user@threatcheck.sh ~ threat-analysis
bash
$ analyze-threat Backdoor:MSIL/Crysan.ARA!MTB
Backdoor:MSIL/Crysan.ARA!MTB - Windows Defender threat signature analysis

Backdoor:MSIL/Crysan.ARA!MTB - Windows Defender Threat Analysis

$ cat analysis.txt
=== THREAT ANALYSIS REPORT ===
Threat Name: Backdoor:MSIL/Crysan.ARA!MTB
Classification:
Type:Backdoor
Platform:MSIL
Family:Crysan
Detection Type:Concrete
Known malware family with identified signatures
Variant:ARA
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: Backdoor - Provides unauthorized remote access for .NET (Microsoft Intermediate Language) platform, family Crysan

Summary:

This is a concrete detection of Backdoor:MSIL/Crysan.ARA!MTB, a highly sophisticated .NET backdoor. It exhibits rootkit capabilities, leveraging machine learning behavioral analysis, and uses functions like `GetExecutingAssembly` for dynamic code execution or self-inspection to maintain persistence and evade detection.

Severity:
Critical
VDM Static Detection:
Relevant strings associated with this threat:
 - GetExecutingAssembly (PEHSTR_EXT)
 - gine Shielden v2.4.0.0 (PEHSTR_EXT)
YARA Rule:
rule Backdoor_MSIL_Crysan_ARA_2147914333_0
{
    meta:
        author = "threatcheck.sh"
        detection_name = "Backdoor:MSIL/Crysan.ARA!MTB"
        threat_id = "2147914333"
        type = "Backdoor"
        platform = "MSIL: .NET intermediate language scripts"
        family = "Crysan"
        severity = "Critical"
        info = "MTB: Microsoft Threat Behavior"
        signature_type = "SIGNATURE_TYPE_PEHSTR_EXT"
        threshold = "8"
        strings_accuracy = "High"
    strings:
        $x_2_1 = "%RootKit%" wide //weight: 2
        $x_3_2 = "$4a2f8fb6-1077-469a-9246-736e6afe8da1" ascii //weight: 3
        $x_3_3 = "Client.exe" wide //weight: 3
        $x_1_4 = "GetExecutingAssembly" ascii //weight: 1
        $x_1_5 = "ToArray" ascii //weight: 1
    condition:
        (filesize < 20MB) and
        (
            ((2 of ($x_3_*) and 2 of ($x_1_*))) or
            ((2 of ($x_3_*) and 1 of ($x_2_*))) or
            (all of ($x*))
        )
}
Known malware which is associated with this threat:
Filename: VoiceMod.exe
e4c5a5dd0c918e1735a670b8f7164c3619332083b2074a6f6105303ffe83f70d
10/01/2026
→VirusTotal↓Download Sample
Filename: winws.exe
1565682646b8a4dd630ff2fbc37dd696f55132e9e83a0847e4231c471c76754c
01/01/2026
→VirusTotal↓Download Sample
Remediation Steps:
Immediately isolate any infected systems to prevent further compromise. Perform a full system scan with updated antivirus software to remove the detected malware and any associated components. Investigate and remove persistence mechanisms (e.g., registry run keys, scheduled tasks) and review network logs for suspicious C2 communications. Due to potential rootkit functionality, consider a system re-image for complete eradication.
=== END REPORT ===
$ reanalyze-threat
This analysis was last updated on 01/01/2026. Do you want to analyze it again?
$ ls available-commands/
→ cd /home
user@threatcheck.sh:~$ ▊