Data is one of the most valuable assets an organization holds, which also makes it an attractive target for attackers. A successful cyberattack does not always end with unauthorized access. In many cases, the objective is to find sensitive information and move it outside the organization’s environment.
A recent example is Analog Devices, which disclosed in July 2026 that it had identified unauthorized access to certain company systems in June. The company confirmed that certain files had been exfiltrated, while its investigation into the nature and scope of the affected information remained ongoing.
Data exfiltration can occur through compromised accounts, malware, social engineering, vulnerable systems, or even legitimate users. Understanding how the threat occurs, recognizing the signs of potential exfiltration, and knowing how to prevent unauthorized data transfers are essential to protecting sensitive information.
What is data exfiltration?
Data exfiltration is the unauthorized, intentional transfer, copying, or theft of data from a personal or corporate computer, server, or network to an external location controlled by a threat actor. In cybersecurity incidents, the term commonly describes an attacker or malicious insider deliberately moving stolen information outside the organization.
The data involved can include customer or personal information, employee records, financial information, credentials, intellectual property, source code, business documents, and other confidential information.
Also known as data extrusion or data exportation, data exfiltration can be carried out manually or automatically through malware. The destination may be an attacker-controlled server, external storage, a cloud service, or another location outside the organization’s environment.
Unauthorized access alone does not mean data exfiltration has occurred. Exfiltration involves the information actually being transferred or removed from the affected environment.
How does data exfiltration happen?
Data exfiltration can originate from outside or inside an organization. Attackers may first compromise an account or system and then locate and collect valuable information before transferring it elsewhere. Malicious insiders can use legitimate access to perform a similar action.
Accidental data exposure is generally described as data leakage rather than deliberate exfiltration. However, both situations can involve sensitive information leaving its intended environment and require appropriate security measures.
External attackers
External attackers typically gain an initial foothold through methods such as phishing, malware, compromised credentials, or vulnerabilities in systems and apps. Once inside, they can identify sensitive files, collect the information, and transfer it to an external destination.
Phishing can give attackers valid credentials or persuade employees to provide information directly. Malware can automate the process by searching for sensitive files and sending collected data to an external destination. Vulnerability exploits can also provide access to systems containing valuable information.
Attackers may use legitimate services, such as cloud storage or communication channels, to move stolen information. This can make unauthorized transfers harder to distinguish from normal business activity.
Insider threats
Employees, contractors, and other authorized users can also become a source of data exfiltration. A malicious insider may deliberately copy sensitive information for financial gain, espionage, or personal reasons.
An employee may also accidentally expose or transfer sensitive information, such as sending a confidential file to the wrong recipient or copying it to an unsecured device. These incidents are more accurately described as data leakage when there is no deliberate attempt to remove the information.
The distinction matters because authorized users may already have legitimate access to the data. Security teams therefore need visibility into how sensitive information is accessed, copied, and transferred, rather than relying only on perimeter defenses.
Data exfiltration vs. Data leakage vs. Data breach
These terms are related but describe different aspects of a security incident.
| Term | What it means | Example |
|---|---|---|
| Data leakage | Sensitive information is accidentally exposed or transferred to an unauthorized party. | An employee uploads a confidential file to publicly accessible storage. |
| Data breach | An unauthorized party gains access to sensitive or confidential information. | An attacker uses stolen credentials to access a customer database. |
| Data exfiltration | Information is transferred from a system or environment without authorization, commonly as part of deliberate data theft. | An attacker copies customer records to an external server after compromising an account. |
A data breach can result in data exfiltration, but the two are not the same. Unauthorized access becomes exfiltration when information is actually copied or transferred outside the affected environment. Similarly, a data leak can occur without an attacker deliberately stealing the exposed information.
Common data exfiltration techniques
Attackers can use different methods to move stolen information outside an organization. The technique often depends on the data involved, the attacker’s access, and the security measures in place.
1. Exfiltration through malware
Malware can automate data theft after gaining access to a device or network. It may search for sensitive files, collect credentials or other information, and send the collected data to an external destination.
2. Phishing and social engineering
Phishing and other social engineering techniques target users rather than systems directly. An attacker may trick an employee into revealing credentials, opening a malicious link, downloading malware, or directly sharing sensitive information.
3. Exfiltration over C2 channels
Attackers can use command-and-control (C2) channels established by malware to communicate with compromised systems and transfer collected data. Using an existing malicious communication channel can help the transfer blend into other network activity.
4. DNS and other alternative protocols
DNS can be abused to create a covert channel for moving data outside a network. An attacker can encode information into DNS requests and responses, allowing data to leave through a protocol that organizations routinely use. Other protocols can also be abused for data exfiltration.
5. Cloud storage and file sharing services
Attackers or insiders can use cloud storage and file sharing services to move sensitive information outside the organization. Because these services may also be part of normal business activity, unauthorized transfers can be difficult to distinguish from legitimate use without appropriate monitoring.
6. Email-based exfiltration
Email provides a straightforward way to move sensitive files or information outside an organization. An attacker with access to a compromised mailbox may send data to external recipients, while a malicious insider may deliberately send confidential files to a personal account.
7. Removable media and USB devices
USB drives and other removable storage can provide a direct path for copying data from an organization’s systems. A malicious insider may use them to remove sensitive information, while accidental transfers can also expose data when unsecured devices are used.
8. Data compression and encryption
Attackers may compress or encrypt collected data before transferring it. Compression can reduce the amount of data that needs to be transmitted, while encryption can make the contents difficult to inspect during transfer.
