Detect Virtual Private Server in CrowdStrike LogScale
Adversaries may rent Virtual Private Servers (VPSs) to stage malicious infrastructure including command-and-control (C2) servers, phishing pages, payload delivery endpoints, and exfiltration destinations. VPS providers offer rapid provisioning, geographic flexibility, and—when chosen carefully—minimal registration requirements, making attribution difficult. Because VPS-hosted IPs typically carry commercial hosting ASN reputation rather than residential or known-malicious reputation, they can evade naive geo-blocking and ASN-based controls. Real-world actors documented using this technique include Gamaredon, APT28, LAPSUS$, Ember Bear (GRU Unit 29155), HAFNIUM, APT42, Moonstone Sleet, and Contagious Interview. Detection from a defender perspective focuses on three observable effects: outbound C2 beaconing FROM compromised endpoints TO VPS-hosted IPs, inbound attack traffic (scanning, exploit delivery, phishing redirectors) FROM VPS IP ranges, and identity-based signals such as authentication attempts from datacenter IP space. Because T1583.003 is a Resource Development technique (TA0042), it is not directly observable on victim endpoints—detection is necessarily inferential, relying on behavioral patterns that betray VPS-based infrastructure in use.
MITRE ATT&CK
- Tactic
- Resource Development
- Technique
- T1583 Acquire Infrastructure
- Sub-technique
- T1583.003 Virtual Private Server
- Canonical reference
- https://attack.mitre.org/techniques/T1583/003/
LogScale Detection Query
// T1583.003 — VPS C2 Beaconing: repeated outbound connections from non-browser processes
#event_simpleName=NetworkConnectIP4
// Exclude RFC 1918, loopback, and link-local
| !match(RemoteAddressIP4, regex="^(10\\.|172\\.(1[6-9]|2[0-9]|3[01])\\.|192\.168\\.|127\\.|169\.254\\.)")
| RemoteAddressIP4 != "::1"
// Exclude browsers and noisy system processes
| !match(ImageFileName, regex="(?i)(chrome|firefox|msedge|MicrosoftEdgeCP|iexplore|brave|opera|safari|waterfox|svchost|MsMpEng|wuauclt|TrustedInstaller|msiexec|ccmexec|teams|OneDrive)\.exe$")
// Aggregate connections per host/user/process/destination within 1-hour buckets
| bucket(field=@timestamp, span=1h)
| groupBy(
[ComputerName, UserName, ImageFileName, CommandLine, RemoteAddressIP4, @timestamp],
function=[
count(as=ConnectionCount),
count(RemotePort, distinct=true, as=UniqueRemotePorts)
]
)
// Apply minimum connection threshold (beacon filter)
| ConnectionCount >= 12
// Compute connections-per-minute rate
| ConnectionsPerMinute := round(ConnectionCount / 60.0, 2)
// Assign beacon risk tier
| BeaconRisk := case {
ConnectionCount >= 50 AND UniqueRemotePorts <= 1 => "CRITICAL - Highly Regular Single-Port Beaconing",
ConnectionCount >= 30 AND UniqueRemotePorts <= 2 => "HIGH - Low Port Variance Repetitive Connections",
ConnectionCount >= 20 => "MEDIUM - Elevated Outbound Connection Frequency",
* => "LOW - Above Threshold Outbound Frequency"
}
// Assign numeric risk score for sorting
| RiskScore := case {
BeaconRisk = "CRITICAL - Highly Regular Single-Port Beaconing" => 4,
BeaconRisk = "HIGH - Low Port Variance Repetitive Connections" => 3,
BeaconRisk = "MEDIUM - Elevated Outbound Connection Frequency" => 2,
* => 1
}
| sort(RiskScore, ConnectionCount, order=desc)
| select([ComputerName, UserName, ImageFileName, CommandLine, RemoteAddressIP4,
ConnectionCount, ConnectionsPerMinute, UniqueRemotePorts,
BeaconRisk, RiskScore, @timestamp])CrowdStrike LogScale (CQL) query detecting C2 beaconing to VPS-hosted infrastructure using Falcon sensor NetworkConnectIP4 events. Filters out RFC 1918 / loopback / link-local destinations and known-safe browser and system processes, then groups by 1-hour buckets across (host, user, process, destination IP). Applies a 12-connection minimum threshold and computes the same four-tier beacon risk classification and numeric risk score as the reference SPL. Requires CrowdStrike Falcon EDR with network telemetry enabled and logs forwarded to a LogScale repository containing Falcon endpoint events.
