How to Check if Your Data is on the Dark Web

In this blog we discuss how data can end up on the dark web and how businesses can use dark web monitoring to prevent this.

How does your data end up on the dark web?

Unlike the side of the internet that most people have access to, the dark web is purposely hidden to avoid scrutiny by law enforcement, governments or other organizations. The dark web is made up of sites such as marketplaces that sell and trade illicit products, ransomware leak sites where gangs share details of their latest victims, and forums that discuss and organize criminal activity.

Behind most cyberattacks is the motive of financial gain, which is where the exploitation of personal and business data comes from. For example, cybercriminals can sell data and information on the dark web, use it to commit further attacks, engage in identity theft, or access bank account and credit card information.

On the dark web data is a hot commodity, but how does it end up on marketplaces to begin with?

If an organization has vulnerabilities, whether that be due to human error or within their technology infrastructure, cybercriminals will look to exploit those vulnerabilities. A data breach can come in many forms including:

Phishing attacks

‍Phishing is when cybercriminals send scam emails to unsuspecting victims that ask for sensitive information or login credentials to be supplied. The email will look as though it has come from a trusted source and will require urgency, pushing the email recipient into taking quick action that leads them to misjudge the authenticity of the message. The phishing email may also result in the recipient downloading software that is malicious, which when executed could exfiltrate data from their computer or the wider organizations server.

Ransomware attacks

‍Ransomware is used by cybercriminals to encrypt a user’s data, with the ransomware gang following up the attack with demands for payment in order to restore access. If a ransom isn’t paid, the gang will then go on to trade or sell the data on dark web marketplaces to other cybercriminals who will further exploit the initial vulnerabilities using the likes of log in credentials or financial information.

Insider threats

‍As the name suggests, insider threats are attacks that come from within an organization. The likes of disgruntled employees that have access to sensitive information may download this data and trade it on the dark web for financial remuneration. Insider threats may also come from employees that have been approached by cybercriminals on the dark web with a request for particular data.

Third-party data leaks

‍A 2024 report from Verizon found that third-parties influenced 15 percent of the breaches, compared with 9 percent in 2023. The report highlights the need for organizations to be more aware of third-party risks and have better knowledge of the vulnerabilities associated with these types of attacks.

Supply chain attacks can result in a cybercriminal harvesting a lot of data that spans hundreds of different organizations, which makes this type of attack popular. While gaining access to an organization’s supply chain may take time, once they’ve done it all of the data they’ve collected will then go on to be sold or traded on dark web marketplaces where it can be used for exploitation. And, if an organization’s supplier doesn’t make them aware a breach has happened, they will be none the wiser if they have been compromised and at risk of further cyberattacks.

Monitoring for information exposure

If an organization suspects a data leak has happened, it can be hard to know where to start to identify if it has made its way onto the dark web.

Not only is the dark web inaccessible through traditional search engines, it is unindexed unlike websites on the clear web. This makes the task of finding data on the dark web a lot harder. But, dark web monitoring tools, like the one from Searchlight Cyber, can make the task of tracking data breaches easier and more efficient.

Asset discovery

The first step for organizations using dark web monitoring tools should be asset discovery. If security teams are only managing and tracking the assets they know about, other assets being used by employees in the organizations may go unpatched, be unsecured, or wrongly have access to sensitive data.

Searchlight Cyber’s tool gives security teams full visibility and a clear picture of all the applications, websites, networks, devices, and cloud infrastructure that could potentially be vulnerable to attack. With asset discovery the organizations can have peace of mind they are protecting all of their assets and mitigating the risk of a cyberattack.

Monitor assets

The next stage is the continuous dark web monitoring to help secure those assets. Modern environments have a steady flow of changes and updates, which is why dark web monitoring is needed to keep up. Dark web monitoring tools will automatically scan the dark web to detect and monitor potential threats and vulnerabilities that can compromise an organization's assets. Being able to monitor and identify if IP addresses, email credentials, domains, and software are being mentioned on the dark web gives organizations the actionable insights they need to ensure their security posture reflects current and potential threats.

Dark web data coverage

When monitoring the dark web for threats organizations will be relying on the breadth and depth of data available to them. Organizations must use a solution that not only has historical and archived data from the dark web, but is also continuously updated and adding new marketplaces, forums, and leak sites. This means that as the dark web evolves, businesses have full visibility of the threats relating to them.

What Are the Risks of Having Data Exposed on the Dark Web?

There’s no doubt that if an organization’s data does end up on the dark web the likelihood of additional cyberattacks and threats rise.

In a recent study Searchlight Cyber and Marsh McLennan explored this correlation and confirmed mentions of an organization of the dark web increased the chance of a cyber incident.

The key findings from the report were that the likelihood of a cyber incident increased if an organization was mentioned in any of these dark web sources:

• Compromised data - 2.56x.
• Dark web market listing - 2.41x.
• Outgoing dark web traffic - 2.11x.
• OSINT results - 2.05x.
• Paste results - 1.88x.
• Telegram chats - 1.75x.
• Incoming dark web traffic - 1.63x.
• Forum posts - 1.58x.
• Dark web pages - 1.29x.

