TheXDR Collectoron a Windows endpoint collects logs (e.g., Windows Event Logs) and forwards them to the Cortex XDR console for analysis. An OS upgrade can impact the collector’s functionality, particularly if it affects log formats, sizes, or compatibility. If log events are no longer observed after the upgrade, the issue likely relates to a change in how logs are processed or transmitted. Cortex XDR imposes limits on log event sizes to ensure efficient ingestion and processing.

Correct Answer Analysis (A):The probable cause is thatthe log events are greater than 5MB. Cortex XDR has a size limit for individual log events, typically around 5MB, to prevent performance issues during ingestion. An OS upgrade may change the way logs are generated (e.g., increasing verbosity or adding metadata), causing events to exceed this limit. If log events are larger than 5MB, the XDR Collector will drop them, resulting in no logs being observed in the console.

Why not the other options?

B. They are in Winlogbeat format: Winlogbeat is a supported log shipper for collecting Windows Event Logs, and the XDR Collector is compatible with this format. The format itself is not the issue unless misconfigured, which is not indicated.

C. They are in Filebeat format: Filebeat is also supported by the XDR Collector for file-based logs. The format is not the likely cause unless the OS upgrade changed the log source, which is not specified.

D. They are less than 1MB: There is no minimum size limit for log events in Cortex XDR, so being less than 1MB would not cause logs to stop appearing.

Exact Extract or Reference:

TheCortex XDR Documentation Portalexplains log ingestion limits: “Individual log events larger than 5MB are dropped by the XDR Collector to prevent ingestion issues, which may occur after changes like an OS upgrade” (paraphrased from the XDR Collector Troubleshooting section). TheEDU-260: Cortex XDR Prevention and Deploymentcourse covers log collection issues, stating that “log events exceeding 5MB are not ingested, a common issue after OS upgrades thatincrease log size” (paraphrased from course materials). ThePalo Alto Networks Certified XDR Engineer datasheetincludes “maintenance and troubleshooting” as a key exam topic, encompassing log ingestion issues.