GMO Internet Group data breach: what happened and what to do
Last reviewed October 29, 2026 · 2 records on file · sources listed below
GMO Internet Group is offering a reward for information leading to the arrest of attackers who breached its Onamae.com Desktop Cloud service, exposing customer data and leading to unauthorized FX trades.
If you have an account with GMO Internet Group, assume the exposed details are circulating. The practical risk today is rarely the leak itself — it is the calls and messages that use those details to sound legitimate.
What we have on file
Every entry below is a catalogued record with its original source. We do not paraphrase beyond what the source reports.
Personal Information · Ransomware
GMO Group, a Japanese internet giant, experienced a cyberattack involving ransomware, leading them to advise customers to disconnect their PCs and back up data.
What to do
- Change the password anywhere you reused itThe exposure matters most when the same password protects your email, because email is how everything else gets reset.
- Treat every call and text about this breach as a scam until proven otherwiseNo company will ask you for a one-time code, a PIN or a password. Hang up and call the number printed on your card.
- Read your statements for the next three monthsCard fraud usually starts with a small test charge. Catching that one is what stops the large one.
- Give your email account a password nothing else usesIt is the account that can reset all the others, so it is the one worth protecting first.
Questions people ask
Was my data in the GMO Internet Group breach?
Having an account alone does not confirm exposure. The reliable check is whether your email address appears in the leaked datasets in circulation — that takes seconds and does not require your password.
Is it too late to do anything?
No. Leaked personal details do not expire, and neither does the defence: a unique password on your email, and a fraud alert on your credit file, still work years later.
Will GMO Internet Group contact me?
They may. But scammers contact people too, using exactly these breach details to sound convincing. Never act on an inbound call or text — call back on a number you already had.
774 organisations catalogued
Records are catalogued from public reporting and linked to their original source. iTellYou is not affiliated with the organisations listed. If you represent one of them and something here is inaccurate, write to us and we will correct it.