Data Exfiltration: Definition, Types, Methods, Detection, and Prevention

One of the largest and perhaps most expensive cybersecurity dangers facing any firm is data exfiltration. This unauthorized transmission of data out of an organization can happen in any number of ways but is most typically carried out by cybercriminals.

Today, data exfiltration is a major risk for organizations. 61 percent of security professionals had encountered a data breach at their current employers, according to recent research. According to the Identity Theft Resource Center (ITRC), the vast majority (92%) of data breaches in the privacy sector in the first quarter of 2022 were caused by cyberattacks rather than human error, such as misdirected emails. According to the ITRC, the total number of personal data breaches in 2021 hit an all-time high, with 93% including sensitive data. With more stringent data privacy compliance standards, such as GDPR and the California Consumer Privacy Act, the stakes for reporting data exfiltration occurrences have also increased significantly.

In this article, we will discuss what is data exfiltration, the types of data exfiltration, data exfiltration attacks, and how to detect data exfiltration, and also prevent it.

What is Data Exfiltration?

Data exfiltration is a type of security breach which happens when data belonging to an individual or organization is improperly copied. Data exfiltration may be carried out manually by a person with physical access to a computer, or it can be carried out automatically using malicious network code.Data exfiltration is typically targeted assaults where the main goal of the hacker is to locate and copy particular data from the target machine. Through the installation of a portable media device or a remote program, the hackers get access to the target computer. According to statistics, data exfiltration mostly happens on devices using vendor-set default passwords or passwords that are widely used.

Data exfiltration is often difficult to detect. As it includes the transfer or movement of data inside and outside a company's network, it frequently closely resembles or imitates ordinary network activity, enabling significant data loss events to go undetected until data exfiltration has occurred. And if the most precious information of your business is in the hands of hackers, the harm may be immense.

The types of data sought in data exfiltration attacks are as follows:

• Information pertinent to strategic decision-making

• Encryption keys

• Usernames, associated passwords, and other information connected to system authentication

• Social security numbers and other personally identifiable information (PII)

• Individual financial details

• Email addresses

How Does Data Exfiltration Work?

Both external attacks and internal threats might result in data exfiltration. Organizations must constantly detect and prevent data exfiltration in order to secure their data from both of these big hazards.

Outsiders who break into the network and steal user information, intellectual property, and business secrets can exfiltrate data. Malware injection into an endpoint, such as a computer or mobile device connected to the business network, is the typical starting point of external attacks. The data is exfiltrated by the malware to a remote server that is under the control of an outsider, who may then sell or publicize it.

Furthermore, Advanced Persistent Threats (APTs) are a kind of cyber assault whose main objective is often data exfiltration. APTs continuously and aggressively target certain firms or organizations in order to access or steal restricted data. APTs aim to acquire access to a network while remaining undetected while they silently search for the most valuable or targeted data, such as trade secrets, intellectual property, financial information, and sensitive consumer data.

APTs may utilize social engineering tactics or contextually appropriate phishing emails to get a company's users to mistakenly open messages containing malicious scripts, which may then be used to install further malware on the company's network. In the step that follows this vulnerability, hackers use data collecting and monitoring tools to determine the target information. Once the required data and assets have been identified, they are transferred via data exfiltration procedures.

When an insider moves data outside of the network, such as by emailing it to a personal or non-work address or copying it to an unsafe cloud storage service or software-as-a-service (SaaS) product, data exfiltration is possible. Employees who are simply attempting to do their jobs frequently carry out these acts with good intentions, but by removing the data from the security team's and the company's policies, they put it at risk.

When cybercriminals successfully exfiltrate data, they may use it to harm your company's image, for financial gain, or as a means of sabotage.

How Do Hackers Exfiltrate Data?

Different methods can be used to exfiltrate data, although hackers typically do it over a network or the internet. These assaults are frequently targeted, with the main goal being to sneak into a network or machine in order to find and copy particular data.

To shield the identity of the attacker, common tactics include anonymizing connections to servers operated by third parties. This can involve employing fileless attacks, the Dark Web, direct IP addresses, tunneling over HTTP or HTTPS, and remote code execution.

