Polish Banks Infected with Malware Hosted on Their Own Government’s Site

Several Polish banks said they suffered malware infections after their employees visited the site of the Polish Financial Supervision Authority (KNF), which had been previously infected to host a malicious JavaScript file.

Zaufana Trzecia Strona, a local Polish news site, first reported the attacks late Friday, last week. The news site said that during the past week, the security teams at several, yet unnamed, Polish banks detected downloads of suspicious files and encrypted traffic going to uncommon IPs situated in many foreign countries.

As employees at different banks started looking into their systems, they found malware installed on numerous workstations and even some servers.

KNF website hosted malicious JavaScript file

Subsequent investigations and a cooperation between different banks eventually discovered the source of the infection as being the official website of KNF, which, ironically, is the regulating body that keeps an eye out for the security of financial systems in Poland.

According to reports, KNF’s website had been compromised for well over a week, as an unidentified attacker had modified one of the site’s JavaScript files.

KNF website (via Zaufana Trzecia Strona)

Visitors accessing the KNF website would load the malicious JavaScript file as part of the website’s regular resources.

JavaScript file would lead to RAT infection

The JavaScript code worked by opening a hidden iframe and forcibly downloading a file on the victim’s computers. Users that discovered and executed this file would install a remote access Trojan (RAT) on their computers.