Stopping NetBIOS Spam? 97
MoonFacedAssassin asks: "I woke up this morning to find that my computer had a Windows messaging pop-up window with an advertisement about getting diplomas and degrees. I was quite shocked to find that my Bellsouth DSL IP address had been spammed. Has this happened to anyone else? Other than closing off the port which this can come through, are there any other ways to block this spam? And, how responsible is Bellsouth (or any ISP for that matter) in handling issues like this?"
um. (Score:4, Insightful)
Seems to me that restricting the port would be the sane method of preventing outside persons from exploiting your system. The same as any other service on any other port.
Re:um. (Score:5, Informative)
I concur with you danielrose [mailto].
<RANT> Without denying MoonFacedAssassin [mailto] the right to a response to a very pertinent question, I think that posting that on Ask SlashJeeves [slashdot.org] shows a suprising level of ignorance from Cliff. Or he is at the end of some coding spree? Because this question does dot belong here, but rather on some newsgroup like comp.security.firewall (someone help me there).
Anyway, let me end my RANT section by saying that the level of interest of ask slashdot has regularly reached new lows every day.
I'm worried, to say the least
But let's drop the political/marketing aspect of that and take car of some real technical stuff:
Believe me, I've got firsthand experiences of having systems simply plug onto the internet, not even having some DNS record, and beeing scanned after one days of routable IP presence.
And no, you don't want them to "protect" you from that, because if they start going big brother on you, you will notice a real drop on the number of things you can do online. Unless you really want only to surf and e-mail a bit, that will be perfectly understandable.
But that's another debate: since internet is a jungle now, do we want to see some new kind of ISP that babysits theyr not-so-technical users ?
I'm not trying to scare you there, it`s just a fact.
In this case, please unplug from the network and reinstall from scratch. Do not backup any executablte. And the first time you re-plug you machine on the internet, please go immediately shopping for a personnal firewall, like ZoneAlarm and such. Once this one is done, either make sure your anti-virus software is up to date, or get you one. This will give you a reasonnable amount of security.
Re:um. (Score:4, Insightful)
you are right, unbind netbios (Score:2)
NT4: control panel -> network -> services -> services, just make sure under your internet ip (dail up adpater) nothing else then tcp/ip is checked.
win2000: network -> make sure only tcp/ip is checked.
Stopping the messager services will stop the spam, an leaves your PC open to the internet. But it helps against BOFH.
Re:um. (Score:1)
Re:um. (Score:2, Informative)
Re:um. (Score:2)
Re:um. (Score:1)
Re:um. (Score:1)
Well, just to settle (probably too late) that dispute:
Now, if you have a cable modem that is not using PPPOE but DHCP (my case), then this is obviously not a valide netmask (mine is 255.255.255.0).
Go read any TCP/IP and networking-related howto and come back, guys !
Re:um. (Score:1)
Re:um. (Score:2)
We've got that already. It's called AOL.
-"Zow"
Re:um. (Score:1, Funny)
What, they don't have AOL where you're from? ^_^
Overlooking the obvious (Score:1, Troll)
Re:Overlooking the obvious (Score:5, Insightful)
Re:Overlooking the obvious (Score:3, Insightful)
A good start would be a decent software firewall. Tiny Software used to offer theirs for free for personal use, but seem to have taken it down from their website =(. If you scour the net, you might be able to find it for download from one of those shareware sites.
A reinstall also would be prudent. When I'm doing a fresh install I try to keep the machine behind a device doing NAT until I have proper firewall software installed and my box patched.
Re:Overlooking the obvious (Score:1)
Shut it down? (Score:2, Informative)
I believe shutting down the messenger service will stop them.
Re:Shut it down? (Score:2, Interesting)
That's worse than a band-aid for a broken arm, we're into tumor land here.
Re:Shut it down? (Score:2)
This is why firewalls exist. Block all, allow some. For starters, block ports 135 and 137:139. These are ports that have been so readily available, and so frequently abused that many major broabdand ISPs in North America have taken to blocking them at all client access points.
These SPAMmers, if anything, are doing people a FAVOUR , and my point was simply that instead of stopping the 'annoying message', you could take it appropriately as a 'heads up' to the fact that you are running a vulnerable system and do something about it.
