Hackers entry delicate SIM card knowledge at South Korea’s largest telecoms firm

Cellular community operator SK Telecom, which serves roughly 34 million subscribers in South Korea, has confirmed that it suffered a cyber assault earlier this month that noticed malware infiltrate its inner techniques, and entry knowledge associated to prospects’ SIM playing cards.

The breach occurred at round 11pm native time, on the evening of Saturday 19 April 2025, in what’s believed to have been an assault deliberately timed to take advantage of a day and time when there could also be much less employees monitoring in place.

Responsibly, SK Telecom knowledgeable the Korean Web & Safety Company (KISA) the next day, and fulfilled its authorized obligation to inform the Private Data Safety Fee on Monday 21 April that there had been a possible knowledge breach.

Though no buyer names, beginning dates, or monetary particulars have been leaked, the knowledge figuring out SIM playing cards is taken into account extremely delicate – because it may allow a decided prison to hijack victims’ cellphone numbers in a “SIM Swap” assault.

SK Telecom says that its engineers detected and deleted the malware risk on its community, and took the compromised community servers offline as quickly because it realised {that a} knowledge breach might have occurred. Sadly, regardless of its finest efforts – hundreds of thousands of customers’ SIM particulars may have been put in danger, and will now be within the fingers of cybercriminals.

Though SK Telecom has not confirmed the whole variety of customers whose SIM particulars have been uncovered, it has acknowledged that hundreds of thousands of people may very well be in danger.

The excellent news is that SK Telecom says it has seen no proof that the delicate knowledge has been exploited by cybercriminals. The dangerous information is that it would not essentially know if it had been exploited or not.

Since its breach, SK Telecom has confronted some criticism for the best way it has communicated information of the cyber assault to its prospects. Though it up to date its web site and cell app with a safety advisory, some customers felt they need to even have proactively obtained an SMS alert informing them of the state of affairs.

Apologising for the breach and responding to complaints about its response to the incident, SK Telecom has apologised and begun to ship out SMS notifications to prospects. As well as, the corporate has stated it’s strengthening its safety within the hope of stopping related incidents in future, and pledged to have a clear inquiry into what occurred.

Hacks like this are a wake-up name for telecoms companies worldwide that they have to safe their techniques towards the specter of cybercriminals and state-sponsored hackers.

And all companies can be smart to study that hackers would possibly try and strike at anytime, day or evening, not simply throughout weekday enterprise hours.

If a hacker can exploit a window of alternative – akin to late within the night on a weekend – to sneak into your community undetected, they will not have any qualms about doing so.

Companies which can be dealing with crucial or delicate knowledge ought to guarantee their alerting techniques and incident response plans work by weekends and holidays simply as simply as another day of the week.