Departament d'Arquitectura de Computadors

Comparteix:

Alerta: Windows crashes degut a l'EDR CrowdStrike Falcon

19/07/2024

Ahir dijous dia 18 de juliol el lloc web de CrowdStrike va publicar una alerta notificant un problema al seu producte EDR Falcon Sensor que en certes circumstàncies fa fallar el sistema Windows i el deixa en la pantalla blava (coneguda com BSOD: Blue Screen Of Death). La indicència també ha estat recollida al portal dels Serveis TIC UPC.

CrowdStrike ha publicat la següent nota, que descriu el workaround que podeu aplicar immediatament al vostre equip en cas que el problema us afecti.

Summary

  • CrowdStrike is aware of reports of crashes on Windows hosts related to the Falcon Sensor.

 

Details

  • 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.
  • Windows hosts which are brought online after 0527 UTC will also not be impacted
  • This issue is not impacting Mac- or Linux-based hosts
  • Channel file "C-00000291*.sys" with timestamp of 0527 UTC or later is the reverted (good) version.
  • Channel file "C-00000291*.sys" with timestamp of 0409 UTC is the problematic version.

 

Current Action

  • CrowdStrike Engineering has identified a content deployment related to this issue and reverted those changes.

  • If hosts are still crashing and unable to stay online to receive the Channel File Changes, the following steps can be used to workaround this issue:

Workaround Steps for individual hosts:

  • Reboot the host to give it an opportunity to download the reverted channel file.  If the host crashes again, then:
    • Boot Windows into Safe Mode or the Windows Recovery Environment

    • Navigate to the %WINDIR%\System32\drivers\CrowdStrike directory

    • Locate the file matching “C-00000291*.sys”, and delete it.

    • Boot the host normally.

Note:  Bitlocker-encrypted hosts may require a recovery key.

Workaround Steps for public cloud or similar environment including virtual:

Option 1:

  • Detach the operating system disk volume from the impacted virtual server

  • Create a snapshot or backup of the disk volume before proceeding further as a precaution against unintended changes

  • Attach/mount the volume to to a new virtual server

  • Navigate to the %WINDIR%\\System32\drivers\CrowdStrike directory

  • Locate the file matching “C-00000291*.sys”, and delete it.

  • Detach the volume from the new virtual server

  • Reattach the fixed volume to the impacted virtual server

Option 2:

  • Roll back to a snapshot before 0409 UTC. 

Workaround Steps for Azure via serial

  1. Login to Azure console --> Go to Virtual Machines --> Select the VM
  2. Upper left on console --> Click : "Connect" --> Click --> Connect --> Click "More ways to Connect"  --> Click : "Serial Console"
  3. Step 3 : Once SAC has loaded, type in 'cmd' and press enter.
    1. type in 'cmd' command
    2. type in : ch -si 1
  4. Press any key (space bar). Enter Administrator credentials
  5. Type the following:
    1. bcdedit /set {current} safeboot minimal
    2. bcdedit /set {current} safeboot network
  6. Restart VM
  7. Optional: How to confirm the boot state? Run command:
    • wmic COMPUTERSYSTEM GET BootupState

For additional information please see this Microsoft article.

 

Latest Updates

  • 2024-07-19 05:30 AM UTC | Tech Alert Published.
  • 2024-07-19 06:30 AM UTC | Updated and added workaround details.
  • 2024-07-19 08:08 AM UTC | Updated
  • 2024-07-19 09:45 AM UTC | Updated

Keywords
EDR Windows BSOD