Cidox

Overview

Executive Summary

Infection Vector and Technical Capabilities

• Bootkit Persistence (MBR/VBR Infection): Unlike standard malware that hides in the registry, Cidox targets the fundamental boot process of the hard drive. It overwrites the Master Boot Record (MBR) or the Volume Boot Record (VBR). This guarantees that the malicious code executes *before* the Windows kernel or any antivirus software even loads into memory.
• Kernel-Mode Rootkit: Once the OS boots, the bootkit injects a malicious driver into the Windows kernel space (Ring 0). This rootkit intercepts system calls (API hooking), allowing Cidox to completely hide its files, registry keys, and active network connections from the user and security software.
• Payload Delivery (Banking Fraud): With absolute stealth achieved, the Cidox framework silently downloads and executes its primary payload—usually a sophisticated banking trojan designed to perform web injection and steal financial credentials.

Threat Assessment

Incident Response and Remediation

• Ineffectiveness of Standard AV: Traditional antivirus scans running within the infected OS cannot be trusted, as the kernel-mode rootkit will actively lie to the AV scanner about the state of the hard drive.
• Offline Eradication (Bare-Metal): The only reliable method to eradicate Cidox is a complete bare-metal wipe. The hard drive must be completely reformatted (including wiping the MBR/GPT partition tables) using offline media, and the operating system must be reinstalled from a known-secure image.
• Secure Boot (Prevention): The rise of UEFI and Microsoft's "Secure Boot" feature (which cryptographically verifies the bootloader before execution) has largely rendered MBR/VBR bootkits like Cidox obsolete on modern hardware. Ensure Secure Boot is strictly enabled in the BIOS/UEFI settings for all corporate endpoints.

Known aliases

Threat reports may refer to this family under multiple names:

• Rootkit.Cidox
• Trojan.Rovnix
• Bootkit.Win32.Cidox

MITRE ATT&CK Techniques

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

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_CIDOX_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Cidox"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "cidox" ascii wide nocase
        $s2 = "rootkit.cidox" ascii wide nocase
        $s3 = "trojan.rovnix" ascii wide nocase
        $s4 = "bootkit.win32.cidox" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Cidox (Trojan) Execution & Triage
id: 686d66b3-e6c4-507d-baaf-fa084c08f704
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Cidox 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/cidox
- 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.t1542_003
- attack.t1014
- attack.t1055
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_CIDOX_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Cidox 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 = "cidox" 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. Sever network connectivity for the flagged endpoint to terminate persistent command-and-control (C2) communication channels and stop Cidox from retrieving secondary stage payloads.
2. Capture process memory triage to detect and terminate malicious threads injected by Cidox into legitimate system processes such as explorer.exe or svchost.exe.
3. Audit Windows Registry Run keys (HKCU\Software\Microsoft\Windows\CurrentVersion\Run) and Task Scheduler entries to locate and purge Cidox persistence hooks.
4. Deploy updated enterprise EDR detection signatures and conduct an out-of-band endpoint scan to isolate dropped binaries and staged payloads.
5. Rotate all credentials, domain user passwords, and session cookies active on the system during the Cidox execution timeframe.

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 incident is resolved simply because an antivirus tool removed the initial Cidox dropper; always verify that secondary payloads and persistence hooks have been eradicated.
2. Avoid logging in with Domain Admin or privileged credentials on a machine suspected of running Cidox until memory triage is complete.
3. Do not delay host isolation; automated lateral movement and credential dumping can occur within minutes of initial execution.

References & External Analysis

• Search "cidox" on VirusTotal (External Analysis)
• Search "cidox" on Any.Run (Sandbox Sandbox)
• Search "cidox" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Trojan)

Explore other documented threats in the same operational category:

• Sneepy
• Pwszbot
• Gameserver
• Indigorose
• Autoitscript
• Neutrinopos
• Polip
• Separ

Machine-readable

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