Script dns-random-txid

Script types: portrule
Categories: external, intrusive
Download: https://svn.nmap.org/nmap/scripts/dns-random-txid.nse

Script Summary

Checks a DNS server for the predictable-TXID DNS recursion vulnerability. Predictable TXID values can make a DNS server vulnerable to cache poisoning attacks (see CVE-2008-1447).

The script works by querying txidtest.dns-oarc.net (see https://www.dns-oarc.net/oarc/services/txidtest). Be aware that any targets against which this script is run will be sent to and potentially recorded by one or more DNS servers and the txidtest server. In addition your IP address will be sent along with the txidtest query to the DNS server running on the target.

Example Usage

nmap -sU -p 53 --script=dns-random-txid <target>

Script Output

PORT   STATE SERVICE REASON
53/udp open  domain  udp-response
|_dns-random-txid: X.X.X.X is GREAT: 27 queries in 61.5 seconds from 27 txids with std dev 20509

Requires

• comm
• nmap
• shortport
• string
• stdnse

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Author:

• Script: Brandon Enright <bmenrigh@ucsd.edu> txidtest.dns-oarc.net: Duane Wessels <wessels@dns-oarc.net>

License: Same as Nmap--See https://nmap.org/book/man-legal.html