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Port 137 Details
known port assignments and vulnerabilities
threat/application/port search:
| Port(s) |
Protocol |
Service |
Details |
Source |
| 137 |
tcp,udp |
netbios-ns |
NetBIOS is a protocol used for File and Print Sharing under all current versions of Windows. While this in itself is not a problem, the way that the protocol is implemented can be.
NetBios services:
NETBIOS Name Service (TCP/UDP: 137)
NETBIOS Datagram Service (TCP/UDP: 138)
NETBIOS Session Service (TCP/UDP: 139)
By default, when File and Print Sharing is enabled it binds to everything, including TCP/IP (The Internet Protocol), rather than just the local network, meaning your shared resources are available over the entire Internet for reading and deletion, unless configured properly. Any machine with NetBIOS enabled and not configured properly should be considered at risk. The best protection is to turn off File and Print Sharing, or block ports 135-139 completely. If you must enable it, use the following guidelines:
1. Use strong passwords, containing non-alphanumeric characters.
2. Attach "$" at the end of your share names (the casual snooper using net view might not see them).
3. Unbind File and Print Sharing from TCP/IP and use NetBEUI instead (it's a non-routable protocol).
4. Block ports 135-139 in your router/firewall.
Keep in mind that you might still be leaking out information about your system that can be used against you (such as your computer and workgroup names) to the entire Internet, unless ports are filtered by a firewall.
There is also a Critical Windows RPC vulnerability affecting ports 135,139 and 445, as detailed here: MS Technet Security Bulletin [MS03-026]
The following trojans/backdoors also use these ports: Chode, God Message worm, Msinit, Netlog, Network, Qaz
W32.HLLW.Moega [Symantec-2003-080813-3234-99] (2003.08.08) - worm with backdoor capabilities, opens TCP ports 139 and 445.
W32.Crowt.A@mm [Symantec-2005-012310-2158-99] (2005.01.23) - mass mailing worm, opens a backdoor, logs keystrokes. Uses ports 80 and 137.
W32.Reidana.A [Symantec-2005-032515-4042-99] (2005.03.27) - worm that spreads using the MS DCOM RPC vulnerability (MS Security Bulletin [MS03-026]) on port 139. The worm attempts to download and execute a remote file via FTP. Opens TCP port 4444.
Windows Internet Naming Service (WINS) also uses this port (UDP).
Sygate Personal Firewall comes with a default rule set that blocks all udp requests, however if udp requests originates from source port 137 or 138 they are allowed, thus a malicious person could get access to all open udp ports on a target merely by sending all requests from source port 137 or 138.
References: [SECUNIA-7930] |
SG
|
| 137 |
tcp,udp |
|
NetBIOS NetBIOS Name Service (official) |
Wikipedia
|
| 137 |
tcp |
trojan |
Chode, Nimda |
Trojans
|
| 137 |
udp |
trojan |
Bugbear, Msinit, Opaserv, Qaz |
Trojans
|
| 137 |
tcp |
Chode |
[trojan] Chode |
Neophasis
|
| 137 |
tcp |
Qaz |
[trojan] Qaz |
Neophasis
|
| 137 |
udp |
Msinit |
[trojan] Msinit |
Neophasis
|
| 137 |
udp |
threat |
Femot |
Bekkoame
|
| 137 |
udp |
threat |
Msinit |
Bekkoame
|
| 137 |
tcp |
threat |
Chode |
Bekkoame
|
| 137 |
tcp,udp |
netbios-ns |
NETBIOS Name Service |
IANA
|
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11 records found
Related ports: 135 138 139 445
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