Most Home Routers Vulnerable to Flash UPnP Attack

An Anonymous reader noted that some folks at GNU Citizen have been researching UPNP Vulnerabilities in home routers, and have produced a flash swf file capable of opening open ports into your network simply by visiting an unfortunate URL. Looks like Firefox & Safari users are safe for now.

Nothing new, really

It all hinges on going to a malicious web site. Just like email trojans, if you resist temptaion and use some common sense, do you really have to worry about this?

Re:Nothing new, really

Yes. You may not be sure if a site is malicious or not, without visiting it.
And some sites may become malicious suddenly because of all those syndicated ads around.

Re:Nothing new, really

Yup, I have seen people computers infected from msn.com the banner ad's were at one time installing spyware from the default IE home page.

All it takes is to get your nastyness in a bunch of Ad rotations from doubleclick and other scumbag webad companies and you can hose a huge swath of the net.

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Firefox with AdBlock+, EasyElement, EasyList, SpyBot S&D, SpywareBlaster, disable Flash and UPnP, SMC Barricade 7004VBR (w NAT and firewall)...what's the problem? I've been running this for several years with no infections.
99.9% of the shiit that get

Re:Nothing new, really

I use Linux with Seamonkey and..... uuhhh nothing else.
No infections either. :)

It looks like your doing everything except the simplest solution.

Oh and yes I use UPNP.

Re:Nothing new, really

Firefox with AdBlock+, EasyElement, EasyList, SpyBot S&D, SpywareBlaster, disable Flash and UPnP, SMC Barricade 7004VBR (w NAT and firewall)...what's the problem?

That none of this is default?

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Yup, I have seen people computers infected from msn.com

Isn't that redundant? The GP already stated,

It all hinges on going to a malicious web site.

Re:

That is the problem. It seems as though Flash is the way to go on this and if you're running Firefox you just run the Flashblock add-on. It puts a little 'f' where the flash module wants to run. Between Flashblock and AdBlock I love the web.

Re:Nothing new, really

Well yes. If you never visit a site with adverts. Or the Internet as it's otherwise known. Sure, you can block them (and I do) but sometimes sites switch to new providers and you are vulnerable for the time it takes to update the block file.

I'm not really surprised to be honest - I always thought UPnP looked fishy to me so I disabled it on my router. I don't like the idea that anyone coming to visit can plug in their malware-ridden Windows laptop and reconfigure my router. Sure, having it turned off means X-Box Live is less happy but that only decreases the number of people who can call me "fag" on a daily basis. I wonder if Microsoft will update the X-Box Live support page where they say that UPnP doesn't make your network insecure...

I also have Flash disabled by default because it is well known to be insecure and buggy and a delivery system for malware. Most proper web-browsers either let you enable flash on a per-site basis or will allow you to do so with a plug-in and this is really the way to go.

Re:Nothing new, really

The annoying thing about it is that applications (especially games!) are written these days assuming you're either directly connected or behind a uPNP router. I had a hell of a time trying to get C&C3 working over my BSD based router because it assumed I was using uPNP.

Re:Nothing new, really

Yes, but the social engineering requirement is more or less gone in this case. It takes substantially less work to convince someone to click a link than to download a file. (Granted, Bonzai Buddy got people by just being a purple ape.)
Why, look no further than the MyMiniCity/Goatse/2girls1cup links being posted here in every thread! At least one person clicks and ends up warning others. (Either by downmodding or posting.) Why, you just need someone who's curious enough to click.

On the other hand, it requires a bit of work to get someone familiar with malware to click on a 'you just won' banner and download the mystery prize. Don't even get me started on random email attachments following nonsense messages.

Turn off UPNP

I thought the recommended steps for setting up a router were:

A. Unbox
B. Throw away the disk
C. Plug in your machine, Turn on the router and navigate to the webgui
D. Turn off UPNP
E. ??? (Change default name and password, set WPA, Turn off SSID etc....)
F. Profit...

The point is, I'd always been told to turn off UPNP 'cos sooner or later something is going to open ports that you don't know about.

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Change default name and password, set WPA, Turn off SSID etc....

I'm okay with all of that. The only thing I never get is why to turn off the SSID broadcast. If it's well secured, it doesn't matter if they know it's there or not. Besides, I'm pretty sur

Re:

Right. And it's also rather annoying when you do a quick look around to find a vacant channel. "Oh look, no one is on channel 1, lets use that!" Only to find out a short while later that 5 networks are using that channel, but all of them have SSID broadcas

Re:Turn off UPNP

Simple. Buy one of the new Linksys Draft-N routers and put it in 40MHz mode. It'll stomp all over them.

