Dueling Network 2017 Data Breach
ObscureIQ Breach Intelligence
Low SeverityWebsite / service breach
Dueling Network Yu-Gi-Oh! Online Game Breach (2017): 6.5 Million Player Accounts Including Passwords Exposed
Defunct fan-made online Yu-Gi-Oh trading card game.
Verified by ObscureIQ Intelligence
17/100Breach Risk Index
3Data Value
25Market Recency
511dSince Breach
Breach Intelligence Summary
Entity: Dueling Network · Actor: Unknown · Sources: 9 references
Attack: Web Application Exploit
Profile: Platform · Online gaming and player community services · Yu-Gi-Oh dueling game platform · Global
Timeline: Breach (2017-03-29) · Indexed (Feb 12, 2025) · Year (2017)
Exposure: 6.5M records · 4 fields: Email Address, IP Address, Password, Username
Status: Confirmed
Executive Summary
In 2017, a database from the by-then-defunct Dueling Network surfaced containing approximately 6.48 million accounts. Exposed data included email addresses, IP addresses, usernames, and passwords stored as MD5 hashes. HIBP indexed about 5.5 million unique addresses, with roughly 63% already present from prior breaches.
ObscureIQ assessment: Exposure enables account takeover, phishing, and harassment. Competitive history and community data can also support cross-platform identity linkage.
Breach Impact
Because passwords were stored as unsalted MD5, a large share were trivially crackable, exposing reused credentials to stuffing attacks despite the service itself being defunct.
About Dueling Network
Dueling Network was a browser-based fan project that let players simulate the Yu-Gi-Oh trading card game online. It operated a large registered user base before ceasing operations.
Why They Hold Your Data
Online dueling-game platforms collect player accounts, emails, gameplay history, deck or match activity, and community participation tied to competitive gaming workflows.
Recent Developments
The site shut down in 2016 following legal pressure from the franchise rights holder, and the domain is no longer active.
Data Points Exposed
4 verified field types
Email Address
IP Address
Password Critical
Username
Field names are shown in full for clarity and search visibility. Canonical machine keys are emitted only in this page’s structured data.
Exploitation & Downstream Threats
Threat Activity:High
Primary downstream threats:
- Credential stuffing against reused passwords across other platforms
- Targeted phishing campaigns using exposed email addresses
Threat vectors:
- Phishing, credential stuffing & account takeover
- Geolocation & account flagging
- Credential stuffing & account takeover
- Cross-platform tracking & credential stuffing
Recommended Actions
If you believe your information may be included:
Change Reused Passwords
Update this account and anywhere you reused the password; use a manager.
Enable MFA Everywhere
Turn on multi-factor authentication on email first, then financial accounts.
Report & Recover
If you spot misuse, start an official recovery plan and report fraud.
Frequently Asked Questions
What happened in the Dueling Network breach?▾
In 2017, a database from the by-then-defunct Dueling Network surfaced containing approximately 6.48 million accounts. Exposed data included email addresses, IP addresses, usernames, and passwords stored as MD5 hashes. HIBP indexed about 5.5 million unique addresses, with roughly 63% already present…
What data was exposed?▾
Verified fields include Email Address, IP Address, Password, Username.
What should I do if I was affected?▾
Change reused passwords, enable MFA, and (if identity or financial data is involved) freeze your credit and monitor your accounts.
Sources & References
Every claim on this page is traceable. This breach draws on:
Breach Index
Breach Index
Cross-source
9ghz
Cross-source
BreachForums_Official_Index
Cross-source
DataViper.io
Cross-source
DeepSearch
Cross-source
Leaked.Domains
Cross-source
leakfind
ObscureIQ Intelligence
ObscureIQ proprietary analysis
Protect Yourself
Check If You're Affected
Enter your email to check whether your data appears in this breach. We’ll send a 6-digit code to confirm it’s your address.
Get Free Breach Alerts
Be the first to know when new breaches are disclosed. Free forever — confirm your email with a 6-digit code.
High-Risk? Get an Exposure Audit
Executives, public figures, and high-visibility operators can receive tailored exposure intelligence and hardening guidance.
Request Consultation