ThreatFox: Cobalt Strike IOCs

Hunt Hypothesis

This hunt detects adversary behavior involving the deployment of Cobalt Strike beacons and their associated infrastructure indicators to establish persistent command-and-control channels within the network. A SOC team should proactively hunt for these IOCs in Azure Sentinel because Cobalt Strike is a widely used post-exploitation tool that often indicates an advanced attacker has already achieved initial access and is actively mapping or moving laterally across the environment.

IOC Summary

Malware Family: Cobalt Strike Total IOCs: 9 IOC Types: ip:port

Type	Value	Threat Type	First Seen	Confidence
ip:port	`43[.]129[.]250[.]96:22`	botnet_cc	2026-07-30	100%
ip:port	`43[.]129[.]250[.]96:80`	botnet_cc	2026-07-30	100%
ip:port	`43[.]129[.]250[.]96:8080`	botnet_cc	2026-07-30	100%
ip:port	`43[.]129[.]250[.]96:443`	botnet_cc	2026-07-30	100%
ip:port	`54[.]178[.]100[.]27:8080`	botnet_cc	2026-07-30	100%
ip:port	`54[.]178[.]100[.]27:443`	botnet_cc	2026-07-30	100%
ip:port	`54[.]178[.]100[.]27:80`	botnet_cc	2026-07-30	100%
ip:port	`107[.]172[.]199[.]28:80`	botnet_cc	2026-07-30	100%
ip:port	`107[.]172[.]199[.]28:8080`	botnet_cc	2026-07-30	100%

KQL: Ip Hunt

// Hunt for network connections to known malicious IPs
// Source: ThreatFox - Cobalt Strike
let malicious_ips = dynamic(["107.172.199.28", "54.178.100.27", "43.129.250.96"]);
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(["107.172.199.28", "54.178.100.27", "43.129.250.96"]);
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 rule, including suggested filters and exclusions tailored for an enterprise environment:

Scenario: DevOps CI/CD Pipeline Execution
- Context: Internal build servers (e.g., Jenkins, GitLab Runner) frequently execute the beacon executable or similar C2 payloads as part of automated security testing scripts. These scripts often utilize Cobalt Strike’s beacon for vulnerability scanning simulations within the development subnet.
- Filter/Exclusion: Exclude traffic and process execution where the source IP belongs to the dedicated Dev-Subnet (e.g., 10.20.x.x) AND the parent process is a known CI tool (e.g., jenkins.exe, gitlab-runner.exe). Additionally, filter out events occurring during scheduled maintenance windows (e.g., 02:00–04:00 UTC).
Scenario: Endpoint Security Agent Updates
- Context: Enterprise EDR solutions (such as CrowdStrike Falcon or Microsoft Defender for Endpoint) often use Cobalt Strike components internally for their own telemetry collection or agent communication modules. When the agent updates its configuration, it may spawn processes matching the rule’s IOCs.
- Filter/Exclusion: Create an exclusion list based on the Parent Process Name. Exclude any event where the parent process is C-Host.exe (CrowdStrike), MsMpEng.exe (Defender), or SentinelOneAgent.exe. Ensure the hash of the child process matches a known “Good Hash” registry entry maintained by the security team.
Scenario: Scheduled Internal Vulnerability Scans
- Context: The internal Security Operations team runs weekly vulnerability assessments using Tenable Nessus or Qualys, which often deploy Cobalt Strike beacons to validate