Data Security

Data Exfiltration: Detecting and Preventing Data Theft

February 15, 2024

Data Exfiltration: Detecting and Preventing Data Theft

What is Data Exfiltration?

Data exfiltration, also known as data extrusion or data theft, refers to the unauthorized transfer of sensitive information from a computer or server to an external destination or recipient. It is a form of cyber attack and data breach that aims to steal confidential or proprietary data from an organization.

Data exfiltration can occur through various channels:

Email – Sensitive data sent via email to unauthorized recipients.
Web uploads – Data uploaded to third-party web applications or storage.
External devices – Copying data to removable media like USB drives.
FTP/SFTP – Using file transfer protocols to send data externally.
Cloud sync – Syncing with unauthorized cloud storage accounts.
DNS tunneling – Using DNS queries to tunnel data out.

The main goals of data exfiltration are to:

Steal intellectual property, financial information, or personal data.
Breach data privacy regulations and laws.
Enable future cyber attacks with stolen data.
Damage an organization’s reputation and revenue.

Why is Data Exfiltration a Major Threat?

Data exfiltration poses a serious cybersecurity threat for several reasons:

Sensitive data loss – Breaches can lead to loss of sensitive PII, financial records, healthcare data, trade secrets etc. This can have legal, regulatory and financial impact.
Reputational damage – Data breaches harm consumer and shareholder trust in an organization. Stock prices may also take a hit.
Compliance violations – Losing customer data may violate privacy laws like GDPR and incur heavy fines.
Enables more attacks – Stolen data can empower further phishing, identity theft, and social engineering attacks.
Difficult to detect – Sneaky exfiltration using encrypted tunnels is hard to catch with firewalls and filters.
Insider threats – Staff with privileged access are responsible for a major chunk of data theft incidents.

How Does Data Exfiltration Occur?

Cyber criminals use various techniques to stealthily exfiltrate sensitive data:

Email Exfiltration

Emailing files as attachments to unauthorized or private accounts.
Forwarding sensitive emails outside the organization.
Using webmail services and encryption to cover tracks.

External Storage Exfiltration

Copying files to external USB drives and devices.
Uploading data to unauthorized cloud sync and storage accounts.
Transferring data to network file shares.

Network Exfiltration

Using secure tunnels like SSH or VPNs to send data over the network.
DNS tunneling to encode data into DNS queries and answers.
Covering tracks using encryption protocols like SSL/TLS during transfers.

Signs That Data Exfiltration May Be Occurring

Some indicators that data exfiltration may be happening within your organization:

Unexplained spikes in outbound network traffic and internet bandwidth usage.
Employees copying unusually large amounts of data to USB devices.
Sensitive documents and files going missing or getting deleted.
Appearance of unknown applications and programs on company networks.
Strange DNS requests to new domains outside the organization.
Sudden encryption of outbound network traffic.
Employees resignation who had access to confidential data.

How to Prevent Data Exfiltration

Here are some key measures organizations can take to prevent and detect data exfiltration:

Employee Education

Establish security awareness programs to train staff on data handling policies.
Highlight risks of data exfiltration by insiders and via email.
Set guidelines for acceptable usage of external devices and cloud accounts.

Access Controls

Institute the principle of least privilege access to data.
Monitor access to confidential directories and files.
Disable USB ports or restrict device usage where possible.

Network Defenses

Leverage data loss prevention (DLP) systems to detect potential data leaks.
Inspect encrypted traffic for unauthorized communications.
Block access to suspicious external IPs and domains.

Monitoring and Logging

Monitor inbound and outbound network traffic for anomalies.
Log DNS requests, email attachments sent, and files copied externally.
Detect use of tunneling protocols like DNS and SSH.

Conclusion

Data exfiltration is a severe cyber threat that can result in loss of sensitive customer data, intellectual property theft, and compliance violations. Organizations need layered defenses like access controls, network monitoring, and employee education to prevent data from getting stolen or leaked out. Identifying potential data breach risks and establishing proper data security protocols is essential for protecting confidential information in the modern threat landscape.