Users of Microsoft Internet Explorer could be tricked into downloading and running a malicious program which is disguised as an innocent file, a Finnish security company has warned.
Malicious activity via the back door
The filename as it appears in the IE file download dialog box can be faked by using certain URLs and HTTP headers on a web page, making the user think he is opening a media file when in fact he is installing a "backdoor" program on his PC, according to Oy Online Solutions.
A backdoor program can be used by hackers to enter a user's PC.
IE won't show the warnings it typically displays when a program file is downloaded or opened, because the EXE file extension may have been hidden or replaced with another such as TXT or HTM.
The file is run without any warnings because IE, just as the user, thinks it is a harmless file.
Microsoft has issued a patch for IE 5.0, 5.5 and 6.0, which should be available next week.