Windows 7 putting users at risk

happygeek 0 361 Views

With the Windows 7 release code out there and available for download right now, and free to use until 2010 for good measure, the last thing Microsoft will want to hear is bad news about potential security risks for users of the new flagship OS. But that's exactly what researchers over at security outfit F-Secure is delivering.

The Helsinki-based F-Secure reckons that a well known and long-lambasted problem that has existed in Windows NT, Windows 2000, Windows XP and Vista has not been fixed. That problem is Explorer hiding extensions for known file types. F-Secure claims that virus writers have long used this feature in order to trick people into thinking executables are simple document files and the like. Double naming virus.exe to virus.txt.exe would result in Windows hiding the .exe part and leaving the unsuspecting user seeing what looks like a .txt file instead of the actual executable, aided and abetted by the bad guys changing the icon inside the executable to seal the deal.

F-Secure tried the age old trick using Windows 7 and, oh dear, you can probably guess the rest.

"Bottom line: We still fail to see why Windows insists on hiding the last extension in the filename. It's just misleading" says F-Secure.

Microsoft has with Windows 7 security in the past, but the chances of it doing the same with this potential risk are pretty slim I would imagine. After all, it has had many years to correct the error and decided not to, so why change now?

Dani AI

Generated

rightly flags a real UI weakness that attackers can exploit. Showing the file extension by default is a simple, effective first step that removes a common trick social engineers use — it’s not a cure-all, but it closes one of the easiest traps.

To turn on full extensions in Windows Explorer (per-user):

  • Open any folder, click Organize → Folder and search options.
  • Choose the View tab.
  • Uncheck "Hide extensions for known file types", click Apply → OK.
    After this you’ll see complete filenames (e.g., report.docx instead of just report), which makes spoofed names far easier to spot.

For power users and administrators: the setting is stored in the registry. To show extensions, set:

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
Value: HideFileExt (DWORD) = 0

Deploy this via Group Policy Preferences or a logon script to force the behavior across users if you manage multiple machines.

Other practical mitigations to pair with the above:

  • Treat icons and file names with caution; verify a file’s Type/Properties before opening.
  • Run up-to-date anti-malware and scan suspicious files (or upload to a scanning service) before executing.
  • Limit user rights — don’t run daily as an administrator; use AppLocker/Software Restriction policies where possible.
  • Educate users about Unicode tricks like right-to-left override (RTLO) and other filename obfuscation techniques.

Turning on extensions increases visibility and reduces accidental execution of malicious binaries, but maintain layered defenses (patching, AV, least privilege, user training).

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