db_nmap and db_import are glue commands between Nmap and Metasploit:
db_nmapis a wrapper around Nmap that inserts Nmap's results into the Metasploit PostgreSQL database, right after they are finished scanning.db_importis a standalone program that takes an Nmap result XML document and inserts the results into the Metasploit PostgreSQL daabase.
After importing the results, they can be inspected with the Metasploit console commands services and hosts.
Both commands are actually standalone implementations of the corresponding commands in Metasploit, which are documented here (db_nmap) and here (db_import).
On my local system, I am currently only running a PostgreSQL database (for Metasploit). I can scan localhost with the following command:
$ db_nmap -sV 127.0.0.1
INFO[2021-10-19 18:47:52] Connected to Metasploit PostgreSQL database "msf" at 127.0.0.1:5432 as user "jonas"
DEBU[2021-10-19 18:47:52] ID of Metasploit workspace "default": 1
DEBU[2021-10-19 18:47:52] Running "/usr/bin/nmap -sV 127.0.0.1 -oX /dev/fd/3" ...
Starting Nmap 7.92 ( https://nmap.org ) at 2021-10-19 18:47 CEST
Nmap scan report for localhost (127.0.0.1)
Host is up (0.0000040s latency).
Not shown: 999 closed tcp ports (reset)
PORT STATE SERVICE VERSION
5432/tcp open postgresql PostgreSQL DB 9.6.0 or later
1 service unrecognized despite returning data. [...]
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 6.48 seconds
DEBU[2021-10-19 18:47:59] Inserted/updated host 127.0.0.1 (localhost).
DEBU[2021-10-19 18:47:59] Inserted/updated service tcp:5432 (PostgreSQL DB).
DEBU[2021-10-19 18:47:59] XML document complete.
INFO[2021-10-19 18:47:59] Wrapper stats: registered 1 hosts with 1 services.
Note that db_nmap used the nmap command found in my PATH.
After scanning, the results can be retrieved from the Metasploit database:
$ msfconsole
[...]
msf6 > hosts -c address,name
Hosts
=====
address name
------- ----
127.0.0.1 localhost
msf6 > services
Services
========
host port proto name state info
---- ---- ----- ---- ----- ----
127.0.0.1 5432 tcp postgresql open PostgreSQL DB
Options, such as the database host, port, user and password can be passed through PostgreSQL's default environment variables documented here, e.g.:
$ PGUSER=metasploit PGPASSWORD=secret db_nmap -sV 127.0.0.1
In addition, the Metasploit workspace name can be set with the environment variable MSF_WORKSPACE (default: default):
$ MSF_WORKSPACE=project2 db_nmap -sV 127.0.0.1
The project is implemented in Go and can be built as follows:
go build ./cmd/db_nmap
go build ./cmd/db_import