Snort mailing list archives
Re: arp spoof
From: Jeff Nathan <jeff () snort org>
Date: Fri, 28 Jun 2002 12:50:56 -0700
john wrote:
hi everybody i am new in using snort , when i read the arpspoof preprocessor i cant
understand its role from those brief words in the snort.conf file is here another way to learn more about it and the other preprocessors other than snort manual
any help is appreciated.........
(Thanks for replying first Mr. Sage!) Essentially, spp_arpspoof has 4 detection mechanisms. (The following two methods address the use of 'preprocessor arpspoof' in snort.conf) First: If an ARP request is observed, the source hardware address in the Ethernet frame is compared to the sender Ethernet address in the ARP packet. If there is a mismatch an alert is generated. Second: If an ARP reply is observed, the source hardware address in the Ethernet frame is compared to the sender Ethernet address in the ARP paclet. Also, the destination hardware address in the Ethernet frame is compared to the target Ethernet address within the ARP packet. If there is a mismatch in either of the two pairs of fields compared, an alert is generated. (The following method addresses the use of 'preprocessor arpspoof: -unicast' in snort.conf) Third: If an ARP request is observed where the destination Ethernet address in the Ethernet header is not the broadcast address (FF:FF:FF:FF:FF:FF), an alert is generated. (The following method addresses the use of 'arpspoof_detect_host: 192.168.40.1 f0:0f:00:f0:0f:00' in snort.conf) Fourth: A list of IP address/MAC address pairs is created in memory. If the sender IP address within the ARP frame matches an entry in snort's list, the MAC address in snort's list is compared to fields within the Ethernet header and ARP request packet. If either the source Ethernet address within the Ethernet header OR the sender Ethernet address within the ARP packet does not match the entry in snort's list, an alert is generated. This test is performed on both ARP requests and replies. Chapter 4 of TCP/IP Illustrated volume 1 is very helpful when learning about ARP. I hope this addresses your questions. -Jeff -- http://jeff.wwti.com (pgp key available) "Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Caffeinated soap. No kidding. http://thinkgeek.com/sf _______________________________________________ Snort-users mailing list Snort-users () lists sourceforge net Go to this URL to change user options or unsubscribe: https://lists.sourceforge.net/lists/listinfo/snort-users Snort-users list archive: http://www.geocrawler.com/redir-sf.php3?list=snort-users
Current thread:
- arp spoof john (Jun 27)
- Re: arp spoof John Sage (Jun 28)
- Re: arp spoof Jeff Nathan (Jun 28)