FruitFly, a piece of Mac malware that infected thousands of machines over the course of more than 13 years, was being distributed via poorly protected external services.
First detailed in early 2017, FruitFly (also known as Quimitchin) targeted individuals, companies, schools, a police department, and the U.S. government, including a computer owned by a subsidiary of the Department of Energy.
In January this year, the U.S. Department of Justice indicted Phillip R. Durachinsky, an Ohio resident, for using the malware for more than 13 years for nefarious purposes. The man would abuse FruitFly to steal personal data of unknowing victims and spy on them, and even to produce child pornography.
Durachinsky allegedly leveraged the malware to control the infected machines “by accessing stored data, uploading files, taking and downloading screenshots, logging a user’s keystrokes, and turning on the camera and microphone to surreptitiously record images and audio,” the DoJ said in January.
While the threat’s capabilities were clear to the researchers who analyzed it, the only thing they couldn’t explain was the infection vector.
A newly discovered “flash alert” (PDF) that the Federal Bureau of Investigation (FBI) sent in March last year, however, solves the mystery: Durachinsky targeted poorly protected external services to install the malware onto his victims’ machines.
“The attack vector included the scanning and identification of externally facing Mac services to include the Apple Filing Protocol (AFP, port 548), RDP, VNC, SSH (port 22), and Back to My Mac (BTMM), which would be targeted with weak passwords or passwords derived from 3rd party data breaches,” the alert reads.
Discovered by Patrick Wardle, co-founder and chief research officer of enterprise macOS security company Digita Security, the document reveals that, in addition to using the malware to spy on victims, Durachinsky was leveraging the infection to target additional systems.
Basically, he scanned the Internet for Macs with exposed ports that he could exploit and then attempted to connect to these systems using weak, known credentials. Once a system was compromised, he then attempted to persistently install the malware.
The targeting of poorly protected remote access protocols for malware installation isn’t a new technique. In fact, there are millions of endpoints exposing ports associated with the Remote Desktop Protocol (RDP) and this type of attack even surpassed spam in popularity among ransomware operators.
Related: Mac Malware Creator Indicted in U.S.