Hackers who succeeded in penetrating the websites of several Polish banks last week appear to be behind a wave of malware attacks that have targeted banks in 31 countries since the end of last year. The attackers used compromised websites or “watering holes” to infect pre-selected targets with previously unknown malware, according to Symantec.
The attacks came to light when a bank in Poland discovered previously unknown malware running on a number of its computers. The bank then shared indicators of compromise (IOCs) with other institutions who subsequently confirmed that they too had been compromised. The source of the attack appears to have been the website of the Polish financial regulator, which was compromised to redirect visitors to an exploit kit which attempted to install malware on selected targets.
Symantec said that since October last year, it has blocked attempts to infect customers in Poland, Mexico, and Uruguay by the same exploit kit that infected the Polish banks. The attackers appear to be using compromised websites to redirect visitors to a customized exploit kit, which is preconfigured to only infect visitors from approximately 150 different IP addresses, says the security group. These IP addresses belong to 104 different organizations, mostly banks, located in 31 different countries.