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Cisco Security

TCP FRAG NULL Host Sweep

 
Signature ID: 3035/0
Original Release:S2
Release:S653 (download)
Original Release Date:2001 February 02
Latest Release Date:2012 June 25
Default Enabled:True
Default Retired:False
Alarm Severity:High
Fidelity:100 

Description

Triggers when a series of fragmented TCP packets with none of the SYN, FIN, ACK, or RST flags set have been sent to a number of different hosts on any port. This could, for example, be a sweep of many hosts to find out which ones can receive mail or telnet sessions. This is indicative that a reconnaissance sweep of your network may be in progress. This may be the prelude to a more serious attack. The use of this packet is abnormal, as is the use of fragmentation, and could indicate an attempt to conceal the sweep.

Recommended Filter

No recommended filters.

Benign Triggers

No known triggers.

IntelliShield Alerts

IntelliShield ID Headline VersionCVSS ScoreLast Published
123Port Sweep Activity12000 May 01 16:00 GMT

Download

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

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