The default operation performed to open a filetype is determining by referencing the filetype's CLSID. Due to a flaw in the interpretation of CLSIDs when appended to a filename, it is possible to specify a different default action for a given file than would normally be used. As a result, seemingly harmless files (.txt, .jpg etc) may be opened in a nonstandard, attacker specified manner. For example, a program ("evil.exe") could be renamed "evil.jpg.{CLSID_of_executables}" and when opened by the target user, this file will be executed instead of opened by their default .jpg viewer.
The default operation performed to open a filetype is determining by referencing the filetype's CLSID. Due to a flaw in the interpretation of CLSIDs when appended to a filename, it is possible to specify a different default action for a given file than would normally be used. As a result, seemingly harmless files (.txt, .jpg etc) may be opened in a nonstandard, attacker specified manner. For example, a program ("evil.exe") could be renamed "evil.jpg.{CLSID_of_executables}" and when opened by the target user, this file will be executed instead of opened by their default .jpg viewer.