This study highlights the importance of asset discovery, continuous dark web monitoring, and the depth of data needed to ensure all dark web risks are mitigated. If an organization is missing sources there may be threats that they are unaware of and they will also have a less reliable view of their cybersecurity risk.

Cybersecurity teams need to establish that they have coverage of all areas of the dark web - marketplaces, forums, paste sites, Telegram channels, and dark web sites, and monitor for particular signals that could indicate an impending cybersecurity attack. For example, knowing that a cybercriminal is discussing an organization on a dark web forum is not enough. Cybersecurity teams need sources that provide them the intelligence on the forum, the cybercriminal that has made the post, and what exactly the cybercriminal has posted about them in order to establish what action they need to take next.

How Can You Check If Your Data Is on the Dark Web?

There are two ways to check: a one-time scan and ongoing dark web monitoring.

A one-time scan searches known breach databases and dark web sources for specific identifiers, such as an email address, domain or set of credentials, and tells you whether they appear at that moment. It is useful for a quick check after a suspected breach, but it only shows a snapshot. Data that is leaked or sold tomorrow won't appear in today's results.

Continuous dark web monitoring automatically and repeatedly scans marketplaces, forums, paste sites, Telegram channels and ransomware leak sites for your organization's identifiers, then alerts you when something new appears. For organizations, this is the more reliable approach, because exposure is not a one-off event and stolen data can surface weeks or months after the original breach.

Because the dark web is not indexed by search engines, you cannot reliably check it by searching manually. Accessing criminal sites directly also carries security and legal risks. Most organizations use a monitoring tool that has already collected and indexed dark web data, so they can search it safely.

What Does a Dark Web Monitoring Alert Tell You?

A match or no-match notification is not enough to act on. A useful alert provides context that lets a security team decide what to do next:

• What was exposed: The specific identifier that matched, such as an email address, credential pair, domain, IP address, or employee or customer record.
• Where it was found: The type and name of the source, for example a marketplace listing, a hacking forum post, a stealer-log dump, a Telegram channel or a ransomware leak site.
• What type of data was involved: Credentials, personal data, financial information, internal documents or source code.
• When it appeared: The date of the listing or post, which helps you work out whether it relates to a known incident or is new.
• Who is behind it: Where available, details about the actor or group that posted it and their history.

Alerts with this context are much faster to triage than bare notifications, and they reduce the time between detection and action. They also make it easier to separate genuine threats from noise, such as recycled data from old breaches.

Dark Web Exposure Response Workflow

1. Detect: Identify that an organization's data, credentials or assets have appeared on the dark web, ideally through continuous monitoring rather than discovery by a third party.
2. Validate: Confirm the exposure is genuine and relevant. Check whether the data matches your systems, whether it is current or recycled from an older breach, and whether it came from your organization or a third party.
3. Assess: Judge the severity. Consider what was exposed, how sensitive it is, whether it is being sold or only mentioned, and what an attacker could do with it, such as account takeover, fraud or a follow-on attack.
4. Remediate: Act on the findings. Reset exposed credentials, revoke sessions and tokens, enforce multi-factor authentication, close the access route, notify affected parties and meet any regulatory obligations.
5. Monitor: Keep watching for further activity, such as resale, republication or reuse of the same data, and feed what you learn back into your defenses.

What Should You Do If Your Data Is Found on the Dark Web?

If your organization’s data is found on the dark web, confirm the exposure is genuine, contain any active risk such as stolen credentials or access, investigate how the data got there, and fix the cause. 

Actions by type of exposure:

Employee credentials: Force password resets for the affected accounts and for any others where the same password may have been used. Revoke active sessions and tokens, confirm mFA is enforced, and review recent sign-in activity for unfamiliar locations, devices or access times.

Customer and user credentials: Reset or lock the affected accounts, force re-authentication, and watch for credential stuffing and account takeover attempts against your login pages. 

Customer, employee or other personal data: Work with legal and privacy teams to establish what data was involved, whose it is, and which breach notification laws, regulators and contractual obligations apply, since many have strict deadlines.

Source code and internal documents: Rotate any API keys, tokens, certificates and passwords found in the exposed material, review repositories and build systems for unauthorized access, and assess the commercial security of this impact.

Access being sold or advertised: Treat it as a possible active intrusion. Disable the access path, hunt for related activity in your logs and bring in incident response.

Third party or supplier exposure: Contact the supplier, review and restrict the access they have to your systems, change any shared credentials.

Steps for any exposure:

1. Validate before escalating: Check whether the data matches your systems, whether it’s current or recycled from an older breach, and whether it originated with your organization or a third party.
2. Preserve evidence: Keep the alert, any samples, logs and timelines before systems are changed, so the investigation and any legal or regulatory process have a record.
3. Contain: Limit what an attacker can do with what was exposed, through resets, revocation, account restrictions and blocking.
4. Investigate the source code

How Can Businesses Reduce Dark Web Data Exposure?

With Searchlight Cyber’s dark web monitoring tools, you can automatically monitor for external threats to your digital environments and prevent your sensitive information ending up on the dark web. Dark web monitoring allows you to find indicators of a data breach and can take any business from being cyber reactive to cyber progressive. Doing this gives you the invaluable insight you need to change and update your infrastructure as you see potential breaches appearing.