The Data Exfiltration Techniques You Need to be Aware of

The nature of cybersecurity threats businesses face is evolving all the time. But in today’s environment, the biggest dangers often come when hackers are able to get their hands on a firm’s sensitive data and take it out of the company.

This is data exfiltration and it can be one of the most consequential issues for any enterprise. It can lead to the public exposure of trade secrets or customers’ personal and financial details. As well as the business and reputational damage this can create, it leaves companies exposed to the risk of multimillion-dollar fines for breaches of data protection laws.

Cybercriminals are well aware of the value of business data, and also know firms will often be prepared to pay large sums to avoid such public disclosures. This makes data exfiltration a highly lucrative activity for hackers. Once they have a business’ data, they have a wide range of options for how they can do damage – and it will be too late for firms to do anything about it.

As such, any cybersecurity strategy needs to have a specific plan in place to detect and block data exfiltration before it occurs. So how can these attacks harm your business and what should you be doing to prevent them?

Data exfiltration refers to any digital assets that are removed from your network environment with malicious intent. While data leakage can happen accidentally, deliberate data exfiltration may be much more damaging, as those responsible will already have a plan for how they can use it to harm a business or make money.

It’s important to understand that every business is a potential target of data exfiltration – even those that may not traditionally think of themselves as high risk. Firms that believe the data they hold is not valuable enough to be of interest to hackers, or that they are small enough to fly under the radar of cybercriminal groups, may be in for a nasty surprise.

In many cases, such firms make particularly tempting targets, and there are several reasons for this. For starters, they often have weaker defenses, so make for easier targets. Secondly, they may be more willing to make a ransomware payment as they cannot afford to ride out any disruption. 

They may also have working relationships with larger firms that can give hackers access to more valuable data. For example, a small IT contractor or managed service provider might hold login or personal data for partner businesses that hackers can use to launch larger attacks.

Aside from these issues, there are a few sectors that have proven to be particularly vulnerable to data exfiltration as part of ransomware attacks – and a common theme is they tend to hold especially valuable data, such as financial or medical records. For instance, BlackFog’s 2022 State of Ransomware report found the three sectors most likely to be targeted by cybercriminals are education, government and healthcare.

Once data has been exfiltrated from a business, cybercriminals have a range of options. For example, a malicious insider may try to take company secrets to a new employer or sell them to a competitor, while personal and financial details will be useful in identity theft. 

If customers do have their details used by fraudsters and can trace the source of the breach back to a company they had trusted with their information, the reputational damage can be immense, and many victims will refuse to do business with them again.

One of the most common next steps following a data exfiltration attack is for a ransom demand to be made. Hackers typically threaten to publicly release stolen data unless a payment is made, persuading firms to hand over money to avoid reputational damage. 

This can be highly lucrative to hackers. Figures from Titanium suggest 60 percent of firms that have data exfiltrated by hackers are subsequently extorted, and according to Statista, almost three-quarters of ransomware victims in 2022 (72 percent) paid up. As our own research shows the average ransomware payment reached $258,000 last year, it’s clear that falling victim to data exfiltration can prove very costly.

Once a ransomware attack has been completed and a demand for payment is made, it’s far too late for businesses to respond, so the best course of action is to prevent hackers from getting their hands on the sensitive data they need to extort firms with in the first place. 

This starts at the network edge, with advanced firewalls and intrusion detection systems to block hackers before they have a chance to cause a data breach. However, these aren’t infallible, and the advanced tactics used by many ransomware groups can allow them to bypass traditional perimeter defenses.

Therefore, defense in depth is a must. As we’ve seen, stealing data is now the ultimate goal for many hacking attempts. Specialized anti data exfiltration (ADX) solutions have a key role to play in this, as they ensure that even in a scenario where hackers gain access to your most valuable assets, they won’t be able to remove them from the business.

Data exfiltration comes in many forms. As well as the threat posed by hackers, you also need to consider the risks that originate within your business – both from careless users and malicious insiders. As a result, any data exfiltration prevention efforts must be able to cover a wide range of actions.

There are a variety of techniques that may be used for data exfiltration. These range from technical hacks to social engineering attacks, or even in some cases physically walking out of the door with your data. 

