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Data breaches → Bitcoin Talk

Was your data in the Bitcoin Talk breach?

2015 · bitcointalk.org · ~501,407 accounts exposedCritical severity · 10/10

Bitcoin Talk (bitcointalk.org) suffered a data breach in 2015 that exposed around 501,407 accounts. If you had an account, some of your personal data may be circulating in leaked databases. The fastest way to know is to check your own email — free, in about 30 seconds, no password required.

What happened

In May 2015, the Bitcoin forum Bitcoin Talk was hacked and over 500k unique email addresses were exposed. The attack led to the exposure of a raft of personal data including usernames, email and IP addresses, genders, birth dates, security questions and MD5 hashes of their answers plus hashes of the passwords themselves.

Breach details sourced from Have I Been Pwned, the industry-standard breach database. Risk analysis by Nullivo.

What was exposed, and why it matters

Not all breaches carry the same risk — what matters is which fields leaked. Here is what the Bitcoin Talk breach exposed and what each item actually enables:

Passwords

Attackers replay leaked passwords across other sites (“credential stuffing”). Because most people reuse passwords, one leak often unlocks email, shopping and banking accounts elsewhere.

Security questions and answers

Account-recovery answers let an attacker reset your password without ever knowing it — bypassing an otherwise strong password.

Dates of birth

Date of birth is a permanent identifier used to verify identity by phone. Combined with a name and address it is often enough to impersonate you.

Names and usernames

Links this leak to your other accounts — a reused username lets anyone build a profile of you across platforms.

Email addresses

Puts you on spam and phishing lists, and confirms to attackers that you hold an account with this service — which makes impersonation emails more believable.

IP addresses

Reveals your approximate location and internet provider, which adds credibility to targeted scams.

Also listed in this breach: Dates of birth, Email addresses, Genders, IP addresses, Passwords, Security questions and answers, Usernames, Website activity.

What to do if you were affected

These steps are ordered for this specific breach — the most urgent action given what leaked comes first.

  1. Passwords: Change this password everywhere you have reused it, starting with your email account — whoever controls your email can reset everything else.
  2. Security questions and answers: Change the answers on every account using them, and treat the answers as passwords (random strings stored in a password manager).
  3. Dates of birth: Never confirm your date of birth to an inbound caller — hang up and dial the organisation back on a published number.
  4. Names and usernames: Search your usual username to see what else it exposes, and use distinct handles for sensitive accounts.
  5. Email addresses: Treat any message referencing this service with suspicion, and never act on links in unexpected emails.
  6. Check whether your own email appears in this breach — run a free scan to confirm before you spend time on the steps above.

How urgent is this now?

This breach is over 11 years old. Old credentials still cause harm — leaked passwords from a decade ago are still tried against new accounts every day.

Passwords are the reason breach age matters less than people expect. Leaked credentials are compiled into wordlists that get tried against new services for years afterwards, so a password exposed here is unsafe to use anywhere, ever again.

Remember: a breach can't be "un-leaked" — once a database is out, it exists in countless copies. The goal is to make the leaked data useless: change what can be changed, lock down what can't, and remove what has been republished.

Check if your email was exposed.Nullivo's free scan checks your own verified email against known breaches — including Bitcoin Talk — in 30 seconds. No password, no signup, and we only ever scan your own email. Run your free scan →

Frequently asked questions

What data was exposed in the Bitcoin Talk breach?

The Bitcoin Talk breach exposed passwords, security questions and answers, dates of birth, names and usernames, email addresses, ip addresses. Attackers replay leaked passwords across other sites (“credential stuffing”). Because most people reuse passwords, one leak often unlocks email, shopping and banking accounts elsewhere.

How many people were affected by the Bitcoin Talk breach?

Around 501,407 accounts were exposed, making it a mid-sized breach.

What should I do if I had a Bitcoin Talk account?

Change this password everywhere you have reused it, starting with your email account — whoever controls your email can reset everything else. You can check whether your own email appears in this breach with a free Nullivo scan — no password required.

Breaches that exposed similar data

If the Bitcoin Talk breach affected you, these breaches exposed comparable information — worth checking too, since leaked datasets are routinely combined.

See all breaches we cover →