user@threatcheck.sh ~ threat-analysis
bash
$ analyze-threat TrojanDownloader:VBS/AsyncRAT.NS!MTB
TrojanDownloader:VBS/AsyncRAT.NS!MTB - Windows Defender threat signature analysis

TrojanDownloader:VBS/AsyncRAT.NS!MTB - Windows Defender Threat Analysis

$ cat analysis.txt
=== THREAT ANALYSIS REPORT ===
Threat Name: TrojanDownloader:VBS/AsyncRAT.NS!MTB
Classification:
Type:TrojanDownloader
Platform:VBS
Family:AsyncRAT
Detection Type:Concrete
Known malware family with identified signatures
Variant:NS
Specific signature variant within the malware family
Suffix:!MTB
Detected via machine learning and behavioral analysis
Detection Method:Behavioral
Confidence:Very High
False-Positive Risk:Low

Concrete signature match: Trojan Downloader - Downloads additional malware for VBScript platform, family AsyncRAT

Summary:

This threat is a VBScript downloader that installs the AsyncRAT remote access trojan, giving an attacker full control over the system. It uses multiple built-in Windows tools (LOLBAS) like PowerShell, BITS, and Scheduled Tasks to download its payload, execute code, and establish persistence while evading detection.

Severity:
High
VDM Static Detection:
Relevant strings associated with this threat:
 - Advanced_Calculator.Properties.Resources.resources (PEHSTR_EXT)
 - kbakc.exe (PEHSTR_EXT)
Relevant strings associated with this threat:
 - !#HSTR:StringCodeForMshta.A!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForHooking.C!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForHooking.D!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForHooking.L!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForHooking.O!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForRegsvr32.A!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForRundll32.A!pli (PEHSTR_EXT)
 - rundll32 (PEHSTR_EXT)
 - !#HSTR:StringCodeForBITSJobs.A!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForPowerShell.G!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForScheduledTask.A!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForDataEncoding.D!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForHooking.J!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForHooking.K!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForRemoteFileCopy.B!pli (PEHSTR_EXT)
 - !#HSTR:ExecutionGuardrails (PEHSTR_EXT)
 - !#HSTR:StringCodeForFileDeletion.A!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForHooking.M!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForNetshHelperDLL.A!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForRemoteServices.A!pli (PEHSTR_EXT)
No specific strings found for this threat
YARA Rule:
rule Trojan_MSIL_AsyncRAT_NSY_2147852198_0
{
    meta:
        author = "threatcheck.sh"
        detection_name = "Trojan:MSIL/AsyncRAT.NSY!MTB"
        threat_id = "2147852198"
        type = "Trojan"
        platform = "MSIL: .NET intermediate language scripts"
        family = "AsyncRAT"
        severity = "Critical"
        info = "MTB: Microsoft Threat Behavior"
        signature_type = "SIGNATURE_TYPE_PEHSTR_EXT"
        threshold = "6"
        strings_accuracy = "Low"
    strings:
        $x_5_1 = {8d 17 00 00 01 25 16 72 ?? ?? 00 70 a2 25 17 7e ?? ?? 00 0a a2 25 18 09 a2 25 19 17 8c ?? ?? 00 01 a2 13 04 14 13 05 07 28 ?? ?? 00 0a 72 ?? ?? 00 70 6f ?? ?? 00 0a 72 ?? ?? 00 70 20 ?? ?? 00 00 14 11 05 11 04 74 ?? ?? 00 1b 6f ?? ?? 00 0a}  //weight: 5, accuracy: Low
        $x_1_2 = "Advanced_Calculator.Properties.Resources.resources" ascii //weight: 1
    condition:
        (filesize < 20MB) and
        (all of ($x*))
}
Known malware which is associated with this threat:
cdf18dce59da13a347c6d2d60a0bf6190228b46e595863308769a1cb34ca5fd0
07/11/2025
→VirusTotal↓Download Sample
Remediation Steps:
Immediately isolate the endpoint from the network. Run a full antivirus scan to remove detected files. Manually inspect and remove persistence mechanisms like suspicious Scheduled Tasks. Due to the RAT payload, assume full system compromise: change all associated user passwords and consider reimaging the device.
=== END REPORT ===
$ reanalyze-threat
This analysis was last updated on 08/11/2025. Do you want to analyze it again?
$ ls available-commands/
→ cd /home
user@threatcheck.sh:~$ ▊