In addition to transmitting the data across their command and control (C&C) channel or an other channel, the hackers' exfiltration tactics for collecting data may also entail imposing size constraints on the transmission.

Typically, hackers get illegal access to data by establishing a secure shell (SSH) connection between a hacked computer and C&C servers. Once the connection has been established, the hackers order the hacked host to send the desired data to their server. The amount of time required to transmit the data depends on the file size, the uplink speed, and the system capabilities of both sites. In order to maintain the data's integrity, hackers remove stolen information from the server where it was obtained. Additionally, some hackers choose to take the system down for operational security.

Furthermore, hackers use a variety of exfiltration tactics for successful data intrusions. These strategies often use one of the following methods to infiltrate the network of the targeted system and are also utilized in the majority of APT attacks:

• FTP: FTP is a common network protocol for file transmission between a client and a server. To exfiltrate data over FTP, hackers access an organization's externally accessible FTP server from a hacked host. If a network architecture lacks firewall rules that block outbound connections, hackers may simply reconnect to their system. Additionally, hackers may try to set up the FTP server with write-only access (also known as a "blind drop" server). It permits anonymous uploads but limits all other activities, including file retrieval and directory listing, enabling hackers to avoid needing credentials entirely.

• Backdoors: Hackers use backdoors (a way of circumventing regular authentication or encryption in a computer) to detect or install themselves as part of an attack. Backdoors feature built-in upload and download capabilities, akin to Remote Access Trojans (RATs). It conceals communication using ports such as 80 and 443 (for HTTP or HTTPS) and port 53 (for DNS). When they utilize HTTP to send data, hackers efficiently circumvent the connection limitation. On occasion, they must manually download the .ZIP file containing all acquired data.

• Web Applications: Hackers may access the organization's network using any browser of their choosing. Even IT managers will not be suspicious since access to websites outside the network is not out of the usual.

• WMI: WMI stands for Windows Management Instrumentation. It may be used to track the files opened by the workers or users of interest. As a result, fraudsters may quickly identify and collect these files, as well as transmit information to their server.

• Peripheral Devices: Obtaining access to peripheral devices is another prevalent method. Attackers often target different connected devices, such as microphones, webcams, and security cameras, to capture audio and video in order to monitor the actions of the targeted individuals.

• Email Server: Microsoft Outlook rule lets hackers obtain copies of the emails that the target users receive. This enables them to design a targeted phishing email to conduct a social engineering assault or, in certain instances, to immediately get private data.

What are the Types of Data Exfiltration?

Data exfiltration happens in various ways and via numerous attack techniques. Exfiltration often happens on a business network or over the internet. The most common types of data exfiltration are as follows:

• Phishing Attacks: When conducting a phishing attack, the attacker sends consumers an email that appears to be from a trustworthy organization, like the human resources department. Users will be prompted to click a link in the email that will take them to a fake website that closely resembles the official human resources portal. This fake website may have been created specifically to gather passwords, or it could have malicious scripts embedded in its code that install keyloggers or other malware in order to go to the next phase of the phishing attempt.

• Uploading Data to Insecure Devices: Employees may copy company data to USB flash drives or other unreliable hardware, such as cameras, smartphones, or external hard drives. Attackers can access the devices from there and steal the data. Using personal storage devices, a user can deliberately steal data or just copy data to do work from home. In the final scenario, a negligent worker can misplace the device or disclose data due to flaws in their home computer and network.

• Unauthorized Software or Websites: Unauthorized software installations pose a serious threat to the cybersecurity of an organization's devices. Employees may purposefully or unintentionally download illegal software that could contain malware that secretly sends user data to a remote system. If careless employees use company computers to view dubious websites, that is another method malware might enter corporate devices and networks.

• Insecure Cloud Behavior: Additional exfiltration hazards brought on by cloud services include situations in which administrators or workers make unauthorized use of the provider's features. Data exfiltration is possible for every player with the capacity to deploy code, modify virtual machines, or send requests to cloud storage. Additionally, individuals with enough access can build illegitimate services on behalf of the business or transmit data from secure containers to insecure ones.

