Detect Serverless in IBM QRadar
Adversaries may compromise serverless cloud infrastructure, such as Cloudflare Workers, AWS Lambda functions, or Google Apps Scripts, to proxy command-and-control (C2) communications between implants on victim systems and adversary-controlled backend servers. Because traffic destined for compromised serverless functions originates from subdomains of trusted cloud providers (e.g., *.workers.dev, *.execute-api.amazonaws.com, script.google.com), network-layer defenses relying on domain or IP reputation are largely ineffective. Detection pivots to behavioral analysis of victim-side telemetry: identifying processes on endpoints communicating with serverless platforms in patterns consistent with C2 beaconing (periodic connections, low-variance timing, small symmetric payloads), correlating process context with destination domains, and monitoring cloud audit logs for unauthorized modifications to serverless functions within environments the defender controls.
MITRE ATT&CK
- Tactic
- Resource Development
- Technique
- T1584 Compromise Infrastructure
- Sub-technique
- T1584.007 Serverless
- Canonical reference
- https://attack.mitre.org/techniques/T1584/007/
QRadar Detection Query
SELECT
sourceip,
username,
destinationhostname,
COUNT(*) AS connection_count,
COUNT(DISTINCT DATEFORMAT(starttime, 'yyyy-MM-dd HH')) AS hourly_buckets,
SUM(LONG(eventpayload)) AS total_bytes,
MIN(starttime) AS first_seen,
MAX(starttime) AS last_seen
FROM events
WHERE
LOGSOURCETYPENAME(devicetype) IN ('Palo Alto Networks Firewall', 'Check Point Firewall', 'Cisco ASA', 'Juniper Networks Firewall', 'Squid Proxy', 'Bluecoat Proxy')
AND (
destinationhostname MATCHES '.*\.workers\.dev'
OR destinationhostname MATCHES '.*\.cloudflareworkers\.com'
OR destinationhostname MATCHES '.*\.execute-api\.[a-z0-9-]+\.amazonaws\.com'
OR destinationhostname MATCHES '.*\.lambda-url\.[a-z0-9-]+\.amazonaws\.com'
OR destinationhostname = 'script.google.com'
OR destinationhostname MATCHES '.*\.cloudfunctions\.net'
OR destinationhostname MATCHES '.*\.run\.app'
OR destinationhostname MATCHES '.*\.azurewebsites\.net'
OR destinationhostname MATCHES '.*\.pages\.dev'
OR destinationhostname MATCHES '.*\.netlify\.app'
OR destinationhostname MATCHES '.*\.vercel\.app'
OR destinationhostname MATCHES '.*\.supabase\.co'
OR destinationhostname MATCHES '.*\.deno\.dev'
)
AND starttime > NOW() - 86400000
GROUP BY sourceip, username, destinationhostname
HAVING
connection_count >= 12
AND hourly_buckets >= 3
AND (total_bytes / connection_count) < 20480
ORDER BY connection_count DESCAQL rule targeting proxy and firewall log sources in QRadar. Aggregates outbound connections to serverless cloud domains per source IP and user over 24 hours, then filters for beaconing-consistent patterns: at least 12 connections spread across 3+ hourly buckets with low average bytes per connection. The bytes-per-connection threshold of 20480 captures both sent and received traffic.
Data Sources
Required Tables
False Positives & Tuning
- Internal developer tooling that regularly calls AWS Lambda or Google Cloud Functions for automation workflows
- Browser-based applications with polling mechanisms targeting Supabase or Vercel-hosted APIs on behalf of many users sharing a NAT IP
- Security products or SOAR platforms that probe cloud function endpoints as part of playbook execution or health monitoring
Other platforms for T1584.007
Testing Methodology
Validate this detection against 4 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Simulate C2 Beacon to Cloudflare Workers Domain
Expected signal: DeviceNetworkEvents: 15 ConnectionSuccess events from PowerShell.exe to httpbin.org, spaced ~30 seconds apart. Sysmon Event ID 3: Network connections with consistent DestinationPort=443 and DestinationHostname=httpbin.org. Inter-arrival time analysis will show MeanInterval ~30 seconds with low standard deviation (JitterCoefficient < 0.05).
- Test 2Non-Browser Process Connecting to AWS Lambda URL
Expected signal: Sysmon Event ID 3: Network connections with Image=C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe making POST requests to httpbin.org:443. DeviceNetworkEvents: InitiatingProcessFileName=powershell.exe, connection count=5 with small SentBytes values. Sysmon Event ID 22: DNS query for httpbin.org from powershell.exe.
- Test 3Enumerate and Test Unauthorized AWS Lambda Function (Controlled Lab)
Expected signal: AWS CloudTrail: ListFunctions and InvokeFunction API calls logged in CloudTrail with sourceIPAddress of the calling machine, userAgent=aws-cli, and requestParameters including the function name. If forwarded to a SIEM via CloudWatch/Kinesis, these appear in your cloud audit log index. EventName=InvokeFunction with errorCode absent indicates successful invocation.
- Test 4Deploy Test Cloudflare Worker via wrangler CLI (Simulates Infrastructure Compromise Foothold)
Expected signal: Cloudflare Audit Log: Worker script deployment event with actor email, source IP, and timestamp. If Cloudflare Logpush is configured to forward audit logs to your SIEM, the event appears as audit_log.action.type=deploy with resources referencing the worker name. Process telemetry: node.exe or cmd.exe spawning wrangler commands visible in Sysmon Event ID 1.
References (9)
- https://attack.mitre.org/techniques/T1584/007/
- https://www.bleepingcomputer.com/news/security/blackwater-malware-abuses-cloudflare-workers-for-c2-communication/
- https://blog.xpnsec.com/aws-lambda-redirector/
- https://awakesecurity.com/blog/threat-hunting-series-detecting-command-control-in-the-cloud/
- https://www.bleepingcomputer.com/news/security/hackers-abuse-google-apps-script-to-steal-credit-cards-bypass-csp/
- https://docs.aws.amazon.com/lambda/latest/dg/logging-using-cloudtrail.html
- https://developers.cloudflare.com/workers/observability/logging/
- https://cloud.google.com/logging/docs/audit/understanding-audit-logs
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1584.007/T1584.007.md
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