Custom dropper hide and seek

Most users assume they are safe when surfing the web on a daily basis. But information-stealing malware can operate in the background of infected systems, looking to steal users’ passwords, track their habits online and hijack personal information.

Cisco Talos has monitored adversaries which are behind a wave of ongoing campaigns dropping well-known information-stealer like Agent Tesla, Loki-bot and others since at least January 2019. The adversaries using custom droppers, which inject the final malware into common processes on the victim machine. Once infected, the malware can steal information from many popular pieces of software, including the Google Chrome, Safari and Firefox web browsers.

The injection techniques we’re seeing in the wild are well-known and have been used for many years, but with the adversaries customizing them, traditional anti-virus systems are having a hard time detecting the embedded malware. In this post, we’ll walk through one of these campaigns in detail and how the different stages of the dropper hide the malware. Any internet user is a potential target of this malware, and if infected, has the potential to completely take away a user’s online privacy.