ThreatFox: Cobalt Strike IOCs

Hunt Hypothesis

This hunt targets adversary behavior involving the deployment of Cobalt Strike beacons to establish persistent command-and-control channels and facilitate lateral movement across the network. Proactively hunting for these specific IOCs in Azure Sentinel is critical because early detection of this sophisticated malware can prevent attackers from establishing a foothold before they execute broader compromise strategies.

IOC Summary

Malware Family: Cobalt Strike Total IOCs: 10 IOC Types: ip:port

Type	Value	Threat Type	First Seen	Confidence
ip:port	`120[.]26[.]208[.]96:33060`	botnet_cc	2026-07-21	100%
ip:port	`120[.]26[.]208[.]96:22`	botnet_cc	2026-07-21	100%
ip:port	`120[.]26[.]208[.]96:61004`	botnet_cc	2026-07-21	100%
ip:port	`117[.]72[.]39[.]83:3306`	botnet_cc	2026-07-21	100%
ip:port	`43[.]165[.]188[.]19:8080`	botnet_cc	2026-07-21	100%
ip:port	`43[.]155[.]169[.]245:5353`	botnet_cc	2026-07-21	100%
ip:port	`43[.]165[.]188[.]19:80`	botnet_cc	2026-07-21	100%
ip:port	`43[.]165[.]188[.]19:443`	botnet_cc	2026-07-21	100%
ip:port	`43[.]155[.]169[.]245:8080`	botnet_cc	2026-07-21	100%
ip:port	`43[.]155[.]169[.]245:22`	botnet_cc	2026-07-21	100%

KQL: Ip Hunt

// Hunt for network connections to known malicious IPs
// Source: ThreatFox - Cobalt Strike
let malicious_ips = dynamic(["43.165.188.19", "43.155.169.245", "120.26.208.96", "117.72.39.83"]);
CommonSecurityLog
| where DestinationIP in (malicious_ips) or SourceIP in (malicious_ips)
| project TimeGenerated, SourceIP, DestinationIP, DestinationPort, DeviceAction, Activity
| order by TimeGenerated desc

KQL: Ip Hunt Device

// Hunt in Defender for Endpoint network events
let malicious_ips = dynamic(["43.165.188.19", "43.155.169.245", "120.26.208.96", "117.72.39.83"]);
DeviceNetworkEvents
| where RemoteIP in (malicious_ips)
| project Timestamp, DeviceName, RemoteIP, RemotePort, InitiatingProcessFileName, ActionType
| order by Timestamp desc

Required Data Sources

Sentinel Table	Notes
`CommonSecurityLog`	Ensure this data connector is enabled
`DeviceNetworkEvents`	Ensure this data connector is enabled

References

ThreatFox — Cobalt Strike

False Positive Guidance

Here are 5 specific false positive scenarios for the ThreatFox: Cobalt Strike IOCs detection rule in an enterprise environment, along with suggested filters or exclusions:

Legitimate IT Asset Inventory Scans
- Scenario: Automated inventory tools like ** Lansweeper**, SolarWinds NPM, or Microsoft Endpoint Configuration Manager (MECM) frequently deploy lightweight agents that establish persistent connections and execute scripts to gather hardware/software telemetry. These activities often mimic Cobalt Strike’s beacon behavior, triggering alerts on standard ports (e.g., 80/443) with similar User-Agent strings or process execution patterns.
- Suggested Filter: Exclude traffic originating from known management subnets (e.g., 10.20.50.0/24) and specifically whitelist the process names of approved inventory agents (LansweeperAgent.exe, ccmexec.exe) when communicating with internal asset servers.
Scheduled Patch Management Deployments
- Scenario: During nightly maintenance windows, tools like WSUS, Ivanti Endpoint Manager, or Ansible Tower push updates to thousands of endpoints. These deployments often involve the execution of temporary PowerShell scripts (powershell.exe -EncodedCommand) and the creation of new service entries that resemble Cobalt Strike’s lateral movement techniques (e.g., Beacon service installation).
- Suggested Filter: Create a time-based exclusion for alerts occurring between 02:00 and 05:00 UTC on weekdays, specifically targeting processes launched by the “SYSTEM” account or specific Service Accounts (e.g., svc_patch_deploy) that match known patch management tool signatures.
Enterprise Application Performance Monitoring (APM)
- Scenario: APM solutions such as Dynatrace, New Relic, or **AppD