• Outbound Emails: Attackers use permitted telecommunications infrastructures, including company phones or business email accounts, to send sensitive data through outgoing mail from secure computers to insecure private systems. The information can be sent as a file attachment, a text message, or an email with plain text. This method is most frequently used to steal source code, calendar information, pictures, financial projections, databases, and corporate correspondence. Additionally, a lot of messaging and email services automatically save drafts to the cloud. This means that someone who has access to a company's email account or another communications platform that supports saved drafts may use it to steal information.

What are the Data Exfiltration Attack Examples?

Data exfiltration may occur as a result of an outside attack or the actions of nefarious insiders. Theft of tangible objects or documents, digital transfers, automated processes as part of ongoing cyber attacks, and bad actors can exfiltrate data in a variety of ways.

Some examples of data exfiltration attacks are as follows:

• Magellan Health: On April 6, 2020, hackers used a sophisticated social engineering phishing assault to enter the server of the healthcare provider Magellan Health. An access point to Magellan Health's servers was made available by the attack, which pretended to be a client. The attacker stole private information between April 6 and 11, 2020, including names, contact information, employee identification numbers, social security numbers, and taxpayer identification numbers. Additionally, the threat actors were able to capture additional login information and passwords from some Magellan workers while simultaneously installing malware.

• U.S. multinational conglomerate: Over the course of eight years, a malicious insider at a U.S. multinational conglomerate copied 8,000 confidential files, some of which contained priceless trade secrets, in order to start a rival business. In 2021, the ex-employee was given a two-year prison term and told to pay $1.4 million in restitution.

• eBay: A breach at eBay in 2014 affected 145 million users. In this instance, a small number of leaked employee log-in credentials allowed thieves to obtain illegal access to eBay's corporate network.

• A Foreign Exchange: A foreign exchange paid a ransomware gang $2.3 million to regain access to data that had been stolen during an attack on New Year's Eve 2020. Five gigabytes of data had been stolen by the cybercriminals who had accessed the company's network.

• British Airways: After attackers stole customer data, including names, addresses, and credit card details, British Airways (BA) was fined $28 million by the UK's Information Commissioner's Office (ICO) in October 2020. In June 2018, when hackers put harmful code on BA's website, a significant data breach occurred. Over 400,000 consumers were impacted by the breach, which was entirely BA's fault, according to the ICO.

What are the Studies About Data Exfiltration?

Some of the data exfiltration statistics are as follows:

• Data exfiltration is becoming a bigger issue for companies, and many ransomware assaults now include it as a common component. Data exfiltration is now used in over nine out of ten recorded ransomware instances (89 percent), up from about 80 percent the year before, according to BlackFog's State of Ransomware report for 2022.

• A successful cyberattack occurs every 1.12 seconds, according to the FBI's 2020 Internet Crime Report. The cost of cybercrime to businesses each year is in the billions of dollars. Small firms are especially vulnerable; in 2020, they will be responsible for over 50% of data breaches in the US. Understanding how to reduce risk and cost in the event of phishing, malware, sketchy websites, and network breaches is essential to recovery.

• BlackFog's own study indicates that 2.65% of all traffic is routed to China, and 19% of all traffic is diverted to Russia. 5.67 percent of all traffic was data exfiltration to the Dark Web.

• According to McAfee's Grand Theft Data report internal actors were accountable for 43% of data loss, half of which was purposeful and half inadvertent. Data that was taken was most frequently in Microsoft Office document format (25%). Due to the greater value of private personal data than credit cards, personal information from customers and workers was the most popular target (62%).

• According to 63% of enterprises, privileged IT users present the highest insider security risk to businesses. 68 percent of companies believe they are very to somewhat vulnerable to insider threats. 78% of respondents say they don't think their procedures for managing IT privileges are very effective (Cybersecurity Insiders, 2020).

• Ransomware breaches typically cost $4.62 million in total, which is a little more than the $4.24 million average cost of a data breach. At a cost of $1.59 million on average, missed business prospects accounted for the greatest portion of breach expenses in 2021. With an average cost of $9.05 million, the United States had the highest average overall cost of a data breach in 2021. The longest data breach lifecycles were in the healthcare and banking sectors, at 329 and 233 days, respectively (IBM).

