Researchers observed a new crypto-mining malware campaign that uses a process hollowing method and a dropper component to deploy Monero miner on windows installations.
Process hollowing is a method to hide the presence of the process by replacing it with a secondary process. and the dropper file acts as a container. Malicious activity can be triggered only by supplying correct arguments.
The dropper file is not malicious, it needs a specific set command argument to trigger the malicious activity, this allows attackers to evade detection.
Monero Miner Infection
Trend Micro observed a sharp increase in malicious activity starting from November, the campaign primarily targets Kuwait, Thailand, India, Bangladesh, the United Arab Emirates, Brazil, and Pakistan.
“The dropper is a 64-bit binary packed with malicious code, upon execution it checks for certain arguments passed to it and verify it upon unpacking.”
The malware infection goes through two stages, the first stage performs an arithmetic operation on alphanumeric strings, researchers examined the alphanumeric string and it includes information including cryptocurrency wallet address which is the required argument to trigger the malicious activity.
Once the dropper executed with correct arguments it drops and executes the wakecobs[.]exe process in the suspended state and the dropper replaces the process memory malicious code which allows XMRig miner to run on the background.
The XMRig abuses the computer’s resources to mine Monero blocks, it causes the computer to overheat and to perform poorly.
Monero is the primary choice of crypto-mining malware operations because of it’s attractive features like untraceable transactions and proof-of-work algorithm CryptoNight which is suitable for normal PC CPUs without requiring any special devices.
Indicators of Compromise (IoCs)