Week 51, 2025 security incident report
Hacking and data breach incidents newly reported 2025.12.15 ~ 12.21
Between 15 and 21 December 2025, four new incidents were recorded in South Korea, and as hacking incidents and security issues at the three major telecoms operators came to the fore, a leak of PlayTicket member data, an attempted hack of the law firm Barun, and TVING's detection of a credential stuffing attack and its notice urging password changes followed. South Korean cases spanned telecoms, performance ticketing, online video streaming and legal services, taking the form of personal data leaks, account attacks and intrusion attempts. Across all types in South Korea and abroad, personal data leaks were the most common at 33, followed by hacking/intrusion (18), ransomware (6) and DDoS (1). Overseas, of 54 new incidents, the SoundCloud case, in which the personal data of about 29.8 million accounts was leaked, was the largest by the scale of damage cited, and breaches at the University of Sydney and French and British government bodies, along with knock-on damage from the Foreign Office to the Home Office in the UK, were also notable.
By type
- Data breach30
- Hacking & intrusion17
- Ransomware6
- DDoS1
Key incidents in South Korea
Ticketing site Playticket member data leaked
Member data from performance ticketing site Playticket was leaked. The scale of the leak, the timing and the response have not been confirmed.
Read on 한겨레 ↗Hacking attempt targets Barun Law LLC
A hacking attempt targeted Barun Law LLC. Concerns over information security at law firms grew.
Read on 인베스트조선 ↗TVING detects credential stuffing attack, urges password changes
TVING detected a credential stuffing attack and took action. TVING announced that no data had been leaked and asked users to change their passwords.
Read on 보안뉴스 ↗Hacking incidents at South Korea's three telecoms operators spotlight security issues
Hacking incidents at South Korea's three mobile operators were highlighted as major security incidents of 2025. The timing, scale of damage and response for each individual incident have not been confirmed.
Read on 보안뉴스 ↗
Supply-chain breaches
Cyber-attack on Foreign Office raises data breach concerns
The Foreign Office was hit by a cyber-attack in October 2025. When the UK government confirmed the attack in December, it assessed the risk of impact on individuals as low. Ministers said they were fairly confident that personal data had not been put at risk.
Related reports: 3 · last report →
Key incidents in other countries
Personal data of about 29.8 million SoundCloud accounts leaked
29.8mImpact: Email addresses, names, locations and profile statistics of about 29.8 million accounts
SoundCloud confirmed the theft of member data in December 2025, and the scale of the leak was later confirmed at about 29.8 million accounts. The leaked information included email addresses, names, locations and profile statistics. The attackers demanded money, then released the data and launched email bombing attacks on users, employees and partners. SoundCloud urged users to be wary of phishing.
Related reports: 10 · last report →University of Sydney code repository breach exposes data of 27,000 people
27kImpact: Personal information of 27,000 people
An online code repository at the University of Sydney in Australia has been breached, exposing the personal information of 27,000 people, including staff, students and alumni. The repository held historical personal data files used for testing and other purposes during development. The university disclosed the data leak.
Related reports: 10 · last report →French Interior Ministry email servers hacked, confidential files accessed
The French Interior Ministry confirmed a cyber-attack on its email servers. An investigation was carried out into the email compromise and the access to confidential files, and a suspect was arrested. It is unclear whether claims that data on 16 million French people was exposed have been verified.
Related reports: 5 · last report →Cyber-attack on Foreign Office raises data breach concerns
The Foreign Office was hit by a cyber-attack in October 2025. When the UK government confirmed the attack in December, it assessed the risk of impact on individuals as low. Ministers said they were fairly confident that personal data had not been put at risk.
Related reports: 3 · last report →TriZetto's 2024 breach affected more than 3 million people
3mImpact: More than 3 million people
A 2024 breach at health insurance technology provider TriZetto affected patients. TriZetto said more than 3 million people were affected, and lawyers were looking into related lawsuits.
Related reports: 2 · last report →