Nmap ssl-known-key NSE Script
This page contains detailed information about how to use the ssl-known-key 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/ssl-known-key.nse
Script categories: safe, discovery, vuln, default
Target service / protocol: ssl
Target network port(s): 261, 271, 324, 443, 465, 563, 585, 636, 853, 989, 990, 992, 993, 994, 995, 2221, 2252, 2376, 3269, 3389, 4911, 5061, 5986, 6679, 6697, 8443, 9001, 8883
List of CVEs: -
Script Description
The ssl-known-key.nse script checks whether the SSL certificate used by a host has a fingerprint that matches an included database of problematic keys.
The only databases currently checked are the LittleBlackBox 0.1 database of compromised keys from various devices, some keys reportedly used by the Chinese state-sponsored hacking division APT1 (https://www.fireeye.com/blog/threat-research/2013/03/md5-sha1.html), and the key used by CARBANAK malware (https://www.fireeye.com/blog/threat-research/2017/06/behind-the-carbanak-backdoor.html). However, any file of fingerprints will serve just as well. For example, this could be used to find weak Debian OpenSSL keys using the widely available (but too large to include with Nmap) list.
Ssl-known-key NSE Script Arguments
This is a full list of arguments supported by the ssl-known-key.nse script:
ssl-known-key.fingerprintfileSpecify a different file to read fingerprints from.
smbdomainThe domain to log in with. If you aren't in a domain environment, then anything will (should?) be accepted by the server.
smbhashA password hash to use when logging in. This is given as a single hex string (32 characters) or a pair of hex strings (both 32 characters, optionally separated by a single character). These hashes are the LanMan or NTLM hash of the user's password, and are stored on disk or in memory. They can be retrieved from memory using the fgdump or pwdump tools.
smbnoguestUse to disable usage of the 'guest' account.
smbpasswordThe password to connect with. Be cautious with this, since some servers will lock accounts if the incorrect password is given. Although it's rare that the Administrator account can be locked out, in the off chance that it can, you could get yourself in trouble. To use a blank password, leave this parameter off altogether.
smbtypeThe type of SMB authentication to use. These are the possible options:
v1
: Sends LMv1 and NTLMv1.LMv1
: Sends LMv1 only.NTLMv1
: Sends NTLMv1 only (default).v2
: Sends LMv2 and NTLMv2.LMv2
: Sends LMv2 only.NTLMv2
: Doesn't exist; the protocol doesn't support NTLMv2 alone. The default,NTLMv1
, is a pretty decent compromise between security and compatibility. If you are paranoid, you might want to usev2
orlmv2
for this. (Actually, if you're paranoid, you should be avoiding this protocol altogether!). If you're using an extremely old system, you might need to set this tov1
orlm
, which are less secure but more compatible. For information, seesmbauth.lua
.
The SMB username to log in with. The forms "DOMAIN\username" and "username@DOMAIN" are not understood. To set a domain, use the smbdomain
argument.
Set to a value to change the filenames/service names that are randomly generated.
smbbasicForces the authentication to use basic security, as opposed to "extended security". Against most modern systems, extended security should work, but there may be cases where you want to force basic. There's a chance that you'll get better results for enumerating users if you turn on basic authentication.
smbport
Override the default port choice. If smbport
is open, it's used. It's assumed to be the same protocol as port 445, not port 139. Since it probably isn't possible to change Windows' ports normally, this is mostly useful if you're bouncing through a relay or something.
Controls whether or not server signatures are checked in SMB packets. By default, on Windows, server signatures aren't enabled or required. By default, this library will always sign packets if it knows how, and will check signatures if the server says to. Possible values are:
force
: Always check server signatures, even if server says it doesn't support them (will Probably fail, but is technically more secure).negotiate
: [default] Use signatures if server supports them.ignore
: Never check server signatures. Not recommended.disable
: Don't send signatures, at all, and don't check the server's. not recommended. More information on signatures can be found insmbauth.lua
.
The domain against which to perform integrated authentication. When set, the scripts assume integrated authentication should be performed, rather than the default sql login.
mssql.instance-allTargets all SQL server instances discovered through the browser service.
mssql.instance-nameThe name of the instance to connect to.
mssql.instance-portThe port of the instance to connect to.
mssql.password
The password for mssql.username
. If this argument is not given but mssql.username
, a blank password is used.
The protocol to use to connect to the instance. The protocol may be either NP
,Named Pipes
or TCP
.
