How the RLO unicode character is used by malware:
[...] This virus's file name is crafted in a way that PC users take it for a benign file from its appearance (mainly the file extension) and open it.
This virus falsifies its file name extension by using a Unicode control character, so that such a malignant file looks like benign one. Unicode refers to a standard for consistent encoding, representation and handling of text expressed in languages in the world. Control characters are characters that are defined in character code but are not displayed on the screen, and used to control devices such as printers and communication devices.
The control character used by this virus is RLO (Right-to-Left Override). This control character is designed to reverse a character sequence from "left-to-right" to "right-to-left". This function is used by the people who want to read a language like Arabic that is read from right to left in reverse sequence (i.e., left-to-right), as they would in the case of Japanese and English.
More info on bidirectional text at its Wikipedia article: Bidirectional text.
You can try this RLO character test webpage to see how the RLO character works. The RLO character is also already entered in the 'Input Test' field in that webpage. Try typing there and notice that the characters you're typing are coming out in their reverse orders (right-to-left, instead of left-to-right).
The RLO character can be specifically positioned in the filename to spoof or masquerade a file as having a filename or file extension that is different than what it actually has. (Will still be hidden even if 'Hide extensions for known filetypes' is unchecked.)
As a security measure, what are ways to prevent files with the RLO Unicode character in their filenames from being written, read, or run?
My OS is Windows 7, but feel free to suggest solutions for other OSes too.
They adviced to use the Local Security Policy settings manager to block files with the RLO character in its name from being run.
Can you please tell us why this is not a solution?