News

Outlook Express Feature Could Let Viruses Slip Past Virus Scanners, Firewalls

A security firm discovered that users who enable a rarely used feature in Microsoft's Outlook Express client could allow viruses, trojans and worms to slip past the usual array of perimeter security defenses, including gateway virus scanners, SMTP-checking firewalls and content filters.

Outlook Express has a feature that allows users with slow connections to download large messages in pieces so they can begin reading the message without waiting for the entire file to download. Users can enable the feature with a few clicks in the Outlook Express Tools menu.

This feature "allows anyone to bypass most of the security restrictions imposed on e-mail messages, due to the fact that messages are spliced into smaller segments that will not be detected by virus scanners or other content testing mechanisms," according to a bulletin on the Web site of Beyond Security Ltd., the firm that reported the vulnerability.

The feature, called "message fragmentation and re-assembly," allows attackers to separate virus signatures so they are only reassembled at the client.

Several third-party vendors acknowledged that their products are vulnerable to the Outlook Express problem and have created patches, including Trend Micro and GFI.

About the Author

Scott Bekker is editor in chief of Redmond Channel Partner magazine.

Featured

  • Windows 10 Preview Adds Ability To Display Linux Distro Files

    Microsoft on Wednesday announced Windows 10 preview build 19603, which adds easier access to installed Linux distro files using Windows File Explorer.

  • Microsoft 365 Business To Get Azure Active Directory Premium P1 Perks

    Subscribers to Microsoft 365 Business (which is being renamed this month to "Microsoft 365 Business Premium") will be getting Azure Active Directory Premium P1 licensing at no additional cost.

  • How To Use .CSV Files with PowerShell, Part 1

    When it comes to bulk administration, few things are handier than .CSV files. In this two-part series, Brien demos his top techniques for working with .CSV files in PowerShell. First up: How to create a .CSV file.

  • SameSite Cookie Changes Rolled Back Until Summer

    The Chromium Project announced on Friday that it's delaying enforcement of SameSite cookie changes, and is temporarily rolling back those changes, because of the COVID-19 turmoil.

comments powered by Disqus

Office 365 Watch

Sign up for our newsletter.

Terms and Privacy Policy consent

I agree to this site's Privacy Policy.