nbtscan - NETBIOS nameserver scanner
This is a command-line tool that scans for open NETBIOS nameservers on a
local or remote TCP/IP network, and this is a first step in finding of
open shares. It is based on the functionality of the standard Windows
tool nbtstat, but it operates on a range of addresses instead
of just one. I wrote this tool because the existing tools either didn't
do what I wanted or ran only on the Windows platforms: mine runs on just
about everything.
NETBIOS is commonly known as the Windows "Network Neighborhood" protocol,
and (among other things), it provides a nameservice that listens on UDP
port 137. When it receives a query on this port, it responds with a list
of all services it offers. Windows ships with a standard tool nbtstat
which queries a single IP address when given the -A parameter. When
run against a machine on the local network (a development box), it shows:
C:\> nbtstat -A 192.168.1.99
NetBIOS Remote Machine Name Table
Name Type Status
---------------------------------------------
XPDEV <00> UNIQUE Registered
UNIXWIX <00> GROUP Registered
XPDEV <03> UNIQUE Registered
XPDEV <20> UNIQUE Registered
UNIXWIX <1E> GROUP Registered
MAC Address = 00-50-04-6D-50-37The numeric code (in hexadecimal) and the type serve to identify the service being offered, and (for instance) a UNIQUE code of <20> indicates that the machine is running the file-sharing service. Unfortunately, nbtstat only reports the codes, and it requires looking up the meanings elsewhere. The References section at the end of this document lists some resources to learn what all the codes mean.
Machines participating in NETBIOS listen on UDP port
137 for these queries and respond accordingly. Simple configurations
might only have a few resource records (as above), but an NT server
supporting a large enterprise could easily have more than a dozen.
Though it's sometimes useful to examine the full set of resource records
for a given machine, in practice it's more useful to summarize them into
the key "interesting" services.
Our tool has taken this approach. Not only does it scan ranges
of addresses -- instead of just one machine -- but it can fully decode
most of the resource record types and can summarize the interesting
data on a one-line display.
On our network we have quite a few machines, but it appears
that only three respond to our queries:
C:\> nbtscan 192.168.1.0/24
192.168.1.3 MTNDEW\WINDEV SHARING DC
192.168.1.5 MTNDEW\TESTING
192.168.1.9 MTNDEW\WIZ SHARING U=STEVE
192.168.1.99 MTNDEW\XPDEV SHARING
nbtscan - NETBIOS nameserver scanner
Reviewed by Zion3R
on
9:54 PM
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Reviewed by Zion3R
on
9:54 PM
Rating:
