Aspxor

Overview

Aspxor (classified in antivirus detection telemetry under designations including Trojan:Win32/Aspxor, Trojan.Win32.Aspxor, and Win32/Aspxor) is a multi-stage trojan engineered to disguise itself as legitimate software, execute unauthorized commands, and coordinate with external command-and-control infrastructure. Disseminated across enterprise networks and consumer workstations via social engineering, phishing attachments, malicious drive-by downloads, or weaponized software cracks, Aspxor executes an initial reconnaissance phase upon system ingress. The binary evaluates host privileges, detects active hypervisors and sandbox environments to evade behavioral analysis, and establishes resilient autostart persistence by configuring registry keys under HKCU\Software\Microsoft\Windows\CurrentVersion\Run or registering background Windows services. Operational mechanics characteristic of this family include deceptive executable masquerading, registry run key autostart, system telemetry gathering, and remote C2 beaconing. Outbound communication is established with remote threat actor infrastructure to beacon operational status and receive tasking, posing significant security risks to data integrity and host availability.

Known aliases

Threat reports may refer to this family under multiple names:

• Trojan:Win32/Aspxor
• Trojan.Win32.Aspxor
• Win32/Aspxor

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to our technical analysis hubs and the official MITRE ATT&CK framework:

Tactical Mitigations

Based on the techniques used by this family, consider the following defensive strategies:

• T1071.001: Implement web filtering and SSL/TLS inspection to detect malicious command and control (C2) traffic hiding in HTTP/HTTPS.

MITRE D3FEND™ Defensive Countermeasures

Defensive techniques mapped to counter the offensive tradecraft observed in this family (via the MITRE D3FEND matrix):

Tiered Detection Rules (Cisco CAIRN Model)

Modern threat detection requires multi-layered rule engineering. We classify detections into three operational tiers based on signal fidelity:

rule MALWARE_WIN_ASPXOR_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Aspxor"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "aspxor" ascii wide nocase
        $s2 = "trojan:win32/aspxor" ascii wide nocase
        $s3 = "trojan.win32.aspxor" ascii wide nocase
        $s4 = "win32/aspxor" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Aspxor (Trojan) Execution & Triage
id: ba47b9e3-9816-5e63-9e17-02528cf22084
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Aspxor malware family. Detects suspicious execution from temporary user
  directories with hidden window flags and background transfer utilities.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/aspxor
- https://malware-families-catalog.systemhelpdesk.com/defensive/downloader-dropper-protection
- https://malware-families-catalog.systemhelpdesk.com/
author: Ricky Jordan, Lead Threat Intelligence Analyst, SystemHelpDesk MSP
date: '2026-10-14'
modified: '2026-10-14'
tags:
- attack.trojan
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1059_003
- attack.t1027
- attack.t1547_001
- attack.t1071_001
- attack.t1105
logsource:
  category: process_creation
  product: windows
detection:
  selection_process:
    Image|endswith:
    - \cmd.exe
    - \powershell.exe
    - \cscript.exe
    - \wscript.exe
    CommandLine|contains:
    - AppData\Local\Temp
    - -WindowStyle Hidden
    - /e:jscript
    - bitsadmin /transfer
  condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: medium

rule MALWARE_WIN_ASPXOR_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Aspxor tradecraft"
        tier = "T3 - Attribution Fingerprint"
        confidence = "High (Confirmed Family Signature)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        // Core family identifier & heuristic payload signatures
        $attrib_str = "aspxor" ascii wide nocase
        $pe_magic = "MZ" ascii
        $net_marker = "http" ascii nocase
    condition:
        uint16(0) == 0x5a4d and ($attrib_str and $net_marker) and filesize < 15MB
}

Containment & Response Steps

Ordered checklist for responders. Adapt to your environment and engage professional support for active incidents.

1. Immediately block outbound TCP Port 25 (SMTP) at the firewall for all standard user workstations to halt the spam blast and protect the corporate IP reputation.
2. Isolate the endpoint to sever the C2 connection and prevent it from downloading further spam templates or secondary payloads.
3. Due to the advanced rootkit capabilities, do not rely on standard antivirus removal; perform a bare-metal wipe and reimage of the infected machine.
4. Monitor public spam blacklists (e.g., MXToolbox) to ensure the corporate IP address has not been blacklisted, and initiate delisting procedures if necessary.

What to Avoid

Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.

1. Do not assume the endpoint is clean just because a standard antivirus scan comes back negative; Aspxor's rootkit hides its presence from user-mode APIs.
2. Avoid ignoring the incident; allowing a spambot to operate will quickly result in the company's legitimate emails being rejected by clients and partners.

References & External Analysis

• Microsoft Defender Threat Encyclopedia - Trojan:Win32/Aspxor
• Kaspersky Threat Intelligence - Trojan.Win32.Aspxor
• MITRE ATT&CK - Enterprise Techniques
• Search "aspxor" on VirusTotal (External Analysis)
• Search "aspxor" on Any.Run (Sandbox Sandbox)
• Search "aspxor" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Trojan)

Explore other documented threats in the same operational category:

• Transmit
• Gampass
• Lotoor
• Zombierat
• Regger
• Adanti
• Game
• Separ

Machine-readable

Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/api/aspxor.json

Ecosystem & Interactive Environments

This profile is part of the Malware Families Catalog, a public dataset of 2,899 malware families. The catalog is also published across our ecosystem: Hugging Face, Kaggle, Zenodo, Replit, StackBlitz, CodeSandbox, and CodePen.