Data exfiltration is the unauthorized transmission of data from an IT asset to an external destination. This includes removing data from endpoints, cloud applications, or even physical on-premises media. Hackers can use this data to gain leverage over their victims and conduct extortion attacks. 

Data exfiltration is a critical security risk because data breaches can lead to catastrophic damages. At the same time, detecting data exfiltration can be extremely difficult—hackers have elaborate methods for transferring sensitive materials off victim’s networks undetected. 

How does data exfiltration happen? 

There is an incredible variety of data exfiltration attacks and strategies, but most fall into one of two categories:  

• Outsider attacks involve external threat actors gaining access to sensitive data and transferring it to an asset they control. These attacks might involve phishing, malware, prompt injection attacks, and others. 

• Insider threats originate from within the organization. In this scenario, a user or employee transfers data to an unauthorized external asset. This can be deliberate or accidental, and your incident response team will need to investigate to tell the difference. 

In a deliberate insider threat scenario, a malicious insider copies sensitive data to an unauthorized asset and removes it from the organization’s control. This could mean anything from sending files to a personal email address or printing out sensitive documents and carrying the paper home. 

In an accidental insider threat scenario, an employee may carelessly store sensitive data on a publicly exposed asset. Public cloud storage containers like AWS S3 Buckets or Azure Blob storage are common examples because they are easily misconfigured. 

Types of data exfiltration 

Some of the common types of data exfiltration threats include: 

• Database leaks. This is the unintentional exposure of sensitive information. It usually happens as a result of human error and inadequate data security policies. However, it can also happen because of undiscovered software vulnerabilities. 

• Network traffic leaks. Network traffic can leak to unauthorized external assets for a variety of reasons. Sometimes insider threats are intentionally diverting traffic to attacker-controlled assets. In other cases, the network might be routing data through inadequately secured infrastructure. 

• Unauthorized sharing. Employees who overshare sensitive data with customers, partners, and one another increase the risk of data exfiltration. This is especially true when visibility-reducing shadow IT assets are involved. 

• Corporate email leaks. Corporate leaders necessarily handle sensitive data as part of their daily routine. Attackers may infiltrate their inboxes and conduct Business Email Compromise (BEC) attacks that lead to data exfiltration. 

• Malware attacks. Many malware variants include some form of data exfiltration functionality. Advanced malware attacks may involve months of painstakingly slow exfiltration, calibrated precisely to avoid detection. 

How to prevent data exfiltration 

Enterprise IT leaders have a variety of options for mitigating the risk of data exfiltration. Some of the successful strategies you can use include:  

• Data loss prevention (DLP). These tools monitor network traffic, user activity, and email content for sensitive data. For example, Proofpoint can trigger alerts when outgoing emails contain suspicious data (like nine-digit numbers that correspond to the Social Security Number format). 

• Strong authorization policies. Secure passwords, multi-factor authentication, and robust Identify and Access Management (IAM) solutions help prevent attackers from carrying out credential-based attacks. 

• Data encryption. Encryption acts as an additional line of defense, preventing attackers from using exfiltrated data even when they are successful. To understand the data, attackers will have to find the decryption key, which increases their chances of getting caught. 

• Zero trust architecture. Organizations built around zero trust principles are much less likely to face catastrophic data exfiltration attacks. Networks designed around microsegmentation and the principle of least privilege give attackers fewer opportunities to access and steal data. 

• Vulnerability assessments and penetration testing. Organizations that regularly pursue cybersecurity hardening exercises are less likely to keep vulnerabilities exposed for long. By proactively seeking out these vulnerabilities, security leaders can close security gaps before threat actors exploit them. 

How to detect data exfiltration 

No organization should rely exclusively on prevention-based security controls against data exfiltration. There is always a chance that a sufficiently advanced threat actor bypasses those controls. To catch them early and mitigate risk, security leaders rely on the following: 

• Security Information and Event Management (SIEM). SIEM platforms collect and analyze log data from every corner of your tech stack. They trigger alerts according to detection rules that correspond to specific indicators of compromise. 

• User and Entity Behavioral Analytics (UEBA). UEBA platforms dramatically improve SIEM performance against insider threats by continuously monitoring authorized users and assets. When they exhibit behavior that deviates from their established routine, the platform triggers raises the level of risk. 

• Network Detection and Response (NDR). These systems grant security teams visibility into network traffic flows. This enables greater control and incident response capabilities over network threats, including data exfiltration attacks. 

• Endpoint Detection and Response (EDR). By monitoring data usage at the endpoint level, EDR solutions can catch data leaks occurring on mobile devices, laptops, and servers. When enhanced with automatic response capabilities, these tools can neutralize threats the moment they are detected. 

• Proactive threat hunting. Security leaders that invest in proactive threat hunting may find evidence of data exfiltration in business units or activities that would otherwise be overlooked. Threat hunters may conduct investigations assuming that data exfiltration is already taking place somewhere in the network. 

• Data observability. By enabling connectivity between all network assets, Cribl removes some of the obstacles IT leaders encounter when trying to obtain true unlimited visibility and enables comprehensive vulnerability management. 

Protect your data from exfiltration with Lumifi 

Lumifi leverages industry-leading expertise and its own proprietary SOC automation service, ShieldVision, to neutralize data exfiltration risks. Gain unlimited visibility into network data flows and block sensitive information from leaving your network before it’s too late. 

Our team of diligent US-based analysts work round-the-clock from our SOC 2 Type II-certified Security Operations Center (SOC), delivering 24x7x365 coverage against data exfiltration threats using best-of-breed technologies integrated through our proprietary platform. Speak to an expert to find out more.