9. Steganography
Steganography hides information within another file, such as an image or audio file. An attacker can use this technique to conceal stolen data and make the resulting transfer less obvious.
What are the risks of data exfiltration?
The impact depends on what was stolen and how the information is used. For an organization, the consequences can extend well beyond the loss of individual files.
Sensitive customer or employee information can be used for identity theft, fraud, or further attacks. Stolen intellectual property can expose product plans, source code, research, or trade secrets. Organizations may also face regulatory penalties when exfiltrated data includes information subject to privacy or data protection requirements.
Additionally, data exfiltration can disrupt operations and damage customer trust. In ransomware attacks, attackers may exfiltrate data before encrypting systems and then use the stolen information to increase pressure on the victim.
How to detect data exfiltration
Detecting data exfiltration requires visibility into how users, devices, and data behave across the environment. Individual indicators may not confirm an incident, but unusual activity can help security teams identify where further investigation is needed.
1. Unusual outbound network traffic
Unexpected connections to unfamiliar external destinations can indicate that data is being transferred outside the organization. Security teams can investigate unusual destinations, protocols, connection patterns, or traffic volumes to identify potentially unauthorized transfers.
2. Large or unusual data transfers
A sudden increase in outbound traffic or a large transfer from a device that normally sends little data can warrant investigation. Transfers occurring at unusual times or from unexpected systems can provide additional context.
3. Unexpected access to sensitive files
Access to sensitive files or databases that falls outside a user’s normal activity can be an early warning sign. This becomes more significant when unusual file access is followed by external transfers.
4. Unusual login or account activity
Repeated failed logins, logins from unfamiliar locations, or unexpected use of privileged accounts can indicate a compromised account. If the same account subsequently accesses and transfers sensitive information, the activity warrants investigation.
5. Unexpected cloud storage or file sharing activity
Uploads to personal cloud storage, unfamiliar file sharing services, or unexpected external accounts can indicate an attempt to move data outside approved environments.
6. Unusual use of removable storage
Unexpected connections of USB drives or external storage devices can indicate an attempt to copy data from an endpoint. Monitoring device connections and access activity can help identify such events.
7. Compressed or encrypted data transfers
Unexpected transfers involving large compressed archives or encrypted data can be useful indicators for investigation, particularly when they occur alongside other unusual account, file, or network activity.
How to prevent data exfiltration?
Preventing data exfiltration requires safeguards across identities, endpoints, networks, apps, and users. No single security layer addresses every possible path through which data can leave an organization.
1. Implement data loss prevention (DLP)
DLP policies can identify and restrict risky ways of transferring sensitive information. Depending on the organization’s requirements, this can include removable storage, email, web apps, cloud services, and other channels through which sensitive data may leave the environment.
2. Strengthen identity and access security
Strong authentication and least privilege access reduce the opportunity for compromised accounts to reach sensitive information. Conditional access can also require users and devices to meet defined security requirements before accessing protected resources.
3. Secure endpoints and removable devices
Endpoints are commonly used to access, copy, and transfer business data. Restricting unauthorized removable devices, requiring appropriate encryption, and applying endpoint security policies can reduce the risk of sensitive information being copied to external media.
4. Monitor network and outbound traffic
Network monitoring helps identify unusual destinations, protocols, connection patterns, and data volumes. Security teams can use this visibility to investigate potential exfiltration attempts and identify compromised systems.
5. Secure email, web, and cloud channels
Email, web apps, and cloud storage can all become paths for unauthorized data transfer. Filtering malicious destinations, restricting access to unauthorized services, and monitoring external sharing can reduce exposure across these channels.
6. Train employees
Employees can unintentionally expose sensitive information by sending files to the wrong recipient, using personal cloud storage, or connecting unauthorized devices. Security awareness training helps users recognize phishing attempts and understand how organizational data should be handled.
Data exfiltration prevention using endpoint DLP tool
Data can leave an organization through multiple channels, so preventing exfiltration requires protection across identities, networks, email, cloud services, and endpoints. At the endpoint level, restricting the use of removable storage and peripheral devices can help reduce the risk of unauthorized data transfers.
Veltar endpoint DLP solution addresses this endpoint layer, helping IT teams manage access to supported peripheral devices across Windows, macOS, and Linux endpoints.
Key capabilities include:
- Flexible device access policies: Allow, restrict, or block supported USB drives, external storage, and other peripheral devices, with access levels such as read/write, read-only, or block.
- Context-based restrictions: Apply device access restrictions based on conditions such as IP address, day of the week, and start and end times, with timezone-based settings where supported.
- Encryption enforcement and visibility: Restrict access to storage devices that do not meet encryption requirements (where supported), and maintain device access logs for auditing and investigation.
Veltar also provides complementary endpoint security capabilities, including Secure Web Gateway and automated endpoint compliance. These help organizations manage web access and endpoint security configurations as part of a broader data protection strategy.
Strengthen your defenses against data exfiltration
Data exfiltration can involve compromised accounts, malicious software, insiders, network channels, cloud services, or removable devices. Preventing it requires security measures that address these different paths while giving security teams visibility into suspicious activity.
Veltar adds an endpoint-focused layer to this strategy. With Endpoint DLP, organizations can restrict unauthorized use of supported storage and peripheral devices and reduce specific opportunities for sensitive data to leave managed endpoints.
Veltar’s endpoint security capabilities can complement this protection by addressing web access and endpoint compliance risks. With Veltar, endpoint security and data protection can fit into your organization’s broader approach to preventing data exfiltration.
