Check your Windows port associations

One vulnerable aspect of "Windows out of the box" is the UDP and TCP ports it uses to support file and print sharing, directory services and name resolution. Using these ports on any local area network for these purposes is tolerable. But for any link to the Internet, they definitely are not. One of my favorite security tools makes a compelling case for why you should never utilize either one. (See the screen text capture below, picked up verbatim from my Windows 2000 Professional laptop on my home network).

The tool in the illustration here is FPort. It's from a company named Foundstone. It's a company that includes as principals two of the folks behind the wildly successful (and entirely useful) Hacking Exposed books—namely George Kurtz and Stuart McClure. It also includes long-time PC Magazine programming editor, book author, and Windows guru Chris Prosise.

FPort lists all open TCP and UDP ports it discovers, along with the associated process ID (Pid) and process name (Process). The tool is free, easy to download, and

To continue reading for free, register below or login

Requires Membership to View

To gain access to this and all member only content, please provide the following information (all fields required):

First Name:
Last Name:
Country: Select... Afghanistan Aland Islands Albania Algeria American Samoa Andorra Angola Anguilla Antarctica Antigua and Barbuda Argentina Armenia Aruba Australia Austria Azerbaijan Bahamas Bahrain Bangladesh Barbados Belarus Belgium Belize Benin Bermuda Bhutan Bolivia Bosnia and Herzegovina Botswana Bouvet Island Brazil British Indian Ocean Territory British Virgin Islands Brunei Bulgaria Burkina Faso Burundi Cambodia Cameroon Canada Cape Verde Cayman Islands Central African Republic Chad Chile China Christmas Island Cocos (Keeling) Islands Colombia Comoros Congo Congo, Democratic Republic of Cook Islands Costa Rica Cote D'Ivoire Croatia Cuba Cyprus Czech Republic Denmark Djibouti Dominica Dominican Republic Ecuador Egypt El Salvador Equatorial Guinea Eritrea Estonia Ethiopia Falkland Islands Faroe Islands Fiji Finland France French Guiana French Polynesia French Southern Territories Gabon Gambia, The Georgia Germany Ghana Gibraltar Greece Greenland Grenada Guadeloupe Guam Guatemala Guernsey Guinea Guinea-Bissau Guyana Haiti Heard and McDonald Islands Honduras Hong Kong Hungary Iceland India Indonesia Iran Iraq Ireland Israel Italy Jamaica Japan Jersey Jordan Kazakhstan Kenya Kiribati Korea, North Korea, South Kuwait Kyrgyzstan Laos Latvia Lebanon Lesotho Liberia Libya Liechtenstein Lithuania Luxembourg Macau Macedonia Madagascar Malawi Malaysia Maldives Mali Malta Man, Isle of Marshall Islands Martinique Mauritania Mauritius Mayotte Mexico Micronesia Moldova Monaco Mongolia Montserrat Morocco Mozambique Myanmar Namibia Nauru Nepal Netherlands Netherlands Antilles New Caledonia New Zealand Nicaragua Niger Nigeria Niue Norfolk Island Northern Mariana Islands Norway Oman Pakistan Palau Palestine Panama Panama Canal Zone Papua New Guinea Paraguay Peru Philippines Pitcairn Poland Portugal Puerto Rico Qatar Reunion Romania Russia Rwanda Saint Helena Saint Kitts and Nevis Saint Lucia Saint Pierre and Miquelon Saint Vincent and the Grenadines Samoa San Marino Sao Tome and Principe Saudi Arabia Senegal Serbia and Montenegro Seychelles Sierra Leone Singapore Slovakia Slovenia Solomon Islands Somalia South Africa South Georgia and South Sandwich Islands Spain Sri Lanka Sudan Suriname Svalbard Swaziland Sweden Switzerland Syria Taiwan Tajikistan Tanzania Thailand Timor-Leste Togo Tokelau Tonga Trinidad and Tobago Tunisia Turkey Turkmenistan Turks and Caicos Islands Tuvalu U.S. Minor Outlying Islands Uganda Ukraine United Arab Emirates United Kingdom United States Uruguay Uzbekistan Vanuatu Vatican City Venezuela Vietnam Virgin Islands Wallis and Futuna Islands Western Sahara Yemen Zambia Zimbabwe
Email Address:

I would like to receive a FREE subscription to Information Security magazine online.
YesNo

Do you manage, evaluate, recommend, implement, support or purchase security products, software or services?
YesNo

Please estimate the yearly security budget for your entire organization including all security products and services.
Please select... Over $10 Million $5 Million-$10 Million $1 Million-$4.9 Million $500,000-$999,999 $100,000-$499,999 $50,000-$99,999 $25,000-$49,999 $10,000-$24,999 Less than $10,000 None

What is your role in purchasing IT related products and services? (Check all that apply)
Technical decision maker
Financial decision maker
Recommend/Specify
Evaluate products
Implement Products/Services
Determine Needs
Create Security Strategy
None

By joining SearchSecurity.com you agree to receive email updates from the TechTarget network of sites, including updates on new content, magazine or event notifications, new site launches and market research surveys. Please verify all information and selections above. You may unsubscribe at any time from one or more of the services you have selected by editing your profile or unsubscribing via email.

TechTarget cares about your privacy. Read our Privacy Policy

Why is this tool valuable? Because it shows all TCP and UDP ports open on the machine where it runs. This defines the set of ports you should inspect and block at the interface (or firewall) that connects your machine or network to the Internet. For the screen display shown above, you'd want to close all ports shown below 1,024 and be pretty picky about which applications (namely, the Task Scheduler, MSTask.exe; various elements of Norton Internet Security, Internet Explorer and so forth) are allowed Internet access.

By combining judicious external scans of your system(s) or network (readily available at Gibson Research or Symantec (to name just two of many such tools) with the "inside view" that FPort provides, you can easily learn what ports to check and block, as needed.

Thomas Alexander Lancaster IV is a consultant and author with over 10 years experience in the networking industry, focused on Internet infrastructure.