HIGH: Open NetBIOS Report

DESCRIPTION LAST UPDATED: 2023-12-28

DEFAULT SEVERITY LEVEL: HIGH

This report identifies hosts that have the NetBIOS service running and accessible on the Internet.

These services have the potential to be used in amplification attacks by criminals that wish to perform denial of service attacks.

The analogous shell command (from a windows box) to identify these hosts would be:

nbtstat -A [ip]

You can track the latest NetBIOS exposure on the Dashboard.

Severity levels are described here.

For more information on our scanning efforts, check out our Internet scanning summary page..

Filenames: scan_netbios

Fields

  • timestamp
    Time that the IP was probed in UTC+0
  • severity
    Severity level
  • ip
    The IP address of the device in question
  • protocol
    Protocol that the DNS response came on (usually UDP)
  • port
    Port that the NetBIOS response came from
  • hostname
    Reverse DNS name of the device in question
  • tag
    Will always be netbios
  • mac_address
    The media access control (MAC) address that NetBIOS reports that the probed host is using
  • asn
    ASN of where the device in question resides
  • geo
    Country where the device in question resides
  • region
    State / Province / Administrative region where the device in question resides
  • city
    City in which the device in question resides
  • workgroup
    The reported workgroup / domain name that the probed host belongs to
  • machine_name
    The reported NetBIOS name that the probed host is using
  • username
    The possible user that is logged into the probed host
  • hostname_source
    Hostname source
  • naics
    North American Industry Classification System Code
  • sector
    Sector the IP belongs to
  • response_size
    Response size in bytes
  • amplification
    Amplification factor (This amplification is is based solely on the payload size sent and payload size received)

Sample

"timestamp","severity","ip","protocol","port","hostname","tag","mac_address","asn","geo","region","city","workgroup","machine_name","username","naics","hostname_source","sector","response_size","amplification"
"2010-02-10 00:00:00",high,192.168.0.1,udp,137,node01.example.com,netbios,00-00-00-00-00-00,64512,ZZ,Region,City,WORKGROUP,node01,SC-LVG,0,ptr,,229,4.58
"2010-02-10 00:00:01",high,192.168.0.2,udp,137,node02.example.com,netbios,00-14-22-09-99-C4,64512,ZZ,Region,City,WORKGROUP,node02,,0,ptr,,211,4.22
"2010-02-10 00:00:02",high,192.168.0.3,udp,137,node03.example.com,netbios,22-41-6C-02-00-69,64512,ZZ,Region,City,WORKGROUP,node03,,0,,,157,3.14

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