Data Exfiltration: How to prevent it

Data exfiltration is one of the biggest – and potentially costliest – cybersecurity threats facing any organization. This unauthorized transmission of data out of an organization can happen in any number of ways but is most often carried out by cybercriminals.

What is Data Exfiltration?

Data exfiltration is a type of data breach involving the unauthorized copying or transferring of data from one device to another. Cyberattackers can use both manual access and automated malware attacks to exfiltrate data from companies or individuals.

Any removal of data from a device qualifies as data exfiltration, even if a user has the proper permissions to access or work with that data. However, the typical data exfiltration definition classifies data extrusion tactics as acts of intentional data theft performed by malicious actors.

How does Data Exfiltration occur?

Data exfiltration occurs in two ways, through outsider attacks, and via insider threats. Both are major risks, and organizations must ensure their data is protected by detecting and preventing data exfiltration at all times.

An attack from outside the organization occurs when an individual infiltrates a network to steal corporate data and potentially user credentials. This typically is a result of a cybercriminal injecting malware onto a device, such as a computer or a smartphone, that is connected to a corporate network.

Some strands of malware are designed to spread across an organization’s network and infiltrate other devices, searching for sensitive corporate data in an attempt to exfiltrate information. Other types of malware will lay dormant on a network to avoid detection by organizations’ security systems until data is exfiltrated subversively or information is gradually collected over some time.

Attacks can result from malicious insiders stealing their own organization’s data and sending documents to their personal email addresses or cloud storage services, potentially selling them to cybercriminals. They can also be caused by careless employee behavior that sees corporate data fall into the hands of bad actors.

Common attacks

What are the most common data exfiltration techniques?

Email

Some email breaches are unintentional—caused by employees emailing sensitive information to the wrong party or an intended recipient forwarding it to an unauthorized recipient—but most email data exfiltration is malicious. Phishing emails purport to be from reputable institutions to lure recipients into divulging sensitive information. While standard phishing emails tend to be generic, spear phishing emails are specific, seeming like they’re from a trusted sender. Clicking on links in those emails can launch malware or ransomware that could infect an entire corporate network, leading to massive data leaks.

Unsecured devices

Ever copied the information onto a thumb drive or personal laptop? Logged into public Wi-Fi? Any time you use a device that isn’t secure, it invites hackers to steal information. A careless employee can make it even easier by misplacing or losing their phone, USB, or laptop.

Unauthorized software or websites

Installing unauthorized software onto a company computer is a common way that malware or ransomware is introduced into a network, potentially transferring sensitive data to malicious out.

How to protect against Data Exfiltration

Here are several strategies that organizations can put in place to prevent data exfiltration:

• Deploy data loss prevention (DLP). DLP is a set of technology and business policies to make sure end users do not send sensitive or confidential data outside the organization. A DLP system scans all outbound emails to look for pre-determined patterns that might indicate sensitive data, including credit card numbers, Social Security numbers, and HIPPA medical terms. Messages containing this type of sensitive data are automatically encrypted or blocked from being sent out, depending on the policy.
• Set up encryption policies. Establish policies to encrypt sensitive data while it’s in transit. Encrypted messages cannot be intercepted or tampered with by hackers.
• Prevent phishing attacks. Phishing attacks are commonly used by malicious actors in data exfiltration attacks. Investing in good anti-phishing technologies that will detect and block phishing attacks is a must to prevent data loss.
• Revoke data access for former employees and contractors. Organizations must stay on top of who has access to their sensitive data and revoke access to employees or partners as soon as a business relationship is over. Leaving access open for even an extra day may cause a serious security breach.
• Educate your employees. Invest in educating your users on how to recognize phishing attacks that may lead to data exfiltration and how to follow internal policies on data security. The number one cause of data loss is human error, so make sure your employees understand how to keep company data secure.
• Back up your data. Unfortunately, some organizations may face a security breach that will lead to data loss. Organizations need to be prepared and back up all of their data so they can quickly restore any lost data without a negative impact on their business operations and productivity.

Conclusion

Whether the result of an employee mistake or a deliberate attack, data exfiltration can have devastating impacts on an organization including financial losses, legal action, reputational damage, and customer impact. Preventing data extraction and mitigating the impact of data exfiltration attacks with a comprehensive cybersecurity plan should be a strategic priority.