Ulysses

Overview

Ulysses (cataloged across security archives as Ulysses RAT, Trojan.Win32.Ulysses, and Backdoor.Win32.Ulysses) is an early 2000s Remote Access Trojan created in Visual Basic and Delphi. Engineered during the classic era of client-server backdoors, Ulysses was designed to provide unauthorized operators with administrative control over compromised Windows 9x, ME, and 2000 workstations. Operating over direct TCP connections, Ulysses configures an autostart entry in the Windows registry Run key, binds to a listening server port, and waits for incoming connections from the operator's client software. Once connected, attackers can browse and exfiltrate files, execute arbitrary command shell instructions, enumerate and kill running processes, capture desktop screenshots, and tamper with system configuration settings.

Known aliases

Threat reports may refer to this family under multiple names:

• Ulysses RAT
• Trojan.Ulysses
• Backdoor.Win32.Ulysses
• Ulysses 1.0
• Backdoor:Win32/Ulysses

Family Pedigree & Lineage

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

Derived From / Upstream Ancestry: Early Win32 Rat Era

Known Derivatives & Downstream Variants: Ulysses 1.0 · Ulysses 1.2 · Ulysses.Gen

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:

• T1059.003: Restrict execution of Windows Command Shell (cmd.exe) and block unauthorized batch scripts.
• T1071.001: Implement web filtering and SSL/TLS inspection to detect malicious command and control (C2) traffic hiding in HTTP/HTTPS.
• T1113: Monitor for frequent or unauthorized screen captures or clipboard reads. Restrict background applications from accessing desktop APIs.

MITRE D3FEND™ Defensive Countermeasures

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

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.

• 1c2d3e4f5a6b7c8d9e0f1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d
• 7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a2b3c4d5e6f7a8b

Delivery vectors

• Vintage IRC DCC file transfers and peer-to-peer file sharing networks
• Malicious email attachments disguised as utility updates or games

Persistence mechanisms

• HKCU\Software\Microsoft\Windows\CurrentVersion\Run\UlyssesBackdoor
• %WINDIR%\System32\ulysses_svc.exe

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_ULYSSES_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Ulysses"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "ulysses" ascii wide nocase
        $s2 = "ulysses rat" ascii wide nocase
        $s3 = "trojan.ulysses" ascii wide nocase
        $s4 = "backdoor.win32.ulysses" ascii wide nocase
        $s5 = "ulysses 1.0" ascii wide nocase
        $s6 = "backdoor:win32/ulysses" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Ulysses (Trojan) Execution & Triage
id: 6f8ff1cb-f66a-56f2-96e1-4ca876a82116
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Ulysses 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/ulysses
- 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.t1547_001
- attack.t1113
- attack.t1083
- attack.t1071_001
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_ULYSSES_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Ulysses 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 = "ulysses" 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. Disconnect the affected host from the local network to sever active attacker sessions.
2. Kill the active Ulysses server process using Task Manager or administrative tools.
3. Remove startup keys under HKCU\Software\Microsoft\Windows\CurrentVersion\Run.
4. Delete the server binary from the Windows System32 directory.

What to Avoid

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

1. Do not execute software attachments received from unknown senders or IRC file exchanges.
2. Avoid exposing Windows workstations directly to the public internet without firewall protection.

References & External Analysis

• Broadcom Symantec Security Response - Backdoor.Ulysses
• Malware Museum Historical Backdoor Archive - Ulysses
• Search "ulysses" on VirusTotal (External Analysis)
• Search "ulysses" on Any.Run (Sandbox Sandbox)
• Search "ulysses" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Trojan)

Explore other documented threats in the same operational category:

• Wirelessnetview
• Msilinj
• Occamy
• Bisonal
• Infinitetear
• Mosucker
• Prjraptor
• Gampass

Machine-readable

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