SK Telecom — Cyber Attacks, Breaches & Threat Activity

Threat entity extracted from intelligence sources

Frequency
32
occurrences
First Seen
November 3, 2025
Last Seen
July 30, 2026

SK Telecom (SKT) is South Korea’s leading wireless carrier and a major telecom operator.

Overview

SK Telecom (SKT) is South Korea’s leading wireless carrier and a major telecom operator. It has recently faced heightened cybersecurity scrutiny, including a large data breach penalty and legal challenges, plus security shortcomings in its femtocell infrastructure and regulatory pushes to tighten SIM security—highlighting the ongoing privacy and threat landscape affecting mobile networks.

Related Threat Clusters

  • Korean Diplomatic Academy Hacked for Nearly 10 Months, Data Potentially Compromised

    The Korea National Diplomatic Academy's online training platform was hacked for nearly 10 months, from April 2025 to February 2026. Attackers exploited a zero-day vulnerability in the server software, allowing them to…

    35 articles · Updated July 20, 2026
  • KT Corp Fined ₩53.97 Billion for Femtocell Breach and Evidence Tampering

    KT Corp was fined ₩53.97 billion (approximately $37.6 million) by South Korea's privacy regulator for failing to secure its femtocell system, allowing unauthorized access to its mobile network. The breach began in…

    7 articles · Updated July 30, 2026
  • SK Telecom Malware Breach Affects 27 Million Customers Over Three Years

    SK Telecom, South Korea's largest mobile network operator, reported a malware breach that lasted nearly three years, impacting approximately 26.95 million customers. The breach, detected on April 19, 2025, involved…

    2 articles · Updated July 13, 2026
  • Coupang Data Breach Affects 33.7 Million Customers in South Korea

    Coupang, South Korea's largest online retailer, confirmed a data breach affecting 33.7 million customer accounts. The breach has prompted an emergency meeting among senior government officials as it potentially impacts…

    2 articles · Updated December 1, 2025
  • South Korea Implements Universal Basic Mobile Data Access Amid Security Concerns

    On April 11, 2026, South Korea launched a universal basic mobile data access scheme to ensure all citizens have access to online services. This initiative was prompted by recent security lapses among the country's…

    2 articles · Updated April 11, 2026
  • Coupang Data Breach Affects 33.7 Million Users

    Coupang experienced a significant data breach, exposing personal information of approximately 33.7 million users. The leaked data includes names and addresses, prompting the company to warn users about potential scams…

    94 articles · Updated November 29, 2025
  • Singapore Telcos Targeted by UNC3886 Cyberattack

    In July 2025, an advanced persistent threat actor known as UNC3886 targeted Singapore's four telecommunications companies, compromising critical infrastructure. The attack was detected by the Infocomm Media Development…

    78 articles · Updated February 9, 2026
  • SK Telecom Challenges $91 Million Penalty for Data Breach

    SK Telecom has filed a legal challenge against a $91 million penalty imposed by the Personal Information Protection Commission. This penalty was a result of a cyberattack in April 2025 that compromised the personal data…

    2 articles · Updated January 21, 2026
  • SK Telecom Appeals $91M Fine Over USIM Data Breach

    SK Telecom has initiated legal proceedings to contest a $91 million fine imposed by the Personal Information Protection Commission due to a data breach involving USIM cards in April 2025. The company argues that it has…

    1 article · Updated January 20, 2026
  • SK Telecom Ordered to Compensate Users Over Data Breach

    The Korea Consumer Agency has mandated SK Telecom to pay 100,000 won ($67) to each of the 23 million users affected by a significant data breach earlier this year. This decision follows a mediation request from 58…

    6 articles · Updated December 21, 2025

Recent Intelligence Reports

  • KT had deployed thousands of femtocells across its network using shared certificates stored in plaintext on each device, without root password protection and with SSH enabled for remote access — www.theregister.com · July 30, 2026
  • Korea Fines KT for Rogue Femtocell Breach, Refers Both Carriers to Police — Techtimes · July 30, 2026
  • KT hit with W54b penalty over data breach — M.Koreaherald · July 30, 2026
  • South Korea's Diplomatic Roster Exposed by Zero-Day for Nearly Ten Months — Techtimes · July 20, 2026
  • Telecoms step up cybersecurity spending after breaches — Koreatimes.Co.Kr · July 13, 2026
  • Sk Telecom Says Malware Breach Lasted 3 Years Impacted 27 Million Numbers — www.bleepingcomputer.com · July 11, 2026
  • South Korea introduces universal basic mobile data access — News.Ycombinator · April 11, 2026
  • South Korea introduces universal basic mobile data access — Theregister · April 10, 2026

CVSS v3.1 Breakdown