- Feb 4, 2016
An ongoing Zloader campaign uses a new infection chain to disable Microsoft Defender Antivirus (formerly Windows Defender) on victims' computers to evade detection.
According to Microsoft's stats, Microsoft Defender Antivirus is the anti-malware solution pre-installed on more than 1 billion systems running Windows 10.
The attackers have also changed the malware delivery vector from spam or phishing emails to TeamViewer Google ads published through Google Adwords, redirecting the targets to fake download sites.
From there, they are tricked into downloading signed and malicious MSI installers designed to install Zloader malware payloads on their computers.
"The attack chain analyzed in this research shows how the complexity of the attack has grown in order to reach a higher level of stealthiness," said SentinelLabs security researchers Antonio Pirozzi and Antonio Cocomazzi in a report published today.
"The first stage dropper has been changed from the classic malicious document to a stealthy, signed MSI payload. It uses backdoored binaries and a series of LOLBAS to impair defenses and proxy the execution of their payloads.