INSPECTING ARCHIVED INTELLIGENCE (OUTDATED VERSION).

High5's 163,743 users' info leaked due to hacking

| 2026-11-02 01:57 MEDIUM LOW DATA BREACH
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Executive Summary
AI-generated
High5, a popular reservation and discount service in South Korea, has revealed that the personal information of 163,743 users was leaked due to a hacking incident in September. To compensate for the damage, the company has announced that it will provide a 20,000 won discount coupon to affected customers. According to a notice posted on High5's app on September 10, the incident occurred around 2 pm on September 3, and the company became aware of the leak on the evening of September 7.
Technical Mitigations AI-generated
• Audit (ATT&CK mitigation for Phishing): Perform audits or scans of systems, permissions, insecure software, insecure configurations, etc. • User Training (ATT&CK mitigation for Impersonation): Train users to be aware of impersonation tricks and how to counter them, for example confirming incoming requests through an independent platform like a phone call or in- • Reset credentials and API keys that may have been exposed, and review access logs for the affected accounts or integrations.
Intelligence Metadata
Actors / Malware / CVEs / Campaigns
Target & Sectors
KR
financefinance
Incident Timeline
‎2026/11/02
Threat actors from Thailand exploited a security vulnerability in High5's API to access the personal information of 163,743 users.
victims 163,743 users
High5, a popular reservation and discount service in South Korea, has revealed that the personal information of 163,743 users was leaked due to a hacking incident in September.
organisation API
The attackers exploited a security vulnerability in the app's interface (API) to access the personal information of users who were using lower versions of the app.
organisation the partner bank
The leaked information includes the user's nickname, phone number, reservation records, including the partner bank name, usage amount, and reservation status, as well as the payment-related data, including the order date, transaction ID, and cancellation key.
organisation the Korea Internet & Security Agency
The company reported the incident to the Korea Internet & Security Agency (KISA) and notified the affected customers individually.
organisation KISA
The company reported the incident to the Korea Internet & Security Agency (KISA) and notified the affected customers individually.
Tactical Metrics
Metrics
victims
163,743
Users
High5, a popular reservation and discount service in South Korea, has revealed that the personal information of 163,743 users was leaked due to a hacking incident in September.
Intelligence Sources
Dailysecu 2026-11-02