MyRecon OSINT
Prosper
On 1 September 2025, Prosper was breached. 17,605,276 accounts were exposed, including browser user agent details, credit status information, dates of birth. MyRecon rates it 74/100, severe. That is about 65% of the population of Australia.
Read the accompanying statement carefully: no evidence of unauthorised access to customer accounts. That can be entirely true at the same moment that 17.6 million people's Social Security numbers, incomes, employment status and credit standing have left the building. Account access and data theft are two different claims, and only one of them was being answered.
A lending platform holds the most complete financial identity most people ever assemble in one place, and it holds it for applicants as well as customers. People who were declined, or who filled in the form and thought better of it, have no account, no login, no dashboard and no particular reason to have been watching for a notice. They are in the file all the same.
This is one of the few entries in this archive where the usual advice is insufficient. A government identifier cannot be reissued because it leaked, so the only durable control is limiting what can be opened in your name. A credit freeze at each bureau is free, takes a few minutes, and lifts again when you actually need credit. It is the specific countermeasure for the specific data that left here, and it works whether or not anyone ever touches your Prosper account.
What happened
In September 2025, Prosper announced that it had detected unauthorised access to their systems, which resulted in the exposure of customer and applicant information. The data breach impacted 17.6M unique email addresses, along with other customer information, including US Social Security numbers. Prosper advised that they did not find any evidence of unauthorised access to customer accounts and funds, and that their customer-facing operations were uninterrupted. Further information about the incident is contained in Prosper's FAQs.
Breach description from Have I Been Pwned, used under a CC BY 4.0 licence. Data provided to HIBP by Hiron.
Read the original disclosure ↗
Who was behind it
No party has been publicly confirmed as responsible, and this page will not name one. Most breaches are never formally attributed: data surfaces on a forum or inside a combined dump long after the intrusion, and the trail back to a specific actor is rarely made public. Where a group has claimed responsibility it is usually named in the account above, that claim is theirs, not a finding of ours.
What was exposed, and why it matters
- Browser user agent detailsAdds detail to a profile that can be assembled from several breaches at once.
- Credit status informationAdds detail to a profile that can be assembled from several breaches at once.
- Dates of birthOne of the three things call centres ask to verify identity, and it never changes.
- Email addressesThe address becomes a confirmed, active target, expect more phishing, better aimed.
- Employment statusesAdds detail to a profile that can be assembled from several breaches at once.
- Government issued IDsPassport and licence numbers are used to prove identity to banks and telecoms, and they are effectively permanent.
- Income levelsAdds detail to a profile that can be assembled from several breaches at once.
- IP addressesApproximate location at the time of use, and a way to correlate accounts across services.
- NamesTurns an anonymous address into an identified person, which is what makes targeted phishing possible.
- Physical addressesWhere someone actually lives. Combined with a name this moves the risk off the internet.
What to do if you were in it
- Consider a credit freeze. A government identifier cannot be changed, so limiting what can be opened in your name is the only real control.
- Be sceptical of post and callers who already know your address, knowing it is no longer evidence of anything.
- Expect better-aimed phishing. A message that already knows your name and where you have an account is the whole point of a breach like this.
Questions people ask about this breach
Was my email address in the Prosper breach?
Enter it in the box at the top of this page. MyRecon checks it against this breach and every other one on record, and the address is never stored.
What data was leaked in the Prosper breach?
browser user agent details, credit status information, dates of birth, email addresses, employment statuses, government issued ids, income levels, ip addresses, names, physical addresses. Each one is explained above, along with what it means for the person it belongs to.
When did it happen, and when did it become public?
The breach is dated 1 September 2025. It was published to Have I Been Pwned on 16 October 2025, a gap of 45 days during which the data was already out.
Is the Prosper breach real?
Yes. Have I Been Pwned lists it as verified, meaning the data was checked against the source rather than taken on trust.
How many people were affected?
17,605,276 accounts. That is about 65% of the population of Australia. That is accounts rather than people, one person often has several.
Read next
Also in the archive
Case Files: how the landmark breaches actually happened →
Three kinds of content appear on this page and they are kept apart deliberately. The breach description is quoted from Have I Been Pwned under its licence. The severity score, the field-by-field explanation and the advice are computed from the record itself, every sentence derives from a number or a flag in it, which is what stops the analysis drifting from the evidence. Anything under the "MyRecon's take" byline is editorial: our reading of this breach, presented as opinion rather than as a finding.