Invalidate LANMan

One of the easiest holes to exploit in Windows Security is the LANManager security. LANManager is an incredibly weak security system that was used eons ago, back in the Windows for Workgroups (Windows 3.1) days. And of course, in the interests of backwards compatibility, it has lived on and on through each subsequent version of Windows. If you're interested in security, getting rid of older versions of Windows should really be a priority. This tip contains two ways to prevent LANManager from coming back to haunt you, but they assume you don't have Windows NT or earlier systems in your environment.

First, use long passwords. The hash algorithm in LanManager only worked up to 14 characters, so passwords longer than 14 characters cannot be broken by the simple mechanisms routinely used to crack LanManager passwords.

Second, consider using Unicode in your password. It's fairly common for people to use punctuation marks and other non-standard characters from your keyboard in passwords to make them harder to guess, but Unicode passwords go an extra step, since LANManager doesn't do Unicode. However, they're a little harder to enter. Generally, you can hold the ALT key and type a 4-digit number from the keypad to enter Unicode characters. (Unicode characters are two-bytes and exist generally to support large alphabets.)

Thomas Alexander Lancaster IV is a consultant and author with over ten years experience in the networking industry, focused on Internet infrastructure.

This was first published in March 2003

There are Comments. Add yours.

TIP: Want to include a code block in your comment? Use <pre> or <code> tags around the desired text. Ex: <code>insert code</code>

REGISTER or login:

Forgot Password?
By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy
Sort by: OldestNewest

Forgot Password?

No problem! Submit your e-mail address below. We'll send you an email containing your password.

Your password has been sent to:

Disclaimer: Our Tips Exchange is a forum for you to share technical advice and expertise with your peers and to learn from other enterprise IT professionals. TechTarget provides the infrastructure to facilitate this sharing of information. However, we cannot guarantee the accuracy or validity of the material submitted. You agree that your use of the Ask The Expert services and your reliance on any questions, answers, information or other materials received through this Web site is at your own risk.