Upatre

Overview

Upatre is a notoriously lightweight, high-volume downloader first identified in mid-2013 that served as the initial spearhead for some of the most catastrophic cybercrime operations in history, including GameOver Zeus (GOZ), Dyre (Dyreza), and CryptoLocker. Written in C/C++, Upatre was engineered with a hyper-minimalist footprint (often smaller than 35 KB) specifically optimized to slip past perimeter email security gateways, antivirus heuristics, and sandboxes. Upatre was predominantly disseminated via massive automated phishing blitzes disguised as official communications—such as bank wire confirmations, tax documents, internal office faxes, and package delivery notifications. These emails carried weaponized ZIP archives or PDFs embedding executable payloads disguised with double extensions (e.g. Invoice.pdf.exe). Upon initial execution, Upatre performs process injection into trusted operating system processes like explorer.exe, svchost.exe, or notepad.exe. It then initiates encrypted SSL/TLS or raw TCP connections directly to compromised web servers or Tor gateways, downloads a second-stage encrypted binary payload, decrypts it using proprietary multi-byte XOR routines, and spawns the secondary malware before terminating its own process to minimize on-disk forensic artifacts.

Known aliases

Threat reports may refer to this family under multiple names:

• Upatre
• Downloader.Upatre

Threat Actor Attribution

Attribution is probabilistic, not a science. Each link below states its confidence level and the evidence behind it.

• Russian-speaking Cybercrime Syndicates (GameOver Zeus & Dyre Operators) High confidence
  Basis: Closely affiliated with the operators of GameOver Zeus (Evgeniy Bogachev syndicate) and the Dyre banking gang, serving as their premier first-stage delivery mechanism from 2013 to 2016. [source]

Family Pedigree & Lineage

Malware authors regularly fork and iterate upon existing codebases. Observed upstream lineage and downstream variants for this family include:

Known Derivatives & Downstream Variants: Upatre Ssl Variant · Upatre Tor Gateway Variant

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:

• T1105: Implement network intrusion detection systems (NIDS) and host-based firewalls to block unauthorized inbound or outbound file transfers.
• T1566.001: Scan email attachments for malicious macros, scripts, or suspicious archive files.

MITRE D3FEND™ Defensive Countermeasures

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

Exploited Vulnerabilities (CVEs)

This malware family is documented weaponizing the following common vulnerabilities and exposures:

• CVE-2014-1761 — In-depth exploitation analysis and catalog intelligence (NIST NVD ↗).
• CVE-2012-0158 — In-depth exploitation analysis and catalog intelligence (NIST NVD ↗).

Command & Control (C2) and Network Profile

How this family talks to its operators. C2 traffic can often identify a family even when its code and configuration are hard to analyse. Ports and patterns are historical and change between campaigns, so use them as hunting leads rather than block-only rules.

Network detection ideas

• Inspect perimeter web proxy logs for newly observed IP connections downloading obfuscated binaries
• Block inbound emails containing executable files disguised with double extensions inside archive formats
• Detect injection of network socket code from non-network administrative binaries like notepad.exe

Sources: CISA / US-CERT Alert TA14-153A: GameOver Zeus and Upatre, FBI GameOver Zeus & Upatre Takedown Announcement

Indicators of Compromise

Public indicators drawn from CISA advisories and vendor reporting. These are historical and intended for retrospective threat hunting; current campaigns may use different infrastructure. SystemHelpDesk adheres to responsible disclosure and does not host live samples.

File hashes (SHA-256, sample)

Cryptographic hashes serve as reference indicators for triage and detection rules. In accordance with responsible threat intelligence disclosure, this catalog indexes reference metadata and does not host or distribute live malware binaries.

• 6a22f3e098867568e64c23ba38fe1cb34948a31e1dbfa3e2e8b61c82823624e5
• 9e144a0b272fca364a2c1409bf94f923cebfa1202ec0ef8c36294eb8e390c50d

Delivery vectors

• Mass-scale phishing campaigns with subject lines referencing wire transfers, unpaid invoices, or shipping updates
• Compressed ZIP attachments containing double-extension executable payloads (e.g., Doc_7281.pdf.exe)

Persistence mechanisms

• Temporary process hollowing into explorer.exe or svchost.exe
• Registry Run keys in HKCU\Software\Microsoft\Windows\CurrentVersion\Run pointing to downloaded payloads

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_UPATRE_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Upatre"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "upatre" ascii wide nocase
        $s2 = "upatre" ascii wide nocase
        $s3 = "downloader.upatre" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Upatre (Downloader) Execution & Triage
id: a0d93697-2ad6-58dc-8b2f-499aa8d96fe1
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Upatre 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/upatre
- https://malware-families-catalog.systemhelpdesk.com/defensive/ransomware-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.downloader
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1566_001
- attack.t1055
- attack.t1105
- attack.t1573_001
- attack.t1027
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_UPATRE_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Upatre 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 = "upatre" 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 isolate the affected endpoint from the corporate LAN.
2. Identify what secondary payloads were downloaded (e.g. Dyre, GameOver Zeus, CryptoLocker) before Upatre terminated.
3. Inspect outbound proxy logs to block the C2 IP addresses from which payloads were fetched.
4. Verify Active Directory user accounts for unauthorized credential access or fraudulent wire transfers.
5. Re-image the endpoint if secondary payloads executed successfully.

What to Avoid

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

1. Do not focus solely on removing the Upatre binary; Upatre almost always downloads a secondary, much more destructive banking trojan or ransomware locker.
2. Do not allow users to execute attachments from unverified external emails without sandboxing.

References & External Analysis

• Malpedia (Fraunhofer FKIE): Upatre (win.upatre)
• CISA Advisory: CISA Alert TA14-153A (GameOver Zeus and Upatre Remediation)
• Search "upatre" on VirusTotal (External Analysis)
• Search "upatre" on Any.Run (Sandbox Sandbox)
• Search "upatre" on MalwareBazaar (Malware Samples)

North American Authority Advisory (CISA / NIST)

The Cybersecurity and Infrastructure Security Agency (CISA) has published an official US federal advisory on this family, which can be mapped to NIST Cybersecurity Framework (CSF) incident response controls: CISA Alert TA14-153A (GameOver Zeus and Upatre Remediation) ↗

Frequently Asked Questions

Related Threats (Category: Downloader)

Explore other documented threats in the same operational category:

• Nymeria
• Rubinurd
• Tempedreve
• Reconyc
• Bancteian
• Tinyloader
• Nymaim
• Dlhelper

Machine-readable

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