Uploader

Category: trojan · Aliases: Trojan.Uploader, HackTool.Uploader, Exfiltration.Tool · Sample count (EMBER 2018): 1 · Enrichment: insufficient_information · Updated: 2026-07-01T17:23:59Z

Category: TrojanActor: Unknown / CybercriminalIndustry: Global / OpportunisticMotivation: Opportunistic

Overview

Executive Summary

"Uploader" is a classification for a specialized class of Trojan or HackTool primarily designed for data exfiltration. Unlike "Downloaders" which pull malware onto a system, an Uploader's sole objective is to securely package and transmit sensitive data (such as stolen credentials, proprietary documents, or keylogger logs) from the compromised internal network out to an external server controlled by the attacker.

Infection Vector and Technical Capabilities

Uploaders are rarely the initial vector of compromise. They are typically dropped and executed by a primary Trojan (like an Info-stealer) or manually deployed by a threat actor who has achieved interactive access via lateral movement or compromised VPN credentials. Once executed, the Uploader focuses on stealthy exfiltration:

Data Staging and Archiving: The tool locates a staging directory (often created by a companion info-stealer), compresses the stolen data into an archive (like a password-protected `.zip` or `.rar`), and splits it into smaller chunks to avoid triggering data loss prevention (DLP) alerts based on large file transfers.
Covert Exfiltration: To bypass perimeter firewalls, Uploaders utilize standard, allowed protocols. They frequently upload the staged data via HTTP POST requests, FTP, or increasingly, by misusing legitimate cloud storage APIs (like Google Drive, Dropbox, or OneDrive) to blend the exfiltration with normal corporate web traffic.
Self-Deletion: Once the transfer is successfully acknowledged by the attacker's C2 server, the Uploader will often securely delete the staging archives and its own executable to destroy forensic evidence.

Threat Assessment

The detection of an Uploader in action is a critical, "break-glass" incident. It definitively confirms that the network has been breached, sensitive data has been successfully harvested, and the exfiltration phase of the attack is currently underway.

Incident Response and Remediation

Immediate Network Containment: The absolute highest priority is to sever the connection to the attacker's server. Implement immediate firewall blocks against the destination IP address or cloud service being utilized for exfiltration.
Data Loss Assessment: Security teams must aggressively review proxy logs, firewall traffic, and DNS queries to determine exactly how much data was successfully transmitted before the connection was severed, and identify the contents of the staging directory.
Global Credential Reset and Hunt: Assume a severe breach. Force a global password reset for all Active Directory users and initiate a comprehensive threat hunt to identify the initial point of compromise and the tools used to harvest the data.

Known aliases

Threat reports may refer to this family under multiple names:

MITRE ATT&CK Techniques

This family has been observed using the following ATT&CK techniques: T1041 T1567.002 T1048 T1074.001

Generated Detections (Boilerplate)

These YARA and Sigma rules are auto-generated based on the family name and aliases. They must be heavily tuned before deployment in a production environment.

YARA Rule

rule MALWARE_WIN_UPLOADER {
    meta:
        description = "Detects Uploader (trojan)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "uploader" ascii wide nocase
        $s2 = "trojan.uploader" ascii wide nocase
        $s3 = "hacktool.uploader" ascii wide nocase
        $s4 = "exfiltration.tool" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Uploader Activity
id: 764de9f0293d3b22dc80afe67679fbb3
status: experimental
description: Detects generic indicators of the uploader malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*uploader*"
            - "*trojan.uploader*"
            - "*hacktool.uploader*"
            - "*exfiltration.tool*"
    condition: selection
level: medium

References & External Analysis

Search "uploader" on VirusTotal (External Analysis)

Frequently Asked Questions

How do I remove the Uploader Trojan from Windows?

Manual removal of Uploader is highly discouraged as it may leave persistence mechanisms intact. We recommend disconnecting the device from the internet and utilizing a professional incident response service or enterprise-grade EDR software to conduct a full forensic sweep.

Is Uploader a virus or a Trojan?

Uploader is classified as a Trojan. Unlike traditional viruses that infect files, modern malware like Uploader typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.

What are the main symptoms of a Uploader infection?

Symptoms of Uploader can include unexpected system slowness, unauthorized outbound network traffic to unknown IP addresses, disabled security software, and suspicious background processes running from AppData or Temp directories.

Related Families (Category: trojan)

Explore other malware families in the same category:

Protect Your Network Against Trojans

Want to prevent Uploader and similar threats from compromising your organization? Read our comprehensive defensive guide: Banking Trojan Protection.

Need help with an active incident? Published by the SystemHelpdesk team.

Machine-readable

Get this profile as JSON: https://jordan123234-malware-families-explorer.static.hf.space/api/uploader.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.