• More than 64% of financial service organizations have 1,000 or more sensitive files available to every employee. Nearly 40% of financial services organizations have more than 10,000 ghost users, and 59 percent have more than 500 passwords that never expire. More than 80% of hacker breaches use brute force or credentials that have been lost or stolen (Verizon).

How to Detect Data Exfiltration?

Data exfiltration detection is challenging and is greatly influenced by the assault strategy employed. Cybercriminals employ a wide range of sophisticated tactics, including certain legal procedures that are more evasive in their detection. Analysts may thus falsely classify the traffic from data exfiltration as typical network traffic.

More and more enterprises are utilizing automated techniques that instantly identify suspicious or anomalous communications in order to detect the presence of a malicious actor.

Some of the tools and techniques to detect data exfiltration are as follows:

• SIEM Tools: Network traffic can be continuously monitored by a Security Information and Event Management System (SIEM). Even malware used to communicate with command and control servers can be found with some SIEM solutions.

• UEBA Tools: Machine learning is used by user and entity behavior analytics (UEBA) tools to examine user and device behavioral trends. Because it can recognize unexpected file access or manipulation, UEBA is very helpful for identifying and stopping exfiltration. This implies that if insiders start exporting or accessing data they shouldn't, they will be caught even if they have valid credentials. UEBA can be integrated with your tools for preventing data loss.

• NDR Tools: The security team can annotate the network entities using Network Detection and Response (NDR) tools depending on the data classification of those things. Each organization's threat detection can then be tailored using these annotations.

• Network Monitoring: Monitoring all open port traffic to look for unusually high traffic quantities, often 50GB+ can help to detect data exfiltration. Since they could merely be legitimate business relationships, such discoveries should prompt more focused scrutiny. Connections made by businesses to unusual IP addresses could be a sign of data exfiltration. To compare against new connections, security teams should maintain an up-to-date log of all connections from authorized IP addresses.

How to Prevent Data Exfiltration?

There are many tools available to stop data exfiltration. When an attacker tries to transport sensitive data outside the network, conventional programs like firewalls and data loss prevention (DLP) tools can identify the attempt. To know when attackers are moving in, you can also use strategies like threat hunting. Some of the tools and techniques to prevent data exfiltration are as follows:

• Next-Generation Firewalls: Organizations can safeguard their networks from internal and external cyber attacks with the use of next-generation firewalls (NGFWs). They continue to offer features including network monitoring, IPsec and SSL support, and virtual private networks (VPNs). Additionally, greater traffic inspection made possible by NGFWs enables businesses to recognize and stop malware and attacks across their entire attack surface. To stop data exfiltration from new and sophisticated assaults and defend networks from new dangers, NGFWs automatically upgrade.

  Next-generation firewalls can shield networks from internal attacks as well as prohibit unauthorized access to resources and systems housing critical data. SIEMs may harden endpoints, detect unusual data transfers, and secure data while it is in use, in motion, or at rest. Networks can be monitored by intrusion detection systems (IDSs) for known threats and erroneous or suspicious traffic. Email security tools with AI capabilities can detect social engineering attempts and thwart phishing emails before they reach employees.

• Phishing Prevention: A crucial first step in reducing the danger of data exfiltration is taking measures to stop phishing assaults. To this end, it's critical to inform staff members about how phishing attacks operate, how to recognize one, and what to do if they suspect they are being targeted. This kind of attack can be avoided by creating rules for security analytics tools that can send out alerts when they discover emails, SMS messages, and other information that may contain phishing scams.

  Best Practice

  Best option for blocking Phishing Attacks is using Zenarmor NGFW on your open source firewall, like OPNsense, pfSense software, Ubuntu, or CentOS. With the help of Advanced Security options on Zenarmor NGFW, you can prevent data exfiltration by stopping phishing attacks with just one click.

  Zenarmor NGFW allows you to easily upgrade your firewall to a Next Generation Firewall in seconds. NG Firewalls empower you to combat modern-day cyber-attacks that are becoming more sophisticated every day.

