Cybercriminals are building country-specific botnets to target Brits that bank online with specific malware, says Trusteer.
The security firm has identified two pieces of malware – the previously undetected Silon.var2 and the longer-established Agent.DBJP – as the two bank Trojans being distributed by Zeus-based botnets using UK-infected PCs.
Silon.var2 now affects one in every 500 UK-based PCs connected to the Trusteer Flashlight system, 40 times the detection level for the US, with Agent.DBJP affecting one in every 5,000 UK-based PCs, again far higher than for the US.
It's not clear whether these detection rates are partly a quirk of the Trusteer customer base, but it is clear that country-specific malware is now a defined strategy for the banking trojan botnets, with the UK high on the hit-list.
Although country-specific malware can apply to any country, the motivation for attacking banks and their customers in this way is to make detection harder. Global Trojan campaigns are simply easier to spot.
"Regional malware is not unique to the UK," said Trusteer CEO, Mickey Boodaei.
"We've recently started analysing financial malware in South Africa and identified targeted regional attacks as well, which are rarely seen outside that region. Other regions such as Germany for example also suffer from regional malware. The infamous Yaludle malware has been highly focused on the German market," he said.
Trusteer's commercial motivation is to push its 'Rapport' browser plug-in to UK banks through which an encrypted link is set up between the banking sites and the customer. The technology is already being used in the UK by HSBC, and was itself recently and unsuccessfully targeted by malware writers trying to overcome its protection settings.