ThreatFox: SmokeLoader IOCs

Hunt Hypothesis

The ThreatFox: SmokeLoader IOCs rule detects potential command and control communication associated with the SmokeLoader malware, which is commonly used for initial access and persistence. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify and mitigate early-stage compromises before lateral movement and data exfiltration occur.

IOC Summary

Malware Family: SmokeLoader Total IOCs: 2 IOC Types: url

KQL: Url Hunt

// Hunt for access to known malicious URLs
// Source: ThreatFox - SmokeLoader
let malicious_urls = dynamic(["https://spasopro.at/index.php", "http://spasopro.at/index.php"]);
UrlClickEvents
| where Url has_any (malicious_urls)
| project Timestamp, AccountUpn, Url, ActionType, IsClickedThrough
| order by Timestamp desc

Required Data Sources

References

• ThreatFox — SmokeLoader

False Positive Guidance

• Scenario: Scheduled System Maintenance Task
  Description: A legitimate scheduled task using schtasks.exe to perform system maintenance (e.g., disk cleanup, log rotation) may trigger the rule if the task name or command line matches known SmokeLoader IOCs.
  Filter/Exclusion: process.parent_process_name == "schtasks.exe" or process.command_line contains "schtasks.exe /create"

• Scenario: Log Management Tool Configuration
  Description: A log management tool like Splunk or ELK Stack may generate alerts or logs that include IP addresses or hashes associated with SmokeLoader, especially during configuration or data ingestion.
  Filter/Exclusion: process.name contains "splunkd.exe" or process.name contains "logstash"

• Scenario: Windows Update or Patching Job
  Description: A Windows Update or patching job using PowerShell or Group Policy may include scripts or commands that resemble SmokeLoader IOCs due to similar syntax or command structures.
  Filter/Exclusion: process.name contains "wuauclt.exe" or process.name contains "gpupdate.exe"

• Scenario: Database Backup Job
  Description: A database backup job using SQL Server Agent or MySQL Workbench may involve scripts or commands that include paths or hashes similar to those associated with SmokeLoader.
  Filter/Exclusion: process.name contains "sqlservr.exe" or process.name contains "mysqld.exe"

• Scenario: Security Software Scan
  Description: A security software like Malwarebytes or Bitdefender may generate alerts or logs that include IOCs from known malware, including those associated with SmokeLoader, during a scan.
  Filter/Exclusion: `process.name contains “mbam.exe