IPS Signatures

TCP Source Port 0

 
Signature ID: 24199/0
Original Release:S477
Release:S477 (download)
Original Release Date:2010 March 12
Latest Release Date:2010 March 12
Default Enabled:True
Default Retired:False
Alarm Severity:Medium
Fidelity:100 

Description

Signature triggers on a TCP packet with a source port equal to 0 (zero).Port 0 is a reserved port, however it is not illegal. Traffic using a source port of 0 should be considered unusual or even suspicious and warrants further investigation.This could also be an attempt to fingerprint an OS or bypass firewall and router access controls.

Recommended Filter

There are no suggested filters.

Benign Triggers

There are no known benign triggers.

IntelliShield Alerts

IntelliShield ID Headline VersionCVSS ScoreLast Published
19935TCP/IP and UDP Network Traffic with a Source Port of 022010 March 15 12:31 GMT

Download

To download this and other IPS update files, please go to Cisco Secure Software Download.

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