Nmap snmp-brute NSE Script
This page contains detailed information about how to use the snmp-brute NSE script. For list of all NSE scripts, visit the Nmap NSE Library.
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Script Overview
Script source code: https://github.com/nmap/nmap/tree/master/scripts/snmp-brute.nse
Script categories: intrusive, brute
Target service / protocol: snmp, udp
Target network port(s): 161
List of CVEs: -
Script Description
The snmp-brute.nse script attempts to find an SNMP community string by brute force guessing.
This script opens a sending socket and a sniffing pcap socket in parallel threads. The sending socket sends the SNMP probes with the community strings, while the pcap socket sniffs the network for an answer to the probes. If valid community strings are found, they are added to the creds database and reported in the output.
The script takes the snmp-brute.communitiesdb
argument that
allows the user to define the file that contains the community strings to
be used. If not defined, the default wordlist used to bruteforce the SNMP
community strings is nselib/data/snmpcommunities.lst
. In case
this wordlist does not exist, the script falls back to
nselib/data/passwords.lst
No output is reported if no valid account is found.
Snmp-brute NSE Script Arguments
This is a full list of arguments supported by the snmp-brute.nse script:
snmp-brute.communitiesdbThe filename of a list of community strings to try.
creds.globalCredentials to be returned by Credentials.getCredentials regardless of the service.
creds.[service]Credentials to be returned by Credentials.getCredentials for [service]. E.g. creds.http=admin:password
creds.[service]Credentials to be returned by Credentials.getCredentials for [service]. E.g. creds.http=admin:password
snmp.version
The SNMP protocol version. Use "v1"
or 0
for SNMPv1 (default) and "v2c"
or 1
for SNMPv2c.
The filename of an alternate password database. Default: nselib/data/passwords.lst
unpwdb.passlimit
The maximum number of passwords passwords
will return (default unlimited).
The maximum amount of time that any iterator will run before stopping. The value is in seconds by default and you can follow it with ms
, s
, m
, or h
for milliseconds, seconds, minutes, or hours. For example, unpwdb.timelimit=30m
or unpwdb.timelimit=.5h
for 30 minutes. The default depends on the timing template level (see the module description). Use the value 0
to disable the time limit.
The maximum number of usernames usernames
will return (default unlimited).
The filename of an alternate username database. Default: nselib/data/usernames.lst
- - -
To use these script arguments, add them to the Nmap command line using the --script-args arg1=value,[arg2=value,..]
syntax. For example:
nmap --script=snmp-brute --script-args snmp-brute.communitiesdb=value,creds.global=value <target>
Snmp-brute NSE Script Example Usage
Here's an example of how to use the snmp-brute.nse script:
nmap -sU --script snmp-brute <target> [--script-args snmp-brute.communitiesdb=<wordlist> ]
Snmp-brute NSE Script Example Output
Here's a sample output from the snmp-brute.nse script:
PORT STATE SERVICE
161/udp open snmp
| snmp-brute:
| dragon - Valid credentials
|_ jordan - Valid credentials
Snmp-brute NSE Script Example XML Output
There is no sample XML output for this module. However, by providing the -oX <file>
option, Nmap will produce a XML output and save it in the file.xml
file.
Authors
- Philip Pickering
- Gorjan Petrovski
- Patrik Karlsson
- Gioacchino Mazzurco
References
- https://nmap.org/nsedoc/scripts/snmp-brute.html
- https://github.com/nmap/nmap/tree/master/scripts/snmp-brute.nse
See Also
Related NSE scripts to the snmp-brute.nse script:
- snmp-hh3c-logins.nse
- snmp-info.nse
- snmp-interfaces.nse
- snmp-ios-config.nse
- snmp-netstat.nse
- snmp-processes.nse
- snmp-sysdescr.nse
- snmp-win32-services.nse
- snmp-win32-shares.nse
- snmp-win32-software.nse
- snmp-win32-users.nse
Visit Nmap NSE Library for more scripts.
The snmp-brute.nse script may fail with the following error messages. Check for the possible causes by using the code snippets highlighted below found in the script source code. This can often times help in identifying the root cause of the problem.
Cannot find communities list
Here is a relevant code snippet related to the "Cannot find communities list" error message:
97: end
98: end
99:
100: local communities_raw = function(path)
101: if not path then
102: return false, "Cannot find communities list"
103: end
104:
105: if not filltable(path, communitiestable) then
106: return false, "Error parsing communities list"
107: end
Error parsing communities list
Here is a relevant code snippet related to the "Error parsing communities list" error message:
101: if not path then
102: return false, "Cannot find communities list"
103: end
104:
105: if not filltable(path, communitiestable) then
106: return false, "Error parsing communities list"
107: end
108:
109: return true, closure(communitiestable)
110: end
111:
Cannot read the communities file, using the nmap username/password database instead
Here is a relevant code snippet related to the "Cannot read the communities file, using the nmap username/password database instead" error message:
129: count_limit = tonumber(stdnse.get_script_args("unpwdb.passlimit"))
130: end
131:
132: return true, unpwdb.limited_iterator(iterator, time_limit, count_limit, "communities")
133: else
134: stdnse.debug1("Cannot read the communities file, using the nmap username/password database instead")
135:
136: return unpwdb.passwords()
137: end
138: end
139:
Could not send SNMP probe
Here is a relevant code snippet related to the "Could not send SNMP probe" error message:
153: end
154: payload = snmp.encode(snmp.buildPacket(request, nil, community))
155: status, err = socket:send(payload)
156: if not status then
157: result.status = false
158: result.msg = "Could not send SNMP probe"
159: condvar "signal"
160: return
161: end
162:
163: community = nextcommunity()
Failed to read the communities database
Here is a relevant code snippet related to the "Failed to read the communities database" error message:
229:
230: action = function(host, port)
231: local status, nextcommunity = communities()
232:
233: if not status then
234: return fail("Failed to read the communities database")
235: end
236:
237: local result = {}
238: local threads = {}
239:
Failed to connect to server
Here is a relevant code snippet related to the "Failed to connect to server" error message:
246:
247: local socket = nmap.new_socket("udp")
248: status = socket:connect(host, port)
249:
250: if ( not(status) ) then
251: return fail("Failed to connect to server")
252: end
253:
254: local status, _, lport = socket:get_info()
255: if( not(status) ) then
256: return fail("Failed to retrieve local port")
Failed to retrieve local port
Here is a relevant code snippet related to the "Failed to retrieve local port" error message:
251: return fail("Failed to connect to server")
252: end
253:
254: local status, _, lport = socket:get_info()
255: if( not(status) ) then
256: return fail("Failed to retrieve local port")
257: end
258:
259: local recv_co = stdnse.new_thread(sniff_snmp_responses, host, port, lport, result)
260: local send_co = stdnse.new_thread(send_snmp_queries, socket, result, nextcommunity)
261:
An error occurred:
Here is a relevant code snippet related to the "An error occurred: " error message:
268: if recv_dead then break end
269: end
270:
271: socket:close()
272:
273: if result.status then
274: return creds.Credentials:new(SCRIPT_NAME, host, port):getTable()
275: else
276: stdnse.debug1("An error occurred: "..result.msg)
277: end
278: end
Version
This page has been created based on Nmap version 7.92.
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