Glossary
Data Exfiltration
Data exfiltration is the getaway - it's when hackers actually steal your data by sending it out of your network to themselves. They might compress it, encrypt it, or disguise it as normal traffic. Once data leaves your network, you've lost control of it forever.
What is Data Exfiltration?
The unauthorized transfer of data from a computer or network, typically the final stage of a cyberattack where stolen information is sent to attacker-controlled systems.
Why Should You Care?
Data exfiltration represents the point of no return in a breach—once stolen data leaves your network, you lose custody and control, exposing the organization to regulatory fines, customer liability lawsuits, and competitive harm. Organizations face mandatory breach notification laws (like GDPR, HIPAA, state privacy rules) that trigger costly disclosure requirements and investigation costs. The reputational damage from confirming that sensitive customer, employee, or intellectual property data was stolen often outweighs the immediate technical remediation cost.
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Real-World Example
In the MOVEit Transfer vulnerability exploitation campaign (2023), attackers exfiltrated data from many organizations across multiple sectors. Victims confirmed that customer PII and other sensitive records were stolen, with some data later appearing on extortion leak sites. The incident demonstrated how exfiltration can occur silently—often before detection—leaving victims unaware that sensitive data had already left their network and entered the criminal supply chain.
How to Protect Against Data Exfiltration
- 1.
Implement Data Loss Prevention (DLP) tools
- 2.
Monitor for large outbound data transfers
- 3.
Restrict USB and cloud storage usage
Related Terms
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