Managing Crowdstrike

CrowdStrike Falcon Management Skill

Manage and analyze CrowdStrike Falcon detections, hosts, incidents, and threat intelligence.

API Conventions

Authentication

All API calls use OAuth2 bearer tokens via Authorization: Bearer $CROWDSTRIKE_ACCESS_TOKEN -- injected automatically. Never hardcode tokens.

Base URL

https://api.crowdstrike.com

Core Helper Function

#!/bin/bash

cs_api() {
    local method="$1"
    local endpoint="$2"
    local data="${3:-}"

    if [ -n "$data" ]; then
        curl -s -X "$method" \
            -H "Authorization: Bearer $CROWDSTRIKE_ACCESS_TOKEN" \
            -H "Content-Type: application/json" \
            "https://api.crowdstrike.com${endpoint}" \
            -d "$data"
    else
        curl -s -X "$method" \
            -H "Authorization: Bearer $CROWDSTRIKE_ACCESS_TOKEN" \
            -H "Content-Type: application/json" \
            "https://api.crowdstrike.com${endpoint}"
    fi
}

Output Rules

• TOKEN EFFICIENCY: Extract only needed fields with jq
• Target <=50 lines per script output
• Always filter by relevant time range to avoid huge response sets
• Never dump full API responses

Discovery Phase

#!/bin/bash
echo "=== Host Inventory Summary ==="
cs_api GET "/devices/queries/devices-scroll/v1?limit=5000" \
    | jq '.meta.pagination.total as $total | "Total managed hosts: \($total)"' -r

echo ""
echo "=== Recent Detections (last 24h) ==="
cs_api GET "/detects/queries/detects/v1?filter=created_timestamp:>'$(date -u -v-1d +%Y-%m-%dT%H:%M:%SZ)'&limit=100" \
    | jq '.meta.pagination.total as $total | "Detections (24h): \($total)"' -r

echo ""
echo "=== Active Incidents ==="
cs_api GET "/incidents/queries/incidents/v1?filter=status:['20','25']&limit=50" \
    | jq '.meta.pagination.total as $total | "Open incidents: \($total)"' -r

Analysis Phase

Detection Overview

#!/bin/bash
echo "=== Critical/High Detections ==="
IDS=$(cs_api GET "/detects/queries/detects/v1?filter=max_severity_displayname:['Critical','High']+created_timestamp:>'$(date -u -v-7d +%Y-%m-%dT%H:%M:%SZ)'&limit=20" | jq -r '.resources[:20] | join(",")')

if [ -n "$IDS" ]; then
    cs_api POST "/detects/entities/summaries/GET/v1" "{\"ids\":[$(echo "$IDS" | sed 's/,/","/g' | sed 's/^/"/;s/$/"/')]}" \
        | jq -r '.resources[] | "\(.created_timestamp[0:16])\t\(.max_severity_displayname)\t\(.status)\t\(.device.hostname)\t\(.detection_id)"' \
        | column -t | head -20
fi

echo ""
echo "=== Detection Count by Severity ==="
cs_api GET "/detects/aggregates/detects/GET/v1" \
    -d '{"date_ranges":[{"from":"'"$(date -u -v-7d +%Y-%m-%dT%H:%M:%SZ)"'","to":"'"$(date -u +%Y-%m-%dT%H:%M:%SZ)"'"}],"field":"max_severity_displayname","type":"terms"}' \
    | jq -r '.resources[].buckets[] | "\(.label): \(.count)"'

Host Health

#!/bin/bash
echo "=== Hosts by Platform ==="
cs_api POST "/devices/aggregates/devices/GET/v1" \
    '[{"type":"terms","field":"platform_name"}]' \
    | jq -r '.resources[].buckets[] | "\(.label): \(.count)"'

echo ""
echo "=== Hosts with Stale Sensors (>7 days) ==="
cs_api GET "/devices/queries/devices/v1?filter=last_seen:<='$(date -u -v-7d +%Y-%m-%dT%H:%M:%SZ)'&limit=10" \
    | jq '.meta.pagination.total as $total | "Stale sensors: \($total)"' -r

echo ""
echo "=== Sensor Versions ==="
cs_api POST "/devices/aggregates/devices/GET/v1" \
    '[{"type":"terms","field":"agent_version","size":10}]' \
    | jq -r '.resources[].buckets[] | "\(.label): \(.count)"' | head -10

Incident Investigation

#!/bin/bash
INCIDENT_ID="${1:?Incident ID required}"

echo "=== Incident Details ==="
cs_api POST "/incidents/entities/incidents/GET/v1" "{\"ids\":[\"$INCIDENT_ID\"]}" \
    | jq '.resources[0] | {
        incident_id: .incident_id,
        status: .status,
        severity: .fine_score,
        start: .start,
        end: .end,
        hosts: (.hosts | length),
        tactics: .tactics,
        techniques: .techniques
    }'

echo ""
echo "=== Associated Detections ==="
cs_api GET "/incidents/queries/behaviors/v1?filter=incident_id:'$INCIDENT_ID'" \
    | jq -r '.resources[:10][]'

Output Format

Present results as a structured report:

Managing Crowdstrike Report
═══════════════════════════
Resources discovered: [count]

Resource       Status    Key Metric    Issues
──────────────────────────────────────────────
[name]         [ok/warn] [value]       [findings]

Summary: [total] resources | [ok] healthy | [warn] warnings | [crit] critical
Action Items: [list of prioritized findings]

Target ≤50 lines of output. Use tables for multi-resource comparisons.

Anti-Hallucination Rules

1. NEVER assume resource names — always discover via CLI/API in Phase 1 before referencing in Phase 2.
2. NEVER fabricate metric names or dimensions — verify against the service documentation or --help output.
3. NEVER mix CLI commands between service versions — confirm which version/API you are targeting.
4. ALWAYS use the discovery → verify → analyze chain — every resource referenced must have been discovered first.
5. ALWAYS handle empty results gracefully — an empty response is valid data, not an error to retry.

Counter-Rationalizations

Common Pitfalls

• Two-step entity lookup: Query endpoints return IDs only -- must call entity endpoints to get details
• FQL syntax: Filter queries use Falcon Query Language with single quotes for values
• Rate limits: 6000 requests/min for most endpoints -- stagger parallel calls
• Pagination: Default limit varies by endpoint -- always specify limit parameter
• OAuth2 token refresh: Tokens expire after 30 minutes -- refresh via /oauth2/token