Who was sanctioned, and for what?

Attackers who had planted malware in systems of SK Telecom Co., Ltd. since August 2021 took 9.82 GB of data on around 23 million subscribers from the home subscriber server in April 2025, including USIM authentication keys and IMSI. The authority found a lack of network segregation and access controls, authentication data not securely encrypted, missing security updates, an inadequate set-up of the chief privacy officer function and late notification of those affected. It imposed a penalty surcharge of 134,791,000,000 KRW and an administrative fine of 9,600,000 KRW (134,800,600,000 KRW in total) and issued orders on security, governance and oversight of service providers and sales partners.

Authority / court

Personal Information Protection Commission (PIPC, 개인정보보호위원회)

Area of law

Data protection · Data breaches and data security

Legal basis

Personal Information Protection Act (개인정보 보호법) Art. 29, Art. 31(1) und (3), Art. 34(1); Sanktion nach Art. 64-2(1) Nr. 9

Action

Fine

Status of proceedings

unknown

Sector

Telecoms, IT and software

Repeat case

yes

Mitigating circumstances

Reduction of 30% because no benefit was derived and a further 50% for completed remediation, compensation of those affected and protective efforts; increase of 50% because the infringement lasted more than two years. Cooperation was not taken into account because documents were submitted late.

Liability of senior managers

There was no chief privacy officer (CPO) with overall responsibility; the company was ordered to define the CPO’s responsibility and role clearly and to rebuild its governance.

Published

28 Aug 2025

Original amount 134,800,600,000 KRW, converted at the ECB reference rate of 27 Aug 2025.

Checked against the official source on 4 Oct 2026 · Direct link