On October 17, the Bank of Thailand (BOT) and the Thai Bankers Association clarified the issue of unusual transactions occurring through credit and debit cards for numerous customers, stating that these incidents did not arise from data breaches within the banking system. The primary cause was identified as criminals randomly obtaining card information and using it to make transactions through foreign online merchants that do not utilize One Time Passwords (OTP). Since the beginning of October, there have been 10,700 cards reported with unusual usage due to this issue, with a significant number of transactions occurring over the past weekend primarily involving debit cards. Most of these transactions were for low amounts, such as $1, and were made multiple times. Banks have systems in place to detect unusual transactions, with each bank setting different thresholds and usage conditions based on the type of merchant and product.

Additionally, the BOT and the Thai Bankers Association have jointly established further measures to prevent and address the problem as follows:
1. Enhance the intensity of detecting unusual transactions to cover both low-value and high-frequency transactions. If unusual transactions are detected, banks will immediately suspend card usage and notify customers through all channels, including special monitoring of foreign transactions.
2. Increase customer notifications for all transactions starting from the first transaction through various channels such as mobile banking, email, or SMS.
3. In cases where customers are found to be affected by the aforementioned fraud, for debit cards, customers will receive refunds within 5 business days. For credit cards, the bank will cancel the disputed transactions, and customers will not be required to pay the irregular charges, with no interest accrued.
4. The BOT and the Thai Bankers Association will expedite discussions with card network providers such as Visa and Mastercard to implement additional identity verification measures, such as OTP for debit cards used in online transactions.

If customers notice any unusual transactions themselves, they can contact the call center or the issuing bank's branch to report and verify the accuracy of the transactions immediately. The bank will address and resolve any issues as quickly as possible.

For the general public, it is advisable to regularly check their transaction history and be cautious when linking debit cards for transactions, especially on high-risk platforms such as online games or platforms that do not require identity verification or OTP. Additionally, for some banks, customers can also enable/disable card usage, change spending limits, or freeze their cards independently through the bank's application, aside from contacting the bank.

The BOT and the Thai Bankers Association place great importance on the security of financial transactions and the protection of customers' personal data. Banks have security systems in place and continuously monitor for unusual transactions. Moving forward, the BOT and financial institutions will collaborate with relevant agencies to enhance measures and improve the detection and response to unusual transactions to prevent and mitigate the impact of such incidents.