ESET researchers have discovered that the criminals behind the Stantinko botnet are distributing a cryptomining module to the computers they control
The operators of the Stantinko botnet have expanded their toolset with a new means of profiting from the computers under their control. The roughly half-million-strong botnet – known to have been active since at least 2012 and mainly targeting users in Russia, Ukraine, Belarus and Kazakhstan – now distributes a cryptomining module. Mining Monero, a cryptocurrency whose exchange rate oscillates in 2019 between US$50 and US$110, has been the botnet’s monetizing functionality since at least August 2018. Before that, the botnet performed click fraud, ad injection, social network fraud and password stealing attacks.
In this article, we describe Stantinko’s cryptomining module and provide an analysis of its functionality.
This module’s most notable feature is the way it is obfuscated to thwart analysis and avoid detection. Due to the use of source level obfuscations with a grain of randomness and the fact that Stantinko’s operators compile this module for each new victim, each sample of the module is unique.
We will describe the module’s obfuscation techniques and offer, in a separate article for fellow malware analysts, a possible approach to deal with some of them.
Since Stantinko is constantly developing new and improving its existing custom obfuscators and modules, which are heavily obfuscated, it would be backbreaking to track each minor improvement and change that it introduces. Therefore, we decided to mention and describe only what we believe are significant adjustments in comparison with earlier samples relative to the state in which the module is to be described. After all, we intend just to describe the module as it currently ..