Bithumb data leak exposes 844 customers: don't answer "staff" asking for codes
An intrusion into an internal work messaging system at crypto exchange Bithumb exposed personal data of 844 customers. Some records included ID card copies and bank account numbers, so be especially wary of calls or texts pretending to be Bithumb staff or authorities.
## What happened Bithumb says an outsider accessed its internal mobile groupware, Daou Office, between 11:28 a.m. and 12:27 p.m. on October 27 and took data out. The company noticed the abnormal access at 12:14 p.m., blocked the route and stopped using the system. [Bithumb official notice (Korean)](https://feed.bithumb.com/notice/1655458)
The leaked files covered 6,444 customers. According to the company, data for 5,600 of them was in encrypted files that cannot be read, while information on 844 customers was actually exposed. Data on 715 employees and contractor staff also leaked.
## What information was involved Items listed by the company include name, mobile number, email, date of birth, resident registration number, passport number, driver's license number, alien registration number, bank account number, address, ID card copy, transaction history and wallet address. The exact items differ from person to person.
According to Bithumb, the compromised tool is used only by staff and runs apart from exchange accounts and asset records. The company says it has found no trace so far of the attack reaching its trading service or customer DB. The cause is still under investigation.
## Check whether you are affected Bithumb is notifying affected customers individually by text and email, with the leaked items and what to do. Even without a message, you can check yourself with the "personal data leak lookup" button at the bottom of Bithumb's notice. [Bithumb notice with the leak lookup (Korean)](https://feed.bithumb.com/notice/1655458)
## Hang up on these requests Bithumb warns that the leaked data could be misused for identity theft, voice phishing and impersonation of Bithumb staff. The company says it never asks for passwords or verification codes by phone, text or messenger. Refuse any request to share a password, verification code or OTP, to disable or reset OTP, to install an unknown app or allow remote control, to transfer assets or change a withdrawal address, or to open a suspicious link.
If a contact feels off, stop right away and check through the customer center listed in Bithumb's official app or website (1661-5566, 24 hours). If money may be at risk, report it to the police at 112. It is also a good time to review your account's two-step verification.
## If your ID card copy leaked Customers whose ID copies were exposed will get separate instructions from Bithumb on getting a new ID or reporting it lost, services that block misuse of their identity, and ways to watch their accounts for unusual activity. Act on that guidance promptly.
## Where to report and get help Bithumb says it will provide relief and compensation for damage confirmed from this incident. Besides the company's line, you can seek advice or mediation from the Personal Information Infringement Report Center (118, no area code) and the Personal Information Dispute Mediation Committee (1833-6972). [Personal Information Infringement Report Center (Korean)](https://privacy.kisa.or.kr) [Personal Information Dispute Mediation Committee (Korean)](https://www.kopico.go.kr)
The Financial Services Commission held an emergency meeting on October 28 and began on-site inspections with the Financial Supervisory Service and the Financial Security Institute. It says it will make sure protections such as full compensation are provided if damage occurs. [Financial Services Commission press release (Korean)](https://www.fsc.go.kr/no010101/88010)
The illustrations and video are creative works made to aid explanation.
Written based on official notices and public information.
- 확인일
- 2026-10-30