I apologize if some of you consider statement of the obvious as flamebait, but I gess as they say 'Common sense isn't very common.'
stop the service (Score:3, Informative)
HOW TO stop the service (Score:2)
NET STOP MESSENGER
To make sure it doesn't restart next time you reboot, go into Control Panel, find the Services applet. Set the Messenger service to startup settings of "Manual" or "Disabled" (as opposed to "Automatic" which restarts it at every boot).
That works for NT, 2000 and XP. If you are still running 95/98/Me, then may god have mercy on your soul.
Re:HOW TO stop the service (Score:2)
PS - See my other post about why this is not a good idea.
Re:HOW TO stop the service (Score:2)
Firewall yourself... (Score:5, Informative)
Basically, they're port scanning for open port 139s and spam IP that comes up positive. Either turn off the messenger service in services or install a firewall/router and block incoming tcp connections on port 139 (NetBIOS).
While you're at it, turn off the remote registry service...
Re:Firewall yourself... (Score:1)
You said it yourself... (Score:5, Insightful)
As for the second part, you cannot count on an ISP's usage terms to protect you from malicious acts. For good or for bad, they sell access services, not security services.
Re:You said it yourself... (Score:2)
I wish I could pop up a message on their screens. Something polite and respectful like 'piss off you little bastard'.
Re:You said it yourself... (Score:3, Funny)
net send ipnumber "your message"
It's implemented in samba too. Eiter in smbsend or smbclient. Look it up if you need it.
Re:You said it yourself... (Score:2)
PS: Funny?
Re:You said it yourself... (Score:5, Interesting)
>screens. Something polite and respectful
>like 'piss off you little bastard'.
I don't know about popping a message, but you could have fun with Slap [securitysoftware.cc]:
Note (Score:2)
Re:You said it yourself... (Score:1)
Do you even need to have that port open to the net? If it's a standalone machine with no servers, you shouldn't even be listening on that port. I remember that there was a place that described how to disable NetBios -- As I remember it, you simply attach it to some unused 'network device' that never attaches to anything... That way wintendos is happy because it thinks that netbios is still bound, but it never talks to anything outside of your machine.
Ultimately, though, I'd say (along with just about everybody else her): don't run Windows exposed to the net. I've seen emperical tests that found that you can't install and upgrade a win-2000 box while attached to the net before you get owned... One student of mine tried 4 times without getting an uninfected box.
That's the reason why everybody and their dog is selling DSL/Cable hub/firewall/routers. They're going for under $100 these days. Go out and buy one If you can't get a linux/BSD router running on an old P/66.
Happening at colleges too (Score:2, Interesting)
Re:Happening at colleges too (Score:3, Informative)
Your so-called "Senior Security Engineer" needs to get a little more training. Port 135 has absolutely nothing to do with the Windows Messenger service.
Port 135 is the RPC/DCOM portmapper in Windows. It performs the exact same service that port 111 does on a Unix box offering RPC services. It allows remote RPC calls to "find" the dynamically assigned port that their target service is running on.
Windows Messenger does not use RPC or DCOM. It uses part of the same protocol that SAMBA uses.
Re:Happening at colleges too (Score:2)
Differences betwen SAMBA RPC and DCE RPC (Score:2)
We're getting into topic creep, but I guess nobody will mind because the original topic was so silly....;-)
That is a different kind of RPC's, that pre-date Windows. It does not use 135. Microsoft usually screws things up the first time, and reinvents it several times after. This is one of them.
The RPC stuff in SAMBA dates from the old LAN Manager days, and ran over the same port the file and print sharing did (139). This stuff existed in the days of DOS and Win16, long before COM and DCOM ever existed. It worked well enough to add a few functions to this subsystem. It had lots of problems: it was not easily extensible, couldn't be run on top of other protocols, and was not object oriented, etc.
Later, when Microsoft was building what became COM and DCOM (and what was then called OLE), they realized they needed a more robust RPC mechanism. They decided to use DCE [opengroup.org] RPC [opengroup.org], theoretically an open standard. It is what DCOM is built on top of.
SAMBA continues to use the "old" RPC mechanism (for compatibility), and therefore does not use this port. If you look into the API documentation for the API's exposed on top of these RPC's, you'll see Microsoft deprecates many of them.
Re:Differences betwen SAMBA RPC and DCE RPC (Score:2)
As you're informing people about DCE here, you should also realize it was a transport independent RPC. It will run over SMB on ports 139 and 445. We implement it.....
Jeremy Allison,
Samba Team.
