Backdoor:Linux/Mirai.FX!MTB

user@threatcheck.sh ~ threat-analysis

bash

$ analyze-threat Backdoor:Linux/Mirai.FX!MTB

Backdoor:Linux/Mirai.FX!MTB - Windows Defender threat signature analysis

$ cat analysis.txt

=== THREAT ANALYSIS REPORT ===

Threat Name: Backdoor:Linux/Mirai.FX!MTB

Classification:

Type:Backdoor

Platform:Linux

Family:Mirai

Detection Type:Concrete

Known malware family with identified signatures

Variant:FX

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 Linux platform, family Mirai

Summary:

This detection identifies a specific variant (FX) of the Mirai botnet backdoor targeting Linux systems. This malware gains unauthorized access to the infected machine, likely incorporating it into a botnet for Distributed Denial of Service (DDoS) attacks or other malicious activities.

Severity:

Critical

VDM Static Detection:

No specific strings found for this threat

YARA Rule:

rule Backdoor_Linux_Mirai_FX_2147906252_0
{
    meta:
        author = "threatcheck.sh"
        detection_name = "Backdoor:Linux/Mirai.FX!MTB"
        threat_id = "2147906252"
        type = "Backdoor"
        platform = "Linux: Linux platform"
        family = "Mirai"
        severity = "Critical"
        info = "MTB: Microsoft Threat Behavior"
        signature_type = "SIGNATURE_TYPE_ELFHSTR_EXT"
        threshold = "2"
        strings_accuracy = "Low"
    strings:
        $x_1_1 = {05 00 a0 e1 7c ff ff eb 07 00 a0 e1 7a ff ff eb 38 10 9f e5 04 20 a0 e3 01 00 a0 e3 8b ff ff eb 05 00 a0 e3 70 ff ff eb 94 d0 8d e2 f0 81 bd e8}  //weight: 1, accuracy: High
        $x_1_2 = {8a ff ff 1b 93 30 dd e5 04 44 83 e1 7c 30 9f e5 03 00 54 e1 f3 ?? ?? ?? 0d 10 a0 e1 80 20 a0 e3 05 00 a0 e1 a1 ff ff eb 00 20 50 e2 0d 40 a0 e1 0d 10 a0 e1}  //weight: 1, accuracy: Low
    condition:
        (filesize < 20MB) and
        (all of ($x*))
}

Known malware which is associated with this threat:

Filename: dlr.arm

f89569a00e3116bf0f86287951d9d3759878c5fd6e4c0c9e9c8e43324be82b1c

15/01/2026

→VirusTotal ↓Download Sample

Filename: dlr.arm5

e79751620d99c5e7bcf429faded8d6cd9e13d9c897aa8128c5224eb4e006a5f2

15/01/2026

→VirusTotal ↓Download Sample

Remediation Steps:

Immediately isolate the affected Linux system, perform a comprehensive malware scan and removal, and apply all available system and firmware updates. Implement strong, unique passwords for all accounts and enforce strict network segmentation with appropriate firewall rules to prevent further compromise.

=== END REPORT ===

$ reanalyze-threat

This analysis was last updated on 15/01/2026. Do you want to analyze it again?

$ ls available-commands/

→ cd /home

user@threatcheck.sh:~$ ▊

Backdoor:Linux/Mirai.FX!MTB - Windows Defender Threat Analysis