The National Intelligence Service(NIS) has found that an unidentified group of hackers stole personal information from some 13-thousand accounts of users of government and state agencies' online service and illegally distributed the data via dark web or Telegram.

The top intel agency said on Monday that the hackers were found to have stolen log-in info, including IDs and passwords, that were saved in web browsers after spreading the Infostealer malware via blogs.

The agency said it notified the affected agencies and had them swiftly take measures to prevent any further damage. 

The NIS urged those who use functions on auto saving IDs and passwords to exercise extra caution, warning that they can suffer greater damage from ransomware attacks should their stolen information end up in the hands of other hackers via illegal distribution.

The agency called on the public to refrain from using the auto-save function and from installing suspicious software.