Re:Differences betwen SAMBA RPC and DCE RPC (Score:2)
Re:Happening at colleges too (Score:2)
DSLreports Broadband Security Forum [dslreports.com]
So the actions to take are:
Protect yourself (Score:1, Redundant)
-John
NetBSD firewall is cool :-) (Score:2)
Great product
I got one of these too (Score:1)
The fix for this should be either at the OS or user level. Personal firewalls are not hard to find, and inexpensive compared to the cost of net access. If ISP's start blocking every port that could be abused, sooner or later we'll ALL be turned into one-way consumers.
Re:I got one of these too (Score:1)
Re:I got one of these too (Score:1)
Re:I got one of these too (Score:1)
Block, but use rules. (Score:2, Interesting)
I think that what you probably want is to block the port to all IP addresses that are not in your subnet (local network). Therefore, if anyone spams you in the future, they have to be inside BellSouth, and you can (probably) get their account closed. But chances are, there's not gonna be anyone spamming like that from inside BellSouth.
That happened to me... (Score:2, Informative)
Hope this helps.
P.S. The "Messenger" service in the Services list has nothing to do with Windows/MSN Messenger, so please don't confuse the two. ^_^
Dear Slashdot, (Score:5, Funny)
When I go to work, I leave my front door unlocked and slightly ajar. The other day when I got back, I found vagrants sleeping on my sofa and defecating in my sink. Other than closing and locking my door when I leave, how can I get rid of them? Has this ever happened to you? Also, can I sue my landlord over this? Thanks.
Yours,
Confused in Cleveland
Re:Dear Slashdot, (Score:2)
Re:Dear Slashdot, (Score:1)
It is against the law for the vagrants to sleep on your sofa and defecate in your sink. You should call the police and have them arrested for trespassing.
It might be a good idea to start locking the door when you will be away, but it isn't necessary for you to lock the door to press charges against these people. Please do so, vigorously.
Re:Dear Slashdot, (Score:2)
It is within your rights to defend your property with the force of arms. If they refuse to leave, you may find it necessary to use gun control to enforce your wishes.
Gun Control - With your loaded weapon (safety off), aim at the intended target, and while slowly exhaling, squeeze the trigger.
--Mike--
Re:Dear Slashdot, (Score:2)
you're not alone... (Score:1)
Make a little firewall... (Score:4, Informative)
Re:Make a little firewall... (Score:1)
read (Score:3, Informative)
Crappy ISP! (Score:3, Interesting)
Hint: Get a linksys router and those ports will no longer be available for spam...
Hint2: Don't leave windows machine hanging on the wire like that unless they are memebers of NT domain. It will stepup the security of the Netbios connections.
Hint3: Not ever leave an improperly secured NT machine hanging on the wire like that....
Hint4: see hint 1
Re:Crappy ISP! (Score:1)
Re:Crappy ISP! (Score:1)
Re:Crappy ISP! (Score:3, Insightful)
But seriously, this NetBIOS messenger problem is quite real, and is (almost) entirely the fault of the end-user. Putting a Windows machine on the Internet without some form of firewall (software or hardware) is an invitation to get violated in some way or another. All I have to say is, these people are already once lucky - their file and print shares are exposed to the world, so with a bit of password trickery (or exposing one of the many NETBIOS vulnerabilities that exist at various patch levels of each of the Windows OS variants) one can easily access the data and/or send malicious print jobs (hint: MS Paint, black background, 100 copies. Else, SPAM)
There are also cases of people who actually run/administer a firewall that's obviously mis-configured to the point of being futile, so don't expect the mere presence of such a thing to protect you. One individual on the Security Focus Incidents mailing list is reporting this very same 'problem' on his network running Microsoft ISA firewall.
If you're unable (for whatever reason) to install a software firewall, obtain and configure an Internet router. There are dozens (hundreds) on the market, and the vast majority of them (that we've dealt with/sold) come with port forwarding to the internal machines disabled per default. For single-computer owners, SMC makes a one-port Internet router that could simply be installed inline with the users' cable/DSL 'modem' for security and peace of mind. Moreover, it saves the user from having to install annoying PPPoE client software on their machines.
Like the poster before alluded (rather amusingly) to; if you leave your door ajar, don't be surprised when you come home to find people roosting in your house, or that some of your things are missing. Sure, the person may have broken the law, but putting out the welcome mat is just asking for trouble.
Two dumb birds for the price of one.... (Score:3, Insightful)
How hard would it be to send a message back to the boxes that have some code red or similar virus. Basically you ask my web server for c:/scripts/something, you get a Windows message back informing you in no uncertain terms that your box is infected and the OS needs to be reinstalled.
