FreeDrain Unmasked | Uncovering an Industrial-Scale Crypto Theft Network
Summary:
FreeDrain is a large-scale, sophisticated cryptocurrency phishing campaign that has operated for several years, silently stealing digital assets by exploiting weaknesses in free-tier web infrastructure, search engine optimization, and user trust in legitimate platforms. Discovered through joint research by SentinelLABS and Validin and unveiled at PIVOTcon, the campaign has leveraged over 38,000 distinct subdomains across free publishing platforms such as GitBook, Webflow, GitHub Pages, Teachable, and Weebly to host lure pages that imitate cryptocurrency wallet interfaces. These pages, often hosted on trusted domains, are indexed at the top of search engine results through SEO manipulation, spamdexing, and the use of AI-generated content designed to resemble helpful wallet management guidance.
The attack begins when victims search for common wallet-related queries like “check Trezor wallet balance” and unknowingly click on high-ranking lure pages. These pages typically feature a large, clickable image of a legitimate wallet interface and minimal text. Clicking the image initiates redirection through several intermediary domains, eventually leading to a phishing site that closely mimics the real wallet provider and prompts the user to enter their seed phrase. Once submitted, automated backend systems immediately drain the associated wallet. The infrastructure is designed to blend seamlessly into the web ecosystem by abusing the trust associated with recognizable hosting platforms, using content generation tools such as large language models, and rotating between live phishing pages and benign content to avoid detection.
The discovery of this campaign was triggered by a report to Validin in May 2024 from a victim who lost approximately 8 Bitcoin after visiting a malicious site listed prominently in a search engine result. This incident, paired with earlier research from April, revealed that FreeDrain’s method of delivery was not through traditional phishing vectors like email or SMS, but through highly-ranked search engine results. SentinelLABS and Validin developed custom tooling to monitor and track FreeDrain’s presence in search results using thousands of keyword permutations, ultimately collecting over 200,000 unique URLs and mapping the full extent of the campaign’s infrastructure and workflow.
Security Officer Comments:
The campaign’s infrastructure includes a network of redirector domains characterized by algorithmically generated names and GUID-based URL paths, often hosted via services like Amazon S3 and Azure Web Apps. These redirectors enable the seamless transition from benign lure content to active phishing pages, with redirect behavior often tailored by time of day, browser user agent, or region. In many cases, lure pages were initially benign and only later altered to include redirection scripts, a tactic that helps them evade early detection and gain credibility with search engine algorithms. The FreeDrain operation is believed to be operated by a coordinated team working standard weekday hours within the UTC+05:30 timezone, based on commit metadata from GitHub repositories and Webflow publish timestamps. Repository analysis revealed hundreds of unique email addresses tied to individual lure pages, most from free email providers, suggesting manual account creation and operational discipline. Furthermore, commit and publish patterns showed consistent behavior aligning with a standard workday schedule, with signs of coordinated content generation, staging, and deployment cycles.
Disruption of FreeDrain has been difficult due to the campaign’s abuse of dozens of free content platforms, most of which lack proactive abuse detection mechanisms and do not allow reporting directly from the hosted page. The platforms' failure to detect repeatable naming conventions, cloned templates, and infrastructure overlap has allowed FreeDrain to persist and scale. Many pages showed content artifacts referencing tools such as GPT-4o mini, indicating careless but automated use of generative AI for content creation.
Suggested Corrections:
Users should always be cautious of individuals or organizations that ask for personal information. Most companies will not ask for sensitive data from their customers. If in doubt, users should verify with the company itself to avoid any potential issues.
Users should always take a close look at the sender’s display name when checking the legitimacy of an email. Most companies use a single domain for their URLs and emails, so a message that originates from a different domain is a red flag.
As a general rule, users should not click links or download files even if they come from seemingly “trustworthy” sources.
Check for mismatched URLs. While an embedded URL might seem perfectly valid, hovering above it might show a different web address. In fact, users should avoid clicking links in emails unless they are certain that it is a legitimate link.
Users should always be on the lookout for any grammatical errors and spelling mistakes. Legitimate companies will often employ proofreaders and editors who ensure that the materials they send out are error-free.
Users should not be frightened or intimidated by messages that have an alarmist tone. They should double check with the company if they are uncertain about the status of their accounts.
Phishing emails are designed to be sent to a large number of people, so they need to be as impersonal as possible. Users should check whether the message contains a generic subject and greeting, as this can be a sign of a phishing attempt.
Although not every end user has access to advanced anti-phishing software, they can still use the built-in protection of their email clients to filter messages. One example is setting the email client to block all images unless approved.
Legitimate companies will never send confirmation emails unless there are specific reasons for doing so. In fact, most companies will avoid sending unsolicited messages unless it’s for company updates, newsletters, or advertising purposes.
Users should always take the context of an email or message into account. For example, most online accounts do away with viewable member numbers, so users should be wary if they receive emails containing a “member number” for services that generally don’t use them.
It is important to take note of unusual information in the text of the message. Any mentions of operating systems and software that are not typically used by consumers can often be indicators of a phishing attempt.
If it seems suspicious, it probably is. Users should always err on the side of caution when it comes to sending out personally identifiable information through messages and emails.
Link(s):
https://www.sentinelone.com/labs/fr...ing-an-industrial-scale-crypto-theft-network/
FreeDrain is a large-scale, sophisticated cryptocurrency phishing campaign that has operated for several years, silently stealing digital assets by exploiting weaknesses in free-tier web infrastructure, search engine optimization, and user trust in legitimate platforms. Discovered through joint research by SentinelLABS and Validin and unveiled at PIVOTcon, the campaign has leveraged over 38,000 distinct subdomains across free publishing platforms such as GitBook, Webflow, GitHub Pages, Teachable, and Weebly to host lure pages that imitate cryptocurrency wallet interfaces. These pages, often hosted on trusted domains, are indexed at the top of search engine results through SEO manipulation, spamdexing, and the use of AI-generated content designed to resemble helpful wallet management guidance.
The attack begins when victims search for common wallet-related queries like “check Trezor wallet balance” and unknowingly click on high-ranking lure pages. These pages typically feature a large, clickable image of a legitimate wallet interface and minimal text. Clicking the image initiates redirection through several intermediary domains, eventually leading to a phishing site that closely mimics the real wallet provider and prompts the user to enter their seed phrase. Once submitted, automated backend systems immediately drain the associated wallet. The infrastructure is designed to blend seamlessly into the web ecosystem by abusing the trust associated with recognizable hosting platforms, using content generation tools such as large language models, and rotating between live phishing pages and benign content to avoid detection.
The discovery of this campaign was triggered by a report to Validin in May 2024 from a victim who lost approximately 8 Bitcoin after visiting a malicious site listed prominently in a search engine result. This incident, paired with earlier research from April, revealed that FreeDrain’s method of delivery was not through traditional phishing vectors like email or SMS, but through highly-ranked search engine results. SentinelLABS and Validin developed custom tooling to monitor and track FreeDrain’s presence in search results using thousands of keyword permutations, ultimately collecting over 200,000 unique URLs and mapping the full extent of the campaign’s infrastructure and workflow.
Security Officer Comments:
The campaign’s infrastructure includes a network of redirector domains characterized by algorithmically generated names and GUID-based URL paths, often hosted via services like Amazon S3 and Azure Web Apps. These redirectors enable the seamless transition from benign lure content to active phishing pages, with redirect behavior often tailored by time of day, browser user agent, or region. In many cases, lure pages were initially benign and only later altered to include redirection scripts, a tactic that helps them evade early detection and gain credibility with search engine algorithms. The FreeDrain operation is believed to be operated by a coordinated team working standard weekday hours within the UTC+05:30 timezone, based on commit metadata from GitHub repositories and Webflow publish timestamps. Repository analysis revealed hundreds of unique email addresses tied to individual lure pages, most from free email providers, suggesting manual account creation and operational discipline. Furthermore, commit and publish patterns showed consistent behavior aligning with a standard workday schedule, with signs of coordinated content generation, staging, and deployment cycles.
Disruption of FreeDrain has been difficult due to the campaign’s abuse of dozens of free content platforms, most of which lack proactive abuse detection mechanisms and do not allow reporting directly from the hosted page. The platforms' failure to detect repeatable naming conventions, cloned templates, and infrastructure overlap has allowed FreeDrain to persist and scale. Many pages showed content artifacts referencing tools such as GPT-4o mini, indicating careless but automated use of generative AI for content creation.
Suggested Corrections:
Users should always be cautious of individuals or organizations that ask for personal information. Most companies will not ask for sensitive data from their customers. If in doubt, users should verify with the company itself to avoid any potential issues.
Users should always take a close look at the sender’s display name when checking the legitimacy of an email. Most companies use a single domain for their URLs and emails, so a message that originates from a different domain is a red flag.
As a general rule, users should not click links or download files even if they come from seemingly “trustworthy” sources.
Check for mismatched URLs. While an embedded URL might seem perfectly valid, hovering above it might show a different web address. In fact, users should avoid clicking links in emails unless they are certain that it is a legitimate link.
Users should always be on the lookout for any grammatical errors and spelling mistakes. Legitimate companies will often employ proofreaders and editors who ensure that the materials they send out are error-free.
Users should not be frightened or intimidated by messages that have an alarmist tone. They should double check with the company if they are uncertain about the status of their accounts.
Phishing emails are designed to be sent to a large number of people, so they need to be as impersonal as possible. Users should check whether the message contains a generic subject and greeting, as this can be a sign of a phishing attempt.
Although not every end user has access to advanced anti-phishing software, they can still use the built-in protection of their email clients to filter messages. One example is setting the email client to block all images unless approved.
Legitimate companies will never send confirmation emails unless there are specific reasons for doing so. In fact, most companies will avoid sending unsolicited messages unless it’s for company updates, newsletters, or advertising purposes.
Users should always take the context of an email or message into account. For example, most online accounts do away with viewable member numbers, so users should be wary if they receive emails containing a “member number” for services that generally don’t use them.
It is important to take note of unusual information in the text of the message. Any mentions of operating systems and software that are not typically used by consumers can often be indicators of a phishing attempt.
If it seems suspicious, it probably is. Users should always err on the side of caution when it comes to sending out personally identifiable information through messages and emails.
Link(s):
https://www.sentinelone.com/labs/fr...ing-an-industrial-scale-crypto-theft-network/