The hypothesis is that the detection identifies potential Iron Tiger Malware activity involving a NBDDos Gh0stvariant dropper, which may indicate initial compromise or lateral movement within a network. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify and mitigate early-stage malware infections before they escalate to data exfiltration or system disruption.
YARA Rule
rule IronTiger_NBDDos_Gh0stvariant_dropper
{
meta:
author = "Cyber Safety Solutions, Trend Micro"
description = "Iron Tiger Malware - NBDDos Gh0stvariant Dropper"
reference = "http://goo.gl/T5fSJC"
strings:
$str1 = "This service can't be stoped." nocase wide ascii
$str2 = "Provides support for media palyer" nocase wide ascii
$str4 = "CreaetProcess Error" nocase wide ascii
$bla1 = "Kill You" nocase wide ascii
$bla2 = "%4.2f GB" nocase wide ascii
condition:
uint16(0) == 0x5a4d and ((any of ($str*)) or (all of ($bla*)))
}
This YARA rule can be deployed in the following contexts:
This rule contains 5 string patterns in its detection logic.
Scenario: A system administrator is using PowerShell to execute a scheduled job that deploys a software update.
Filter/Exclusion: Check for ProcessName containing powershell.exe and CommandLine containing -Command with a known update script path.
Scenario: A Windows Task Scheduler job is configured to run a legitimate script that interacts with the Network Block Device (NBD) for backup purposes.
Filter/Exclusion: Filter by ProcessName containing schtasks.exe and CommandLine containing /RUN with a known backup script path.
Scenario: A System Center Configuration Manager (SCCM) agent is performing a software deployment that involves network communication with a remote server.
Filter/Exclusion: Filter by ProcessName containing ccmexec.exe and DestinationIP matching the SCCM server IP address.
Scenario: A Windows Update Agent is downloading and installing updates, which may involve network communication that resembles malicious behavior.
Filter/Exclusion: Filter by ProcessName containing wuauclt.exe and DestinationIP matching Microsoft update servers.
Scenario: A Database Administrator (DBA) is using SQL Server Management Studio (SSMS) to run a maintenance job that connects to a remote SQL server.
Filter/Exclusion: Filter by ProcessName containing ssms.exe and DestinationIP matching the known SQL server IP address.