This isn't an attack, but if enough people did it (just one message per infection attempt) people would soon be forced to do something because of the barrage of messages. And the people who let their boxes REMAIN infected with a virus that's been out in the wild for over a year are hardly the type of people to have locked down port 139.
Re:Two dumb birds for the price of one.... (Score:2)
Unfortunately I blew away the machine I used for that yesterday and for the life of me can't quickly Google up the app, doubtless somebody here will recognize it. It was good stuff, even reported numbers, easy to verify for security, etc.
Re:Two dumb birds for the price of one.... (Score:1)
Re:Two dumb birds for the price of one.... (Score:2)
After you're done bashing the Win2k user... (Score:1)
I received two of these messages within the last month. The first puzzled me, but only briefly, since I was ragingly drunk. The second one bothered me however. It didn't seem right to me that someone should be able to do message me like that without my explicitly allowing it (and really, how can they give you a PHD or University Degree by filling out a short 5 minute form?! It's crazy.)
In any case, my first inclination was to try and find some sort of messenging service in Win2k and turn it off, which I promptly did. But isn't this just applying a bandaid to a scratch on your arm, while your entrails are spilling out of your abdomen? I mean, this must be a sign that my system is not that secure.
But is it really true, according to one poster, that if I share a drive or a printer I have been "HACKED ALREADY"? And whether I am or not, aren't there other choices besides reformatting, changing ISPs, blocking lots of ports useful to me, or just unplugging my box? I have to say poster, that you were a little curt.
In any case, I am looking for (relative)layman's advice that isn't as drastic and cynical as this (can I find such a advice on Slashdot?) for the Win2k user; also, I would appreciate some suggestions for software a) to help clean up my system if it needs it, b) to divine the actual level of current security (or lack thereof), c)to create the firewall that so many people tell me I need. Share/freeware would also be nice on this college student's budget.
Thank you for your patience and any help is greatly appreciated.
Re:After you're done bashing the Win2k user... (Score:1)
Installing a personal firewall will likely mean facing The Wrath of the Sysadmin when he returns Monday. But looking at other posts, it seems like disabling Windows Messaging is a fairly good solution.
Frankly, I'm surprised this happened to us since our group has its own full-time Sysadmin who makes sure our little corner of the campus network is secure and up-to-date with patches, and is ruthless about security on our individual computers. As a result, most other campus Internet problems don't affect us, except when the main router goes down or a cable gets sliced or something like that. So I have trouble believing that this was caused by a lax configuration of Win2K.
FORMAT YOUR HARD DRIVE and reinstall. (Score:3, Informative)
NETBIOS CANNOT BE SECURED. If you leave your netbios ports open, you can be cracked to such a degree that it will be impossible for anyone other than a forensic analyst (who will boot from a linux or BSD boot disk) to detect. Netbios is only a viable solution on TRUSTED networks, which the Internet isn't, by definition.
YOU ARE PROBABLY OWNED. Your machine is most likely already completely compromised, and is happily working on cracking RC5 ciphers for somebody you've never met. See the honeynet project [honeynet.org] for more information (incidentally, one of the founders of honeynet reportedly got cracked by el8; everybody can make mistakes).
YOUR BEST OPTION IS TO FORMAT YOUR HARD DRIVE. The fastest, most reliable way to remove any possibility of a problem is to reload your system from a read-only media - i.e. your windows distribution disk. You must scrub the hard drive first, though; there are programs that can survive windows reinstallation unless this step is taken. You must also disconnect your Internet connection until you have a firewall running, to be absolutely safe; you should buy the firewall or get a friend with a more secure system to download one for you, since anything you download with your machine is suspect.
Hope this helped!
Re:FORMAT YOUR HARD DRIVE and reinstall. (Score:1, Funny)
HOW-TO: CYA on the Internet while using Windows (Score:2)
If you're doing things like turning on file sharing or sharing printers, it's (supposedly) very easy to hack you. I say supposedly only because I haven't actually tried this. It's such an infamous hole though that I do believe it. To turn this off, unbind the NetBIOS protocol from the modem/network card that connects you to the Internet. In Windows 2000, that you means you go to the Properties for your network connection (in the Control Panel) and uncheck the 'File and Printer Sharing for Microsoft Networks' option. (It's very easy to fix this in Win9x too using roughly the same technique.) You may have to reboot, I don't recall. That problem will then be solved.