By familiarizing yourself with the various methods used, you can better formulate plans to stop them. Each will have its own demands, so there’s no such thing as a one-size-fits-all solution that applies to every scenario. Here are some key types to be aware of:

Social engineering – These try to trick unsuspecting employees into handing over business data, often using a phishing attack. This makes them appear to be trusted colleagues or executives and encourages people to attach data to outbound emails.

Insecure devices – Downloading data to insecure devices such as personally-owned smartphones is a common way for data exfiltration to occur, as these can be easily lost, stolen or compromised by malware once outside the business’ network.

Physical removal – Often used by malicious insiders, transferring information to a laptop or USB stick can allow them to easily exfiltrate data and bypass any network defenses. The loss or theft of devices such as laptops also falls under this category.

Network transfer – External hackers can use a variety of tools to send data back to their command and control servers using data transfer. Often packaged in formats that look legitimate, this can be amongst the hardest types of data exfiltration to detect and stop.

As is the case with many other cybersecurity threats, human error is the most common cause of data exfiltration. This can include employees falling victim to phishing attacks, either as an entry route for ransomware or by handing over data or login credentials directly. Other mistakes may include weak password practices or poorly-configured networks that can open up entry points for a threat actor.

Elsewhere, advanced persistent threats and zero-day vulnerabilities can also offer opportunities to hackers, which is why strong perimeter defenses, including firewalls, email security and intrusion detection software should all be part of a firm’s strategy.

However, tools cannot only look outwards. If this is the case, cybersecurity threats that are able to bypass the first line of defense will be able to move freely within a network to find the most valuable information and then exfiltrate data without detection.

Many of the tools used by hacking groups to exfiltrate data are hard for traditional cybersecurity solutions to detect as they often look very similar to innocent activity. For example, the use of web applications or cloud services may go unnoticed as it is not uncommon for employees to frequently connect and share data with web services outside of the network.

By establishing anonymous connections to third-party servers, hackers will be able to take all the time they need to exfiltrate data so as not to arouse suspicion. In many cases, firms may be unaware for weeks or even months that they have been compromised. 

There are a variety of options available to hackers for transmitting sensitive information back to command and control servers or other channels. These can include fileless attacks, direct IP address connections, HTTP tunneling and remote code execution.

An effective data exfiltration prevention strategy requires the use of dedicated tools that can go above and beyond the capabilities offered by traditional data security solutions such as anti-malware software. Having solutions specifically tailored for the enterprise ensures firms have the best level of protection against this growing threat.

Many of today’s more advanced data exfiltration threats, such as fileless attacks, lack the telltale signs that legacy tools look for. This makes them invisible to defenses such as antimalware when they are entering the business, and once inside, they can move around and exfiltrate data undetected. 

Traditional defenses such as signature matching, structured data fingerprinting and file tagging typically cannot distinguish between users or intent, meaning they are unable to separate legitimate traffic from unintentional errors or malicious action. The best way for businesses to spot data exfiltration is therefore to ensure they are looking at user behavior.

At a basic level, data exfiltration detection tools can examine factors such as the time of day a data transfer takes place, what its destination is – and if attempts are being made to disguise it – and the volume and type of data in motion, as well as whether this corresponds to a user’s normal activity and permitted access levels. If unusual behavior is detected, this can then be flagged immediately.

Understanding these patterns is the key to success in data loss prevention. A good solution should be able to do this at scale across all of a business’ endpoints and be ready to intervene without human input.

BlackFog’s ADX tools aim to prevent data exfiltration by monitoring all outgoing network traffic at the device level. Advanced machine learning tools can build up a complete picture of what normal business activity looks like in order to spot any unusual activity and block data transfers out of the business automatically, while reducing the risk of false positives that can disrupt innocent activity.

Because BlackFog’s ADX works at the endpoint, it is inherently more secure than more traditional tools, which may have to send encrypted data back to a central server and decrypt it for analysis before sending it on. This also makes the solution easier and less resource-intensive than traditional endpoint security solutions. 

It also requires far less management from a security team than other alternatives. Acting as a virtual CISO, it is able to shut down any data exfiltration attempts before damage can be done, offering peace of mind while also freeing up professionals from tedious admin activities.

Learn more about how BlackFog protects enterprises from the threats posed by data exfiltration.