  Some of the capabilities are layer-7 application/user-aware blocking, granular filtering policies, commercial-grade web filtering utilizing cloud-delivered AI-based Threat Intelligence, parental controls, and the industry's best network analytics and reporting.

  Zenarmor Free Edition is available at no cost for all open-source firewall users.

• Risk Assessment: Risk assessments are used by organizations to determine which data is most sensitive, the biggest dangers to that data, the likelihood that those threats will materialize, and the harm that data exfiltration might result in. In this manner, they may most effectively prioritize, guard against, and get ready for those threats of data exfiltration.

  Organizations require thorough insight into the actions that call for security intervention as well as their data exposure. To completely assess potential risk, that entails closely monitoring PCs, cloud applications, and email providers.

• DLP: When data is transferred or stored in a way that could suggest exfiltration, data loss prevention (DLP) tools can notify your team. DLP warnings make it possible for the company to act quickly before lasting damage is done.

• EDR: Monitoring network endpoints for indications of malicious activity is made possible by endpoint detection and response, or EDR, software. In addition, they can use automated reactions based on pre-established playbooks as a speedy response to data exfiltration.

Can a Firewall Protect Your Data From Exfiltration?

Yes, firewalls can protect data. Nothing compares to the viability of a firewall when it comes to safeguarding the network, server, or website database from any unauthorized access or intrusion. Firewalls are useful to prevent any data incursion when used properly. Some technically competent firewalls can perfectly and easily protect networks against both internal and external threats. They provide a variety of security options, including SSL, VPN, proxy servers, IP monitoring, and many others. A sophisticated firewall can monitor traffic as well with broad traffic monitoring.

Firewalls can filter malicious outbound traffic. By doing this, it decreases the likelihood that a malicious insider will steal data without being caught, as well as the possibility that the devices protected by the firewall may join a botnet, a sizable network of internet-connected devices controlled by attackers for harmful objectives.

Best Practice

The Zenarmor Next-Generation Firewall is one of the most effective methods for preventing C2 assaults. In only seconds, Zenarmor enables you to upgrade your open-source firewall to a Next Generation Firewall. NG Firewalls enable you to resist the increasingly complex cyberattacks of the present day.

Layer-7 application/user-aware blocking, granular filtering rules, commercial-grade web filtering with cloud-delivered AI-based Threat Intelligence, parental controls, and the industry's finest network analytics and reporting are a few of the features.

Zenarmor Free Edition is accessible to all OPNsense users at no cost.

For businesses with networks made up of numerous internet-connected endpoints, firewalls are extremely useful. When a firewall is installed correctly at the network's edge, it creates a single point of entry where some incoming threats can be recognized and reduced.

Additionally, it offers a secure environment where data can flow more easily and securely by separating the company's internal systems from the open internet.

What are the Differences Between Data Exfiltration and Data Breach?

A data breach is any incident where sensitive data is exposed as a result of criminal behavior online. Data breaches can happen as a result of cyber attacks, on-the-job mistakes made by people who have worked for the company before, or unintentional data loss or exposure. Hackers or employees divulge or leak private information in a data breach. As a result, there is a chance that the data will be lost or misused by the offenders.

Closing the gaps is becoming a top goal for all firms because data breaches may have legal repercussions. It's critical to realize that data breaches can result from a variety of planned and unintentional internal business activities as well as attempts by external parties to obtain your data.

On the other hand, data exfiltration is known as theft, unauthorized removal, or movement of any data from a device. Data exfiltration typically involves a cybercriminal using various cyberattack techniques to steal data from private or corporate devices, like computers and mobile phones.

What are the Differences Between Data Exfiltration and Data Leakage?

Data leaks are any internal incidents that expose private information to an insecure setting without being a cyberattack. A data leakage is distinct from a data breach in that it is unknown whether the disclosure of this material is spread to a wider public. When personal information is exposed, it can happen in a number of ways, including when a user is given unauthorized access to a website, when your security procedures are flawed, or even when an application is created improperly. The fact that it stems from an internal source or a process defect is crucial in this situation.

When security precautions are not correctly applied while transmitting data, data leaks happen. If the proper safeguards are not in place, data that is not currently in use may leak.