South Korean regulators have imposed sanctions on SK Telecom , the country's largest mobile phone provider, after revealing a large-scale personal data breach that affected nearly 27 million users .
The cyberattack, which was revealed in April and attributed to malware, led to the leakage of millions of customers' information. In response, the Science Ministry announced on Friday a fine of up to 30 million won (about $22,000) and imposed measures of security.
Specifically, SK Telecom should:
- Implement a security audit every quarter
- To boost investment and personnel in the cybersecurity sector
- Ensure that the company CEO will personally oversee data management
See also: Kelly Benefits: Data breach affects 550,000 people
“This… was a wake-up call for information protection not only in the domestic telecommunications industry but also in the overall network infrastructure,” Science Minister Yoo Sang-heeafter the investigation was completed.
SK Group chairman Chey Tae-won publicly apologized for the incident, while the company pledged to take full responsibility for any damage users suffer due to the data breach.
As part of the compensatory actions, SK Telecom announced that it will offer free cards USIM through more than 2,600 retail stores nationwide.
By the end of June, about 9.4 million users had already replaced their USIM cards, according to official company data.
See also: Qantas: Cyberattack led to data breach
Telecommunications Companies: Ways to Protect Yourself
Traditional protection methods are no longer enough when it comes to threats like the Salt Typhoon group. Telecom companies must move to deeper strategies:
1. Instant software updates & patches
- It is not acceptable in 2025 for critical vulnerabilities to remain active for months.
- Speed is required in updating firmware on routers, firewalls, VPN gateways.
2. Zero Trust Architecture
- Zero trust in internal and external devices – no access without strict verification.
3. Network segmentation & accessibility minimization logic
- Separation of critical systems to prevent lateral movementofattackers.
See also: Johnson Controls: Notifies individuals about 2023 data breach
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4. Empowering edge devices
- Hardening of routers, firewalls, load balancers, frequent checking of settings and firmware.
- Using anomaly detection and AI-based behavioral analytics.
5. Risk assessment of third parties (MSPs, cloud providers)
- Complete supply chain control (supply chain risk management).
- Active security contracts and mandatory measures for suppliers.
6. Threat hunting & red teaming
- Passive defenses are not enough – aggressive detection of suspicious activity by special teams is required.
Source: Reuters
