[Snort-sigs] SID 371 (my contribution #6)

Steven Alexander alexander.s at ...1565...
Mon Jun 9 09:40:18 EDT 2003

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alert icmp $EXTERNAL_NET any -> $HOME_NET any (msg:"ICMP PING Cisco
Type.x"; content:"|abcdabcdabcdabcdabcdabcdabcdabcd|";itype:8;depth:32;
reference:arachnids,153; sid:371; classtype:misc-activity; rev:4;) 



ping is a standard networking utility that determines if a target host
is up. This rule indicates that the ping originated from a router
running Cisco 9.x.


Can be used as a reconnaissance tool.

Detailed Information:

ping sends an ICMP Echo Request packet to an IP address.  If a host is
up at that address it will reply with an ICMP Echo Reply.  The reply
includes the data portion of the echo packet.  The data included in the
Echo Request varies across different implementations.

Affected Systems:

Attack Scenarios:

An attacker will often ping a machine to make sure it is up before

Ease of Attack:
Very Simple

False Positives:
This program is also used legitimately by users and/or network
administrators to troubleshoot problems.  It is possible to emulate this
ping signature using another ping utility.

False Negatives:

None known.
Corrective Action:

ICMP packets can be blocked with a firewall.

Documentation - Steven Alexander<alexander.s at ...1565...>
Additional References:


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