China Software Developer Network 2011 Data Breach
Platform · Developer content and resources · Technical community platform · China
China Software Developer Network (CSDN) Breach (2011): 6.4 Million User Accounts Including Plaintext Passwords Exposed
Chinese developer community and technology content platform.
Confirmed · ObscureIQ Intelligence
Breach Risk Index i
34/100
Lower riskHigher risk
Moderate: notable exposure with meaningful misuse potential.
Data Sensitivity i
StandardExposed data is largely lower-sensitivity. Standard identity-protection precautions are advised.
6.4MRecords
2011Year
The Breach Risk Index (BRI) is a proprietary 0–100 score rating how dangerous a breach is right now, based on how recently the data has been circulating on the dark web and how valuable it is to attackers.
Breach Summary
On 21 December 2011, the CSDN user database was publicly leaked, exposing about 6.4 million accounts with email addresses, usernames, and plaintext passwords. CSDN stated the leaked data dated to around September 2010, from a period before it stopped storing passwords in clear text. The incident helped trigger a wider wave of Chinese site breach disclosures that month.
Full threat analysis, exploitation vectors, and principal guidance below.
11 additional sections · verified field analysis · defensive doctrine
Querying breach corpus…
Cross-referencing exposed field types…
Resolving threat-actor attribution…
Compiling principal risk advisory…
6.4M records analyzed
About China Software Developer Network
CSDN (China Software Developer Network) is one of China’s largest online communities for software developers, offering forums, blogs, and technical resources.
Why They Hold Your Data
Developer platforms collect user accounts, emails, usernames, passwords, and technical activity tied to coding resources, forums, and software sharing.
Recent Developments
Chinese authorities arrested individuals in connection with the incident, and CSDN moved away from clear-text password storage after the exposure.
Data Points Exposed
3 verified field types
Email Address
Password High
Username
Breach Impact
Plaintext developer credentials are immediately usable and, given the technical user base, elevate risk of downstream compromise of code repositories and other systems through password reuse.
Exploitation & Downstream Threats
• Credential stuffing against reused passwords across other platforms | • Targeted phishing campaigns using exposed email addresses
Principal Risk Advisory
What this means for a principal
A social-platform breach: profile and contact-graph data supports impersonation, enrichment and social engineering. For a high-profile principal the main risk is credible impersonation and enrichment of existing exposure.
What You Should Do
- Reset any reused passwords and enable MFA on email first, then financial accounts.
- Do not use unofficial 'am I affected' lookups; several are themselves harvesting operations.
How ObscureIQ Can Help
- Corpus confirmation: determine whether and where the principal (plus household and staff) appear in this dataset and which specific fields are exposed for them.
- Exposure mapping: cross-reference the exposed identifiers against broker-available data to size and prioritize the principal's wider footprint.
- ThreatWatch tuned to this incident's identifiers and misuse pattern (impersonation and targeting patterns, not generic credential monitoring).
This breach is linked to the China 2011-2012 breach wave campaign (8 related breaches tracked by ObscureIQ). See the full campaign analysis →
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