The detection identifies potential malicious activity associated with the file iastor32.exe, which is linked to the Sphinx Moth threat group. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify and mitigate early-stage adversarial actions that may evade traditional detection methods.
YARA Rule
rule Sphinx_Moth_iastor32
{
meta:
description = "sphinx moth threat group file iastor32.exe"
author = "Kudelski Security - Nagravision SA"
reference = "www.kudelskisecurity.com"
date = "2015-08-06"
strings:
$s0 = "MIIEpQIBAAKCAQEA4lSvv/W1Mkz38Q3z+EzJBZRANzKrlxeE6/UXWL67YtokF2nN" fullword ascii /* private key */
$s1 = "iAeS3CCA4wli6+9CIgX8SAiXd5OezHvI1jza61z/flsqcC1IP//gJVt16nRx3s9z" fullword ascii /* private key */
condition:
uint16(0) == 0x5a4d and filesize < 2000KB and all of them
}
This YARA rule can be deployed in the following contexts:
This rule contains 2 string patterns in its detection logic.
Scenario: Scheduled System Maintenance Task
Description: The iastor32.exe process is executed as part of a legitimate scheduled task for disk maintenance or firmware updates.
Filter/Exclusion: Check for CommandLine containing /C or /S flags, or filter by ProcessName matching iastor32.exe and ParentProcess being schtasks.exe or taskhost.exe.
Scenario: Windows Update or Driver Installation
Description: The file is executed during a Windows Update or driver installation process, which may involve running iastor32.exe to update storage drivers.
Filter/Exclusion: Filter by ParentProcess being wuauclt.exe or setup.exe, or check for CommandLine containing update or install.
Scenario: Third-Party Storage Management Tool
Description: A legitimate third-party storage management tool (e.g., Dell Storage Manager, HP Storage Manager) uses iastor32.exe for hardware diagnostics or configuration.
Filter/Exclusion: Filter by ProcessName matching iastor32.exe and ParentProcess being a known management tool (e.g., DellStorageManager.exe, hpstorsv.exe).
Scenario: Administrative Script or PowerShell Job
Description: An admin script or PowerShell job is executed that calls iastor32.exe as part of a system configuration or cleanup task.
Filter/Exclusion: Filter by ParentProcess being powershell.exe or cmd.exe, and check for CommandLine containing script or job in the command line.
Scenario: Antivirus or Endpoint Protection Scan
Description: An endpoint protection tool (e