CrowdStrike Falcon Sensor High CPU Usage: Causes and Fixes
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A host where the Falcon sensor is pegging a CPU core looks alarming, but it is rarely a sign that the sensor itself is broken. In the large majority of documented cases, high sensor CPU usage means the sensor is doing exactly what it is designed to do: inspecting file, process, and network activity, just at a volume that a specific workload, a conflicting second security agent, or a specific sensor build has pushed higher than normal. Treating every high-CPU host the same way, by disabling protection or applying broad exclusions, either leaves the host unprotected or creates blind spots that outlast the problem that caused them.
This is a troubleshooting guide for a sensor that is already installed and already misbehaving, not a deployment or tuning guide written in advance of rollout. If the host is also showing as online while not enforcing detections at all, that is a different problem, Reduced Functionality Mode, covered separately in the RFM diagnosis guide. This guide assumes the sensor is actively running and enforcing, and CPU usage is the symptom you are chasing.
Causes: what actually drives Falcon sensor CPU up
High CPU usage from the Falcon sensor traces back to one of a small number of real, documented causes. Distinguishing between them matters because the fix for one does nothing for another, and applying the wrong one wastes time while the host keeps running hot.
The common thread across all three is that the sensor is either processing more events than usual, processing the same events twice, or running a specific build with a logic defect. None of these means the sensor needs to be disabled; each has a targeted fix.
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Diagnostics: identifying which cause applies to your host
Do not jump straight to exclusions based on a guess. Confirm what the sensor is actually spending CPU on before changing configuration, since the three causes above call for entirely different responses.
Start with process-level accounting rather than a single point-in-time CPU percentage, since a brief spike during a scheduled scan or update looks identical to sustained high usage in a snapshot but requires no action.
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Fixes: resolving high CPU without disabling protection
The fix depends entirely on which cause the diagnostics point to. Across all three, the objective is the same: keep the sensor fully enforcing while removing whatever is driving the excess load, using the narrowest change that solves the actual problem.
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Validation: confirming CPU usage actually normalized
An exclusion or update that looks correct on paper can still fail to resolve the issue if it was scoped to the wrong path, or if a second, unidentified cause was also contributing. Validate against the same measurement you used to diagnose the problem, not just by assuming the change worked.
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Failure cases: when the standard fixes do not resolve high CPU
Some high-CPU cases do not resolve cleanly with an exclusion or a version update, and recognizing these patterns early avoids repeated, ineffective changes.
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Escalation criteria: when to open a CrowdStrike support case
Most high-CPU cases resolve through workload identification and a scoped exclusion, agent conflict removal, or a routine sensor update. Escalate to CrowdStrike support when the following apply, and bring the diagnostic detail with you rather than opening a case with only the symptom.
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The bottom line
High CPU from the Falcon sensor is a symptom with a small number of real causes, and the right response depends entirely on which one applies: a scoped exclusion for a specific high-churn workload, full removal of a conflicting second security agent, or a sensor version update for a known build defect. Broad exclusions and disabling the sensor both solve the CPU problem while creating a worse one, so diagnose before acting, and validate against the same measurement afterward rather than assuming a change worked. If this same host has also shown up as online but not enforcing detections at all, that is Reduced Functionality Mode, a separate condition covered in the RFM diagnosis guide. For teams still evaluating EDR platforms rather than troubleshooting an existing deployment, the best EDR platforms roundup covers that decision separately from this operational problem.
Frequently asked questions
Why is the CrowdStrike Falcon sensor using so much CPU on one host but not others?
The most common reason is that the affected host runs a workload the sensor has to inspect heavily, such as a build server compiling large volumes of source files, a database engine with high-churn data directories, or a backup job touching millions of files in a short window. The sensor is not malfunctioning in this case; it is doing more work because the host is generating more events for it to evaluate. Hosts without that workload will not show the same CPU pattern even on an identical sensor version, which is why comparing CPU usage across a fleet running the same build is a useful first diagnostic step.
Can running another antivirus or EDR product alongside CrowdStrike Falcon cause high CPU usage?
Yes. When a second real-time antivirus or endpoint protection agent runs on the same host as Falcon, both engines intercept the same file and process I/O independently, and each file operation gets evaluated twice. This roughly doubles the interception overhead on every file touch, which shows up as sustained CPU load from both agents. CrowdStrike's own deployment guidance calls for removing legacy antivirus before installing Falcon specifically to avoid this, so a host running both is usually a leftover from migration rather than an intentional configuration.
What is falcon-sensor-bpf and why does it show high CPU on Linux hosts?
On Linux, the Falcon sensor uses a BPF-based (Berkeley Packet Filter) kernel subsystem, often visible in process listings as falcon-sensor-bpf, to observe system call activity for detection purposes. High CPU attributed to this component is typically traced to one specific noisy workload on the host, such as a process generating an unusually high rate of file or process system calls, rather than a fleet-wide sensor problem. Identifying and excluding that one workload's path or process, rather than broadening exclusions across the host, is the documented fix.
Has CrowdStrike shipped a sensor update that itself caused high CPU usage?
Yes, this has happened. Reporting on a prior CrowdStrike sensor issue described a logic error introduced by a change to memory-scan detection logic that caused CsFalconService to consume up to 100 percent of a single CPU core on affected Windows sensor builds, with a reboot restoring normal operation and CrowdStrike resolving the underlying issue by rolling back the detection logic change. This is a distinct incident from a workload-driven CPU spike: it affected a specific sensor build regardless of what was running on the host, which is why checking your current sensor version against CrowdStrike's release notes is worth doing before assuming the cause is local.
What is the difference between machine-learning, IOA, and sensor visibility exclusions in CrowdStrike Falcon?
These are three separate exclusion types with different scope and risk. A machine-learning exclusion stops the sensor's ML-based file scanning engine from evaluating files in a given path, useful for a known-good but high-churn location like a build output directory. An indicator-of-attack (IOA) exclusion suppresses specific behavioral detections for a given process or path, useful when legitimate software's normal behavior trips a behavioral rule. A sensor visibility exclusion is the broadest: it removes a path or process from sensor monitoring almost entirely. Because visibility exclusions create the largest blind spot, CrowdStrike and independent guidance both recommend using the narrowest exclusion type that solves the actual problem, not defaulting to visibility exclusions.
When should I open a CrowdStrike support case for high CPU usage instead of applying exclusions myself?
Escalate when a scoped exclusion for the workload you have identified does not bring CPU usage down to a reasonable level, when high CPU is affecting hosts across a build or OS version with no common workload driving it (which points at a sensor bug rather than a local condition), or when you cannot identify what the sensor is processing heavily even after checking process-level CPU accounting and recent file or process activity on the host. Include the sensor version, OS build, the diagnostic output showing which process is consuming CPU, and what exclusions or updates you have already tried in the case.
Sources & references
- Inventive HQ: Fix falcon-sensor-bpf High CPU Usage (CrowdStrike Falcon Linux & Windows)
- Inventive HQ: CrowdStrike Exclusions: Configure File, Folder & Process Exceptions
- The Stack: CrowdStrike bug maxes out 100% of CPU, requires Windows reboots
- Duke OIT: Troubleshooting the CrowdStrike Falcon Sensor for Linux
- Duke OIT: Troubleshooting the CrowdStrike Falcon Sensor for Windows
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