ThreatFox: StrelaStealer IOCs

Hunt Hypothesis

The ThreatFox: StrelaStealer IOCs rule detects potential credential-stealing activity associated with the StrelaStealer malware, which exfiltrates sensitive data from compromised systems. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify and mitigate advanced threats before significant data loss occurs.

IOC Summary

Malware Family: StrelaStealer Total IOCs: 6 IOC Types: domain

KQL: Domain Hunt

// Hunt for DNS queries to known malicious domains
// Source: ThreatFox - StrelaStealer
let malicious_domains = dynamic(["healwithcolors.com", "fmt.co.id", "extinvit.es", "englishnews.eu", "ekonomimanajemen.com", "ehsanamidian.com"]);
DnsEvents
| where Name has_any (malicious_domains)
| project TimeGenerated, Computer, Name, IPAddresses, QueryType
| order by TimeGenerated desc

Required Data Sources

References

• ThreatFox — StrelaStealer

False Positive Guidance

• Scenario: Legitimate scheduled job using PowerShell for system monitoring
  Description: A system administrator schedules a PowerShell script using schtasks to monitor system performance and log events. The script may use Invoke-Command or Get-EventLog, which could trigger the rule due to PowerShell activity.
  Filter/Exclusion: ProcessName != "powershell.exe" OR CommandLine NOT LIKE "*Invoke-Command*" AND CommandLine NOT LIKE "*Get-EventLog*"

• Scenario: Admin using Process Explorer to troubleshoot a service
  Description: A system administrator uses Sysinternals’ Process Explorer to investigate a suspicious service. The tool may trigger the rule due to process enumeration or memory inspection activities.
  Filter/Exclusion: ProcessName != "procexp.exe" OR CommandLine NOT LIKE "*-e*" AND CommandLine NOT LIKE "*-m*"

• Scenario: Regular log collection using LogParser
  Description: A security team uses LogParser (from the Windows Server Resource Kit) to collect and analyze event logs. The tool may trigger the rule due to its interaction with the Windows Event Log API.
  Filter/Exclusion: `ProcessName != “logparser.exe” OR CommandLine NOT LIKE “-i event”

• Scenario: Deployment of a legitimate configuration management tool
  Description: A DevOps engineer deploys a configuration management tool like Ansible or Chef that uses PowerShell or other scripting to configure systems. The script execution may trigger the rule.
  Filter/Exclusion: ProcessName NOT IN ("ansible.exe", "chef-client.exe") OR CommandLine NOT LIKE "*-e*" AND CommandLine NOT LIKE "*-t*"

• Scenario: User running a legitimate remote desktop session
  Description: A user connects to a remote server using mstsc.exe (Remote Desktop Connection