user@threatcheck.sh ~ threat-analysis
bash
$ analyze-threat Trojan:Win64/Shelm.M!MTB
Trojan:Win64/Shelm.M!MTB - Windows Defender threat signature analysis

Trojan:Win64/Shelm.M!MTB - Windows Defender Threat Analysis

$ cat analysis.txt
=== THREAT ANALYSIS REPORT ===
Threat Name: Trojan:Win64/Shelm.M!MTB
Classification:
Type:Trojan
Platform:Win64
Family:Shelm
Detection Type:Concrete
Known malware family with identified signatures
Variant:M
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 - Appears legitimate but performs malicious actions for 64-bit Windows platform, family Shelm

Summary:

Trojan:Win64/Shelm.M!MTB is a concrete detection of a malicious program from the Shelm family, identified by Windows Defender using machine learning behavioral analysis. This Trojan, likely implemented as a DLL (indicated by DllInstall, DllMain, DllRegisterServer exports), is designed to execute malicious code, establish persistence, or serve as a component in a larger attack. The presence of 'jnnfcoy.cpl' suggests it might masquerade as a Control Panel item for execution or deception.

Severity:
High
VDM Static Detection:
Relevant strings associated with this threat:
 - yxsohezazveqzwx.dll (PEHSTR_EXT)
 - DllInstall (PEHSTR_EXT)
 - DllMain (PEHSTR_EXT)
 - DllRegisterServer (PEHSTR_EXT)
 - DllUnregisterServer (PEHSTR_EXT)
 - jnnfcoy.cpl (PEHSTR_EXT)
 - NimMain (PEHSTR_EXT)
YARA Rule:
rule Trojan_Win64_Shelm_M_2147907802_0
{
    meta:
        author = "threatcheck.sh"
        detection_name = "Trojan:Win64/Shelm.M!MTB"
        threat_id = "2147907802"
        type = "Trojan"
        platform = "Win64: Windows 64-bit platform"
        family = "Shelm"
        severity = "Critical"
        info = "MTB: Microsoft Threat Behavior"
        signature_type = "SIGNATURE_TYPE_PEHSTR_EXT"
        threshold = "4"
        strings_accuracy = "Low"
    strings:
        $x_2_1 = {8b 37 41 8b de 49 03 f1 48 8d 7f ?? 0f be 0e 48 ff c6 c1 cb ?? 03 d9 84 c9}  //weight: 2, accuracy: Low
        $x_2_2 = {41 8d 0c 30 45 03 ?? 80 34 ?? ?? 44 3b c0}  //weight: 2, accuracy: Low
    condition:
        (filesize < 20MB) and
        (all of ($x*))
}
Known malware which is associated with this threat:
Filename: VPN客户端安全补丁.exe
e06d884fe36697b80ca12374142c9d0755f16a1bd7e5ec4e141c432827b64b24
27/12/2025
→VirusTotal↓Download Sample
Remediation Steps:
Immediately isolate the affected system to prevent further compromise. Perform a full system scan with updated antivirus definitions to remove the detected threat. Investigate for persistence mechanisms (e.g., startup entries, scheduled tasks) and any signs of lateral movement or data exfiltration on the network.
=== END REPORT ===
$ reanalyze-threat
This analysis was last updated on 27/12/2025. Do you want to analyze it again?
$ ls available-commands/
→ cd /home
user@threatcheck.sh:~$ ▊