Nmap Development mailing list archives
Re: what did I miss this time?
From: Kris Katterjohn <kjak () ispwest com>
Date: Sat, 26 Aug 2006 11:37:13 -0500
Omar Herrera wrote:
Nmap's ping is distinguishable from other tools. It sends an ICMP Echo Request package with no data. Here are 2 examples of 2 captured ICMP packets with Wireshark. The first is from a Windows ping and the second is from nmap 4.11 (Windows version, but it has the same behaviour in Linux as far as I know): --- No. Time Source Destination Protocol Info 1 16:42:59 sss.sss.sss.sss ddd.ddd.ddd.ddd ICMP Echo (ping) request Frame 1 (74 bytes on wire, 74 bytes captured) Ethernet II, Src: Actionte_52:3b:21 (00:0f:b3:52:3b:21), Dst: NICBrand_xx:xx:xx (xx:xx:xx:xx:xx:xx) Internet Protocol, Src: sss.sss.sss.sss (sss.sss.sss.sss), Dst: ddd.ddd.ddd.ddd (ddd.ddd.ddd.ddd) Internet Control Message Protocol Type: 8 (Echo (ping) request) Code: 0 Checksum: 0x425c [correct] Identifier: 0x0500 Sequence number: 0x0600 Data (32 bytes) 0000 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f 70 abcdefghijklmnop 0010 71 72 73 74 75 76 77 61 62 63 64 65 66 67 68 69 qrstuvwabcdefghi No. Time Source Destination Protocol Info 2 16:43:14 sss.sss.sss.sss ddd.ddd.ddd.ddd ICMP Echo (ping) request Frame 2 (42 bytes on wire, 42 bytes captured) Ethernet II, Src: Actionte_52:3b:21 (00:0f:b3:52:3b:21), Dst: NICBrand_xx:xx:xx (xx:xx:xx:xx:xx:xx) Internet Protocol, Src: sss.sss.sss.sss (sss.sss.sss.sss), Dst: ddd.ddd.ddd.ddd (ddd.ddd.ddd.ddd) Internet Control Message Protocol Type: 8 (Echo (ping) request) Code: 0 Checksum: 0xa564 [correct] Identifier: 0xcb78 Sequence number: 0x8722 --- This has been known for a long time. There are also snort rules to block nmap's ping: For example (reference: http://www.iu.hio.no/teaching/materials/MS004A/index.phtml?show=P90.en&week= 11): drop icmp $HONEYNET any -> $EXTERNAL_NET any (msg:"ICMP PING NMAP"; dsize: 0; itype: 8; reference:arachnids,162; classty pe:attempted-recon; sid:469; rev:1;) Regards, Omar Herrera-----Original Message----- From: nmap-dev-bounces () insecure org [mailto:nmap-dev-bounces () insecure org] I finally got a chance to test this with FreeBSD (nmap 4.01) and guess what, it doesn't work for this one host. Regular ping works. so I am forced to assume this host is able to differentiate between a normal ping and an nmap echo request ping. Is this possible ?? thanks.
Just glancing at the code I noticed that nmap sent it with no data, but I wasn't sure enough about that being the reason to say it. Thanks for the overview. Kris Katterjohn _______________________________________________ Sent through the nmap-dev mailing list http://cgi.insecure.org/mailman/listinfo/nmap-dev Archived at http://SecLists.Org
Current thread:
- what did I miss this time? R M (Aug 25)
- Re: what did I miss this time? Kris Katterjohn (Aug 25)
- Re: what did I miss this time? R M (Aug 25)
- Re: what did I miss this time? R M (Aug 26)
- RE: what did I miss this time? Omar Herrera (Aug 26)
- Re: what did I miss this time? Kris Katterjohn (Aug 26)
- Re: what did I miss this time? R M (Aug 27)
- Re: what did I miss this time? Fyodor (Aug 28)
- Re: what did I miss this time? R M (Aug 29)
- Re: what did I miss this time? R M (Aug 25)
- Re: what did I miss this time? Kris Katterjohn (Aug 25)