Recent campaigns are pushing various malware via fake Flash updates that drop and install cryptocurrency miners and other threats such as information stealers, or ransomware.
In this campaign not only install the crypto mining malware but also update a victim’s Flash Player to the latest version.
This legitimate Flash update helps to trick victims who may not notice any unwanted behavior and crypto miners or other injected malware silently running in the background of the compromised victim’s computer.
- According to Palo Alto researchers, While searching for these particular fake Flash updates, we noticed Windows executables file names starting with AdobeFlashPlayer__ from non-Adobe, cloud-based web servers.
- These downloads always contained the string flashplayer_down.php?clickid= in the URL. We found 113 examples of malware meeting these criteria since March 2018 in AutoFocus. 77 of these malware samples are identified with a CoinMiner tag in AutoFocus.
Fake Flash Updates Infection Process
The initial stage of potential URL arriving at the victim’s machine and how URLs delivering fake Flash updates was unclear but tested sample generated Adobe Flash installer popup windows.
Once vicitms click the popup windows then it will process the Flash Player installation and the crypto miners will start and work in the background of the infected windows machine.
Later Potential victims will receive warnings about running such downloaded files on their Windows computer and also it warned that about an unknown publisher.
Once victims click “Yes” it downloads an actual Flash Player from Adobe and install the real Flash Player.
Later it asks users about the flash updates in order to install the downloaded updates right now or notify me later.
Researcher captures the download and installation traffic and it consisted mainly of the Flash update meanwhile his infected lab host soon generated traffic associated with XMRig cryptocurrency mining over TCP port 14444.
“Attackers using Monero wallet for this miner and once it begins the traffic Windows host generated an HTTP POST request to osdsoft[.]com. This domain is associated with updaters or installers pushing cryptocurrency miners and other unwanted software”, Researcher said.