Ports to watch

The following provides a list of some port numbers that you should watch carefully. They are often associated with lax security and security breaches.

Identify the systems that are using these ports. If the application is a trusted, well-behaved application that should be loaded on that system, breathe a sigh of relief. If, however, the application is unnecessary or poorly behaved -- dump it!

• 7 echo
• 19 chargen
• 20 FTP data
• 21 FTP connection
• 22 ssh
• 23 telnet
• 25 SMTP
• 37 time
• 53 domain
• 110 POP3
• 111 SUNRPC
• 666 hack favorite
• 999 Winsatan
• 27444 Trinoo
• 27665 Trinoo
• 31335 Trinoo
• 31337 Back Orifice

Don't forget to check for any packets that are illogical in their structure. For example, packets sent to the NetBIOS-SSN port (139) with the Urgent flag set in the T...

Digg This!     StumbleUpon     Del.icio.us

VIEW ALL IN THIS CATEGORY

RELATED CONTENT Gathering statistics Measuring network hardware utilization A manager's guide to firewall logs Testing: One, two, three Getting DNS statistics and information Onsite network analysis Analyzing your network: Statistical monitoring vs. real-time performance Behavioral monitoring Making networks intelligent: The good, the bad and the symptomatic Network intelligence for dumb applications, Part 1 Net Intelligence column: A call for IPS, network behavior consolidation Testing Group Policy security What Ping doesn't tell you Rule your network's behavior Looking for trouble: ICMP and IP statistics to watch

RELATED RESOURCES 2020software.com, trial software downloads for accounting software, ERP software, CRM software and business software systems Search Bitpipe.com for the latest white papers and business webcasts Whatis.com, the online computer dictionary

CP header just doesn't make sense. This may cause an unpatched, older version of windows to belly-up and die -- this type of attack is called WinNuke or OOBNuke (out of bounds nuke).

For more security info, you can order Laura's "Security at the Packet Level" course or attend one of her seminars in person. Click here to find out more.

Also register to see Laura speak at Networking Decisions 2004.