Kronos Malware Returns With New Attack Campaigns, Updates

The Kronos banking trojan has returned with several new attack campaigns as well as a few updates.

In April 2018, researchers at Proofpoint detected a new variant of the malware. It’s the first time Kronos surfaced after largely disappearing from the threat landscape. Given that absence, the trojan’s operators didn’t waste any time in getting up to no good.

Proofpoint observed the first malware campaign at the end of June. As part of that operation, bad actors posed as German financial companies and sent attack emails to German users with subject lines informing them of updates made to their terms and conditions. Other versions of the campaign notified them of a “reminder.” All instances of the campaign contained Word documents that used malicious macros to download Kronos.

The second and third campaigns both occurred in mid-July. For the former, attackers targeted Japan with a malvertising chain that sent users to websites containing malicious JavaScript. Those sites redirected users to the RIG exploit kit that distributed Smoke Loader, just one type of malware served by the compromised website of a Ukraine-based accounting software developer back in August 2017. Smoke Loader then downloaded Kronos.

For the third campaign, nefarious individuals targeted Polish users with emails notifying recipients of fake invoices. Attached were Word documents that activated Kronos through the help of malicious macros.

In the days that followed, the researchers also spotted a “work in progress” campaign with Kronos downloaded from a “GET IT NOW” button on a website claiming to be a music streaming service.

Most of these campaigns shed light on an important change made to the banking trojan: the threat now uses .onion C&C URLs and Tor. This technique anonymizes Kronos’s communications and thereby helps it evade detection.

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