ThreatFox: Unknown malware IOCs

Hunt Hypothesis

This detection rule identifies potential compromise by correlating network and endpoint telemetry against eleven specific indicators of unknown malware activity within the Azure environment. Proactively hunting for these signals is critical to uncover stealthy threats that may bypass standard signature-based defenses before they establish persistence or exfiltrate sensitive data.

IOC Summary

Malware Family: Unknown malware Total IOCs: 11 IOC Types: sha256_hash, ip:port, url, domain

KQL: Ip Hunt

// Hunt for network connections to known malicious IPs
// Source: ThreatFox - Unknown malware
let malicious_ips = dynamic(["82.38.171.235", "72.5.43.195"]);
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(["82.38.171.235", "72.5.43.195"]);
DeviceNetworkEvents
| where RemoteIP in (malicious_ips)
| project Timestamp, DeviceName, RemoteIP, RemotePort, InitiatingProcessFileName, ActionType
| order by Timestamp desc

KQL: Domain Hunt

// Hunt for DNS queries to known malicious domains
// Source: ThreatFox - Unknown malware
let malicious_domains = dynamic(["auth-code-verif.beer", "maloke.pro", "privatetoken.app"]);
DnsEvents
| where Name has_any (malicious_domains)
| project TimeGenerated, Computer, Name, IPAddresses, QueryType
| order by TimeGenerated desc

KQL: Url Hunt

// Hunt for access to known malicious URLs
// Source: ThreatFox - Unknown malware
let malicious_urls = dynamic(["https://maloke.pro/", "https://productionai-shop.pages.dev/recaptcha-verify", "https://pbhwzixj.boro1.bet/4f9a7c78-781f-4987-9e83-e804fb9a98e2/gc.key", "https://watersolutionsfl.com/", "https://marjdl.pro/"]);
UrlClickEvents
| where Url has_any (malicious_urls)
| project Timestamp, AccountUpn, Url, ActionType, IsClickedThrough
| order by Timestamp desc

KQL: Hash Hunt

// Hunt for files matching known malicious hashes
// Source: ThreatFox - Unknown malware
let malicious_hashes = dynamic(["04dcae7c2f31870f4a59ed6faec513a5e252491d911ae9e62b9c3026ccf598cd"]);
DeviceFileEvents
| where SHA256 in (malicious_hashes) or SHA1 in (malicious_hashes) or MD5 in (malicious_hashes)
| project Timestamp, DeviceName, FileName, FolderPath, SHA256, InitiatingProcessFileName
| order by Timestamp desc

Required Data Sources

References

• ThreatFox — Unknown malware

False Positive Guidance

Here are specific false positive scenarios for the ThreatFox: Unknown malware IOCs detection rule, tailored for an enterprise environment:

• Enterprise Endpoint Protection Scans and Updates

  • Scenario: The organization’s endpoint protection suite (e.g., CrowdStrike Falcon, SentinelOne, or Microsoft Defender for Endpoint) performs scheduled signature updates or deep system scans. These processes often generate new temporary files, DLLs, or executable artifacts in the %TEMP% directory that match generic “unknown” IOCs before being fully whitelisted by the local engine.
  • Suggested Filter: Exclude file paths containing vendor-specific update directories (e.g., C:\ProgramData\Microsoft\Windows Defender\Updates) and filter out processes with known publisher hashes for the EDR vendor’s service executables.

• Automated Patch Management Deployments

  • Scenario: Scheduled patch management tools like Ivanti, ManageEngine Desktop Central, or WSUS (Windows Server Update Services) deploy application patches to workstations. During the installation phase, these tools extract installer packages and create temporary execution contexts that may trigger IOCs associated with unknown file hashes or network connections to update servers not yet in the ThreatFox baseline.
  • Suggested Filter: Create an exclusion for processes running under the context of patch management services (e.g., IvantiAgent.exe, WSUSClient.exe) and whitelist specific destination IP ranges used by the organization’s internal patch repository servers.

• IT Administration Script Execution

  • Scenario: System administrators run PowerShell or Python scripts via Task Scheduler to perform routine maintenance, such as log rotation, user provisioning, or configuration backups. These custom scripts often invoke external tools (like 7-Zip, Git, or curl) that generate network traffic and file system changes matching the “unknown malware”