communication.
- Channel Files are part of Falcon’s real-time protection logic, updated multiple times per day.
- These files live under:
C:\Windows\System32\drivers\CrowdStrike\
The faulty logic in Channel File 291 caused the Falcon sensor to misinterpret valid system behavior, triggering BSODs.
The affected file has now been rolled back. No other Channel File was involved.
Solution
If your system is crashing and you’re unable to boot normally:
Step-by-Step Recovery
- Reboot your system while connected to a wired network (Ethernet) for faster internet recovery.
- If the system crashes again, follow the below steps:
Manual Deletion of the Faulty File
Boot into Safe Mode or use Windows Recovery Environment:
- Use “Safe Mode with Networking” if possible.
- BitLocker-protected systems may ask for a recovery key.
Navigate to the Falcon driver folder:
1
2
C:
cd \windows\system32\drivers\crowdstrike
Delete the file matching:
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C-00000291*.sys
Do not delete any other files. Only the above.
Final Step: Cold Boot
- Shut down the system completely (not restart).
- Power it back on from the off state.
The Falcon sensor will download the reverted (safe) Channel File on next startup.
For Teams and IT Managers
Your goal is clarity, not chaos. Here are key takeaways to share with your users or stakeholders:
- This was a CrowdStrike error, not a cyberattack.
- The issue was fixed within a short time frame.
- Affected systems can be remediated using Safe Mode.
- A full RCA (Root Cause Analysis) is ongoing.
Avoid reacting to sensational reports. Focus on remediation and communication with your internal users.
Official Sources
For ongoing updates and technical context, refer to: