Stealer logs detection for a company starts with a domain-level lookup, not a single mailbox. We ran the free options we could reach from a script on 1 November 2026, using brandefense.io and one test mailbox that belongs to nobody. Two options ran without a key or sign-in. The rest needed ownership proof, a key or a bot check, or no longer exist.
What We Tested and How
An infostealer is malware that copies saved logins, cookies and session tokens from an infected device. The copied data is called a stealer log, and it is traded in bulk. Our stealer logs glossary entry explains the format.
Each option we could run got the same two inputs: our own domain and a mailbox on that domain that nobody uses. We saved every raw response. We show counts only, never a login, address or device detail, and the report names no tool as better than another.
Free Options Compared on the Same Inputs
| Option. | Domain lookup. | Email lookup. | What it needs. |
|---|---|---|---|
| Hudson Rock free API. | Returned counts for brandefense.io. | Returned a yes or no style message. | No key or sign-in for these two calls. |
| LeakCheck public API. | Answered “Not found” (domain search is not offered on the public API). | Answered “Not found”. | No key; one request per second. |
| Atlas breach monitoring (Brandefense). | Counts for a company domain, entered by a person in the browser. Not run from a script. | Not offered; free webmail is not supported. | A corporate domain typed into the form. The form has a Cloudflare Turnstile bot-check slot. |
Hudson Rock and LeakCheck ran from a script, and only Hudson Rock said anything about a company. Atlas also works at domain level but needs a person in a browser. Have I Been Pwned and Google’s retired report are covered in the part on what we could not run.
Hudson Rock: Counts for a Domain
Hudson Rock offers free lookups. Its domain call for brandefense.io returned a report with 5 credential records. Of these, 0 were employee records, 4 were customer-side records and 1 came from a third-party service.
The same response carried a global totalStealers figure of 37,181,889 in the Hudson Rock dataset. That number describes their whole collection, not our company. The most recent customer-side record was dated 2 September 2025.
The email call is less useful for a company. For our test mailbox it answered that the address “is not associated with a computer infected by an info-stealer”. A dummy address was never going to match, so a negative answer proves little. A real check needs the domain view.
Atlas: Free Domain-Level Breach and Stealer Log Check
Atlas is the free tool set from Brandefense, and its breach monitoring page works at domain level. You type a corporate domain such as company.com; free webmail is not supported. The report counts breaches, combolists, stealer logs, infected devices, data-sale listings and exposed documents.
The dashboard shows the counts, the trend over the last month, quarter and year, and masked samples of where the exposure came from. It never shows usernames, passwords, addresses or IPs. Anything not shown for free stays locked, and the page says full detail is shared with a verified contact in a short call.
The form has a Cloudflare Turnstile bot-check slot, so we did not run it from a script and report no result numbers for it. A person runs it in the browser, and the page says the check only reads the Brandefense database and alerts no one. Check your company domain on Atlas breach monitoring.
LeakCheck: A Source List, Not a Verdict
LeakCheck documents a public API that needs no key. According to its documentation it returns only the list of breach sources and the categories of exposed data, never the data itself. The page does not say whether the public API covers stealer logs.
Both of our calls came back with success: false and the error “Not found”. LeakCheck’s documentation lists domain search as unavailable on the public API, so the domain call was not a supported lookup. Treat this option as a quick single-address check.
What We Could Not Run
Have I Been Pwned holds stealer-log datasets. Its public breach list includes at least six stealer-log collections, from 26M email addresses in TelegramStealerLogs to 284M in AlienStealerLogs.
Searching a whole domain is another matter. HIBP says it allows this only after verifying that you are authorized to access assets on the domain, and larger domains normally need a subscription. Its API refused our test call with a 401 for a missing key.
Google retired its dark web report. Per Google, scans for new breaches stopped on 15 January 2026 and the report became unavailable on 16 February 2026. Our own Google dark web report alternatives post covers what to use instead.
How to Read the Results and What to Do Next
Match the lookup to the question. A single mailbox answers whether one person was hit. A domain count tells you whether staff or customers carry infections, which is the question that leads to action.
- Run a domain lookup first and note the date, because new logs land daily.
- Treat an employee-side record as an infected device, not only a leaked password. Resetting the password does not clean the machine.
- Separate employee records from customer-side ones. They need different responses.
- Follow the steps in our guide on how to respond to infostealer log exposure.
Free lookups are snapshots of what a provider happens to hold. For a free domain check in the browser, use Atlas breach monitoring. For continuous coverage across stealer logs, combolists and forums, see leaked credential monitoring. For how these logs turn into account takeovers, read our account takeover lifecycle analysis.