Now to protect yourself from other intrusions and threats.
If you're just running a dial-up connection and don't leave your machine on the network for extended periods of time, then a product like ZoneAlarm (www.zonelabs.com - look for the free version) will serve you well. Actually, it serves you well in two ways: 1) it protects your machine from the outside world coming into your machine in an unauthorized fashion and 2) it protects adware on your machine from phoning home without your permission (actually it prevents everything from using the Internet until you grant permission, not just adware). This is sufficient for dialup.
For broadband users and users who want to leave their machine on the Internet for extended periods of time (more than a couple hours at a time), I recommend using an honest to goodness separate firewall. There is a lot that can be said about this, far more than I know really, but I well give you a couple pointers.
First of all, one of your options is to use a second PC as the firewall. It will need to have 2 network cards, you will need a router or hub for your home LAN, and you will have to get the cable modem (or DSL for that matter; with which I have no experience - shouldn't be too hard) working with that extra PC (via Windows would be easiest to start with). Once that's setup, go grab a Linux distribution like IPCop (or SmoothWall - they're very similar, in fact they were the same product at one time), and install it on that PC. It will require that you reformat the hard drive, so don't plan on storing any files on it. A small hard drive is sufficient. There are FAQs and forums on the IPCop and SmoothWall sites that will help get you setup.
Your second option in the category of 'real protection' (for home users anyway) is to just go buy a hardware firewall. So instead of a second PC, you just go buy a device that does essentially the same thing. I won't go into detail on these as I have no experience with them. I just thought you should know about them.
Two last points:
-PLEASE keep a current anti-virus product actively running on your machine and keep it up to date. If you need a free one, go to http://www.grisoft.com to get the free personal version of the AVG anti-virus product. This one has saved my butt several times from several infections. It may or may not be the best product out there, but it works for me.
-To protect yourself from browser window popups and other shenanigans, go grab WebWasher at http://www.webwasher.com/en/products/wwash/downlo
As always, this advice is just a starting point. Today's perfect security solution may be an open door tomorrow. It's up to you to keep yourself informed and to take action when problems arise.
Good luck and have fun!
Re:HOW-TO: CYA on the Internet while using Windows (Score:2)
Let's take a couple of examples:
1. Someone sends you an executable game via email, 'ElfBowling.exe' for example. You trust this person, so you save the file, fire up the game, and proceed to knock over some elves. The next day, you find out that everybody in your email address book received messages from you encouraging them to visit some porn sites. What happened? You ran an untrusted program. I think you'll understand this example.
2. Someone sends you their resume. You trust this person, so you save the file, and fire up MS Word to see it. The next day, you find out that everybody in your email address book received messages from you encouraging them to visit some porn sites. What happened? You didn't run an untrusted program, right? Well, no you didn't, not knowingly at least. See, Word documents can contain macros. Macros can do a number of things, like make text bold, save files, etc. Macros can also be used for bad things, like deleting all your files, for example. Again, we're back to a program that's causes the problem.
I *really* recommend that you get an anti-virus program and check out your system(s). You may have a virus and not even know it. Many viruses don't give you any visible clue that they're present until they do something obnoxious. Then it's too late. You may have to trash the entire hard drive just to clean up.
Hope that helps...
Responsibility... (Score:1)
It's an unfortunate consequence of the way the network is that one should be watching over one's own machines.
I had this happen to me, too... (Score:1)
Why not block the port ? (Score:1)
Re:Why not block the port ? (Score:2)
Disable Messenging (Score:1)
Re:Please, don't disable windows messenging (Score:1)
Is this really just now picking up? (Score:2)
Also I first just noticed it on my girlfriend's familly computer, zone alarm kept popping up, someone is trying to access net bios services. I did a tracert and it was from a NY ISP.
I wrote down the addresses of the attempted accesser (don;t want to offend any good hackers here) for later exploration (the deafault win98 install doesn't have the tools I wanted). Anyway is all this activity recently because of some as of yet undiscovered worm?, is it a worm that has been around that is starting to do this? have lots of attempted uninvited resource accessing people just decided it would be fun to try out (perhaps rotting flesh 1337 krew just posted a file or tool to do this?). Or is this something that has always happened a lot?
BTW, this was a dynamic dial-up account, not an always on DSL/cable.
Simple answer (Score:1)
Re:Thank You (Score:1)
Be Glad (Score:1)