Solved

Ports 137-139 security issue?

Posted on 2009-04-01
4
926 Views
Last Modified: 2013-12-04
One of our software vendors is installing an application on our web server and requests opening ports at our firewall (ASA) in order for the apps to run. Ports are 137-139 and 1433 bidirectional. Web server is located in dmz; I know those ports are considered as very unsecure but they did not give me any alternative. Also, the same ports needs to be opened to our email server which is in our LAN.
Now my question to all security experts: How high is the security risks?
thanks,
0
Comment
Question by:misd19
4 Comments
 
LVL 14

Expert Comment

by:theras2000
Comment Utility
Here's an article from Shields Up http://www.grc.com/port_137.htm
I don't know about what can be exploited through the port, so I guess I'm not answering your question, but it sounds bad.

I guess you want to know if it's absolutely necessary, and if so, then perhaps you could add some TCP/IP filtering to make sure you're only accepting traffic from their IP range.
For the email server, it would be a lot safer if you had a Front-End mail srever in the DMZ, and open the ports into that, rather than into your internal LAN.
0
 
LVL 23

Expert Comment

by:Admin3k
Comment Utility
The risk here is basically information disclosure, an attacker may be able to establish a Netbios  NULL session & enumerate lots of information from the server's registry including user names , share names ,etc.. 
if your server is a Windows 2003 machine , please try the below
Administrative Tools --> Local Security Policy --> Local Policies --> Security Options. enable those two policies
Network Access: Do not allow anonymous enumeration of SAM accounts: Enabled (Default)
Network Access: Do not allow anonymous enumeration of SAM accounts and shares: Enabled


This can also be  done using  through the below registry keys:
HKLM\System\CurrentControlSet\Control\Lsa\RestrictAnonymous=1 (This disallows enumeration of shares)
HKLM\System\CurrentControlSet\Control\Lsa\RestrictAnonymousSAM=1 (Default, not allowing enumeration of user accounts)


hope this helps.


0
 
LVL 38

Expert Comment

by:Rich Rumble
Comment Utility
If you do need to allow this access, make sure your firewall only allows one IP (or a few), do not open the ports to the internet at large...
If they cannot give you a fixed IP, you need a new vendor.
Vendor_IP 1.2.3.4 any port -> Your_IP 4.5.6.7 port 139

More preferable is a VPN connection, I suspect they have experience with one or both of these scenerios, so ask them how they communicate to their other customers. It's not a question you should of had to ask, they, the vendor should of informed you of a secure method of connecting, everyone knows what these ports are for. Frankly it doesn't matter what port they asked you to open, its the method of connection, if they mentioned VPN, good for them, if not shame on them. If they told you to open port xyand z, but failed to give you their own IP address or address space, then they messed up (possibly forgot to tell you?) or they don't care about security at all.
I hope they aren't providing security services ;)
-rich
0
 
LVL 4

Accepted Solution

by:
TurboBorland earned 500 total points
Comment Utility
If you are using Vista, I wouldn't be worried about it as it automatically requires authentication before use.

Null sessions are very old and hardly working anymore due to the havoc it had caused in the past.  Vista and beyond will not allow a default setup to have a null session created.

Even if you are to exploit this due to null session on old Windows operating systems, you are in a DMZ.  Only old worms will attempt to exploit this vulnerability.  All of which will be stopped by your malware signature database, if you use any malware detection tools.
0

Featured Post

Do You Know the 4 Main Threat Actor Types?

Do you know the main threat actor types? Most attackers fall into one of four categories, each with their own favored tactics, techniques, and procedures.

Join & Write a Comment

Today, still in the boom of Apple, PC's and products, nearly 50% of the computer users use Windows as graphical operating systems. If you are among those users who love windows, but are grappling to keep the system's hard drive optimized, then you s…
This story has been written with permission from the scammed victim, a valued client of mine – identity protected by request.
This demo shows you how to set up the containerized NetScaler CPX with NetScaler Management and Analytics System in a non-routable Mesos/Marathon environment for use with Micro-Services applications.
This video shows how to remove a single email address from the Outlook 2010 Auto Suggestion memory. NOTE: For Outlook 2016 and 2013 perform the exact same steps. Open a new email: Click the New email button in Outlook. Start typing the address: …

744 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

14 Experts available now in Live!

Get 1:1 Help Now