Data Sources
Required Tables
False Positives & Tuning
- CrowdStrike Falcon sensor itself and other endpoint security agents (Carbon Black, SentinelOne) generate frequent internal telemetry connections; however, these are typically excluded by the process name filter — confirm the sensor process names are covered in the exclusion regex and update as product versions change.
- Developer workstations running Docker Desktop, Kubernetes, or local service meshes generate high-frequency connections to localhost-forwarded ports that may appear as repeated connections to specific IPs; review destination IPs in alerts and exclude known developer toolchain destinations.
- Automated test frameworks (Selenium Grid, Playwright test runners, JMeter load generators) running on endpoint devices produce rapid repetitive outbound connections as part of normal test execution; correlate with CI/CD schedules and exclude test-runner process names in non-production environments.
Other platforms for T1583.003
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 via PowerShell HTTP Check-in to VPS-like Endpoint
Expected signal: Sysmon Event ID 1: Process Create with Image=powershell.exe and CommandLine containing '-WindowStyle Hidden' and 'Invoke-WebRequest'. Sysmon Event ID 3: 15 network connections from powershell.exe to 127.0.0.1:8443 at approximately 5-second intervals. PowerShell ScriptBlock Log Event ID 4104 with the full script body.
- Test 2Simulate VPS Payload Download via LOLBin (certutil)
Expected signal: Sysmon Event ID 1: Process Create with Image=certutil.exe and CommandLine containing '-urlcache' and '-f'. Sysmon Event ID 3: Network Connection from certutil.exe to 127.0.0.1:8080. Sysmon Event ID 11: File Create attempt for %TEMP%\df00tech-vps-test.exe (may not succeed if no listener). Security Event ID 4688 (if command line auditing enabled).
- Test 3Simulate VPS-based Reconnaissance Inbound Scan Detection (nmap from localhost)
Expected signal: Linux auditd: syscall execve for nmap with full argument list. Syslog: nmap process execution. Network: TCP SYN packets to localhost ports 22, 80, 443, 3389, 8080, 8443. If monitoring inbound scan patterns on perimeter, this generates SYN packets with no corresponding application connection.
- Test 4Simulate Azure AD Authentication from VPS IP Range via PowerShell Graph API Call
Expected signal: Sysmon Event ID 1: Process Create with Image=powershell.exe. Sysmon Event ID 3: Network Connection from powershell.exe to login.microsoftonline.com:443. Sysmon Event ID 22 (DNS Query): DNS resolution of login.microsoftonline.com. PowerShell ScriptBlock Log Event ID 4104.
References (12)
- https://attack.mitre.org/techniques/T1583/003/
- https://documents.trendmicro.com/assets/wp/wp-criminal-hideouts-for-lease.pdf
- https://michaelkoczwara.medium.com/cobalt-strike-c2-hunting-with-shodan-c448d501a6e2
- https://threatconnect.com/blog/infrastructure-research-hunting/
- https://cloud.google.com/blog/topics/threat-intelligence/scandalous-external-detection-using-network-scan-data-and-automation/
- https://www.cisa.gov/news-events/cybersecurity-advisories/aa24-249a
- https://www.microsoft.com/en-us/security/blog/2022/03/22/dev-0537-criminal-actor-targeting-organizations-for-data-exfiltration-and-destruction/
- https://unit42.paloaltonetworks.com/unit-42-gamaredon-group-russia-linked/
- https://www.sentinelone.com/labs/winter-vivern-all-you-need-is-one-side-loading-and-a-good-lure/
- https://www.ic3.gov/Media/News/2022/220211.pdf
- https://learn.microsoft.com/en-us/azure/sentinel/understand-threat-intelligence
- https://learn.microsoft.com/en-us/defender-endpoint/advanced-hunting-devicenetworkevents-table
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