If set, the script will only connect to ports that were included in the Nmap scan. This may result in instances not being discovered, particularly if UDP port 1434 is not included. Additionally, instances that are found to be running on ports that were not scanned (e.g. if 1434/udp is in the scan and the SQL Server Browser service on that port reports an instance listening on 43210/tcp, which was not scanned) will be reported but will not be stored for use by other ms-sql-* scripts.
mssql.timeout
How long to wait for SQL responses. This is a number followed by ms
for milliseconds, s
for seconds, m
for minutes, or h
for hours. Default: 30s
.
The username to use to connect to SQL Server instances. This username is used by scripts taking actions that require authentication (e.g. ms-sql-query
) This username (and its associated password) takes precedence over any credentials discovered by the ms-sql-brute
and ms-sql-empty-password
scripts.
The domain to be returned by get_domain, overriding the target's own domain name.
tls.servernameHostname to use in the Server Name Indication (SNI) extension. Overrides the target name given on the command line and affects all targets.
- - -
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=ssl-known-key --script-args ssl-known-key.fingerprintfile=value,smbdomain=value <target>
Ssl-known-key NSE Script Example Usage
Here's an example of how to use the ssl-known-key.nse script:
nmap --script ssl-known-key -p 443 <host>
Ssl-known-key NSE Script Example Output
Here's a sample output from the ssl-known-key.nse script:
PORT STATE SERVICE REASON
443/tcp open https syn-ack
|_ssl-known-key: Found in Little Black Box 0.1 (SHA-1: 0028 e7d4 9cfa 4aa5 984f e497 eb73 4856 0787 e496)
Ssl-known-key NSE Script Example XML Output
Here's a sample XML output from the ssl-known-key.nse script produced by providing the -oX <file>
Nmap option:
<table>
<elem key="section">Little Black Box 0.1</elem>
<elem key="sha1">0028e7d49cfa4aa5984fe497eb7348560787e496</elem>
</table>
Author
- Mak Kolybabi
References
- https://nmap.org/nsedoc/scripts/ssl-known-key.html
- https://github.com/nmap/nmap/tree/master/scripts/ssl-known-key.nse
- https://www.fireeye.com/blog/threat-research/2013/03/md5-sha1.html
- https://www.fireeye.com/blog/threat-research/2017/06/behind-the-carbanak-backdoor.html
See Also
Related NSE scripts to the ssl-known-key.nse script:
- ssl-ccs-injection.nse
- ssl-cert-intaddr.nse
- ssl-cert.nse
- ssl-date.nse
- ssl-dh-params.nse
- ssl-enum-ciphers.nse
- ssl-heartbleed.nse
- ssl-poodle.nse
- sslv2-drown.nse
- sslv2.nse
Visit Nmap NSE Library for more scripts.
The ssl-known-key.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.
Failed to open file
Here is a relevant code snippet related to the "Failed to open file " error message:
60: stdnse.debug2("Loading SSL fingerprints from %s.", full_path)
61:
62: -- Open database.
63: local file = io.open(full_path, "r")
64: if not file then
65: return false, "Failed to open file " .. full_path
66: end
67:
68: -- Parse database.
69: local section = nil
70: local fingerprints = {}
Cannot parse presumed fingerprint %q in section %q.
Here is a relevant code snippet related to the "Cannot parse presumed fingerprint %q in section %q." error message:
83: local fingerprint = stdnse.fromhex(line)
84: if #fingerprint == 20 then
85: fingerprints[fingerprint] = section
86: stdnse.debug4("Added key %s to database.", line)
87: else
88: stdnse.debug0("Cannot parse presumed fingerprint %q in section %q.", line, section)
89: end
90: else
91: -- Key found outside of section.
92: stdnse.debug1("Key %s is not in a section.", line)
93: end
sslcert.getCertificate error: %s
Here is a relevant code snippet related to the "sslcert.getCertificate error: %s" error message:
117: local fingerprints = result
118:
119: -- Get SSL certificate.
120: local status, cert = sslcert.getCertificate(host, port)
121: if not status then
122: stdnse.debug1("sslcert.getCertificate error: %s", cert)
123: return
124: end
125: local fingerprint = cert:digest("sha1")
126: local fingerprint_fmt = stdnse.tohex(fingerprint, {separator=" ", group=4})
127:
Version
This page has been created based on Nmap version 7.92.
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