The data in question was leaked in the early hours of Tuesday, Polish state news agency PAP reported.
“A huge set of login and password data belonging to Polish citizens” surfaced online, according to officials.
Digitisation Minister Janusz Cieszyński said in a tweet on Wednesday: “We have launched a simple tool to enable citizens to check if their data were part of the leak. I invite everyone to use it at https://bezpiecznedane.gov.pl.”
The search facility can be accessed after logging onto a citizen’s profile for using public services online, the so-called "trusted profile," officials said.
The personal-data breach was first reported by the ZTS (zaufanatrzeciastrona.pl) website, according to the PAP news agency.
Several million Poland-based logins and passwords were leaked online, the website said.
It is impossible to estimate the number of people affected by the breach, but they are unlikely to be in the millions, as the virus could have obtained many passwords from a single computer, according to ZTS.
‘Malware attack' targeting 'browser-saved logins and passwords’
The website said the leak had been caused by “malware designed to locate browser-saved logins and passwords and pass them on to the creators of the virus.”
A file named ”pl.txt.” with data about online accounts used by Polish citizens, including logins, passwords and website addresses, "possibly as recent as from 2023," was published on a Polish-language forum on the TOR network that enables anonymous communication, the PAP news agency reported, citing ZTS.
The file was published by an account set up two months earlier and with no previous posting history, according to PAP.
The websites that feature most prominently in the database include facebook.com, allegro.pl, .gov.pl, poczta.onet.pl, poczta.wp.pl, online.mbank.pl, .ingbank.pl, x-kom.pl and morele.net, ZTS said.
Source: PAP, ZTS