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SKT hit with class-action seeking 4.6 billion won over SIM hack

Published: 16 May. 2025, 16:37

SK Group Chairman Chey Tae-won bows in apology during a press conference at SKT Tower in Jung District, central Seoul on May 7. [JOINT PRESS CORPS]

A total of 9,213 SK Telecom subscribers filed a class-action lawsuit on Friday in relation to the SK Telecom (SKT) SIM information hacking incident.

The lawsuit demands compensation of 500,000 won ($359) per person, totaling over 4.6 billion won, for damages suffered by SK Telecom customers.

“We are formally submitting the complaint for the first round of class-action damages against SK Telecom to the Seoul Central District Court to hold the company legally accountable and demand rightful compensation for the damages,” said attorney Ha Hee-bong of Lawpid Legal Service, representing the plaintiffs, during a press conference in front of the Seoul Central District Court on Friday.

“This lawsuit is not merely about a personal information breach, but about exposing SK Telecom’s blatant violation of its obligations as an information and communications service provider — both to protect personal information and to promptly report security incidents,” said Ha. “This was a foreseeable human-made disaster.”

On April 18, SKT suffered a large-scale data breach involving SIM information due to an attack believed to be from an external hacker. On May 7, SK Group Chairman Chey Tae-won publicly apologized and SK promised to establish an Information Security Innovation Committee to strengthen security across all group affiliates.

Plaintiffs in the class action are concerned not only about the leakage of their personal data but also the possibility of SIM cloning and further subsequent harm, according to Ha.

SK Telecom users wait in line to switch their SIM cards in front of a store in Jongno District, central Seoul, on April 29. [NEWS1]

Additionally, the hacking incident has caused subscribers inconveniences such as needing to replace their SIM cards and experiencing restricted access to certain financial services — disruptions to daily life that the plaintiffs argue amount to an infringement of their constitutionally guaranteed right to informational self-determination.

The plaintiffs are demanding that SK acknowledge its clear negligence in breaching both its duty to protect information and its reporting obligations and formally apologize.

They also called for the disclosure of the exact scope and content of the leaked data and a clear confirmation of whether SIM secret keys were leaked. SIM secret keys are critical security data and if exposed, could lead to identity theft and financial fraud.

“We urge government authorities, including the Ministry of Science and ICT, to thoroughly investigate the cause, hold SK Telecom strictly accountable for its legal violations, and immediately begin implementing meaningful institutional reforms — such as strengthening national oversight and management of core telecom servers — to prevent a recurrence,” said Ha.