Threat behavior
Worm:Win32/Fakerecy.A is a worm that spreads via logical drives. To avoid detection, it places its files in a fake Recycle Bin folder that it creates.
Installation
Upon first execution, Worm:Win32/Fakerecy.A creates the following folder and files in the system drive:
Note that a legitimate Windows file also named ctfmon.exe exists in the Windows system folder.
The file autorun.inf contains commands to run ctfmon.exe. As a result, if the AutoPlay feature is enabled, Fakerecy.A is run when a user accesses the system drive using Windows Explorer.
A copy of this worm, also named ctfmon.exe, is placed in the Windows startup folder, ensuring that it automatically runs every time Windows starts up.
Spreads Via...
Logical Drives
Upon second execution, Worm:Win32/Fakerecy.A spreads to other local and network drives by creating the following folder and files:
These files are virtually identical in function to the ones initially dropped in the system drive.
Analysis by Shali Hsieh
Prevention