Re:

Er, you 'don't get' the whole 'change default password crap'? Even though you 'usually' look up the password on a 'list of manufacturer default'?

Want to run that by us again? :-)

Re:Turn off UPNP

The other funny thing is that he claims to be "completely crashing a router so it resets to factory defaults". Now most of them, do that after a firmware update (but you have to already have admin access for that, so no glory there), or if you do a a hardware reset, in which case you no physical access to the device. I have NEVER heard of any router that will reboot with factory default settings if it crashes (and believe me, my first D-Link router several years ago crashed on a near daily basis - the poor little processor inside of it couldn't keep up with the number of connections my P2P software was making).

WHERE $money; PUT $mouth

I dont get the whole turn off ssid and mac filtering, change default password crap. more often than not kismet works out the ssid if hidden, mac can be spoofed using macchanger, and i usually guess peoples passwords or look it up on list of manufacturer default list. the alternative is to completely crash a router as it just resets with factory defaults and you can completely take over the router.

I live in Cincinnati, Ohio. You come (wirelessly) break into my router, change the current settings by opening port 1337, and I'll refund the cost of your travel (as determined by hotwire or expedia's fare rates on the day of your travel), and pay you $100 additional, all in cash on the same day.

It's a SOHO router, but I won't tell you what make/model -- if your prowess is as you claim, you should have no trouble determining that. You may not enter the apartment or inspect any systems currently connected -- but you shouldn't need to. I have no other firewalls, proxy servers, or tricks on the front end of this router -- it's straight from modem to unit. You may have 48 consecutive hours to complete the task.

Still confident? Email me at radams theatsign tohuw.net and make arrangements.

Re:WHERE $money; PUT $mouth

Challenging an anon coward...

Yeah, that'll work.

Re:WHERE $money; PUT $mouth

I'm aware of both of those issues. My offer still stands.

Re:Turn off UPNP

There are a couple of principles you seem to be missing, starting with the idea of relative security. It is possible to make a wireless network 'more secure' than it is, as configured by default out of the box. It does help, in the same way that improving the security on the average home helps. Will it stop someone determined to get in? Very probably not. Can you make it easier for someone to go to the house next door, that has not implemented any of the steps to secure themselves? Yes. As a rule, people are usually lazier than they are determined to get into one specific network. If folks are serious about wanting a secure network, there are all sorts of things they can do. Most of them involve not having a wireless connection, or spending a *lot* more time, money, and effort on it than folks do on the average home network. Having noted that, let's look at your list.

Hidden SSID: One commonly expressed theory behind hiding a SSID is similar to why you lock your car. If your car is locked, it's a less attractive target than one which isn't. Hiding your SSID does make a network a less obvious target than one which is visible. It doesn't impede any serious search for networks by someone knowledgeable, but it will remain hidden to casual view. Is this vaguely inconvenient? Possibly, but then, really, so are locks. Really, I've never been so fond of that analogy.

If you like, I think a better analogy might actually be that hiding your SSID is like planting a bush in your front yard that obscures a direct view of your front door. It doesn't really make your door any more secure, in and of itself, but it might make it less obvious that there's a door there to begin with. Someone simply walking by might not notice it, but someone sitting in their car, watching folks come and go is sure to notice it. It just makes it more likely that a casual passerby might try one of the obvious doors nearby to see if they can get in, rather than trying yours.

MAC Filtering: Similarly, MAC filtering is better than not MAC filtering. The observer can't get on the network unless they spend enough time analyzing active traffic to sift for MAC info. Yes, with the right tools 'enough time' is relative, and not all that long. But, if you're not around using your wireless network when they're doing the analysis, it's difficult to obtain that info, since your MAC isn't being broadcast to begin with. Is it perfect security? Not by any means, but, again, it's a lot easier to get onto a network that's not using it than one which is. Not everyone is running Kismet with a wireless network card configured in promiscuous mode, and even with the number of folks who are, most are more likely to roll a half block down to the completely open network that's almost invariably there than spend time trying to get onto the more secure network, simply for the challenge of it.

Change the default password: If you seriously don't understand this, then you are completely clueless, regardless what tools you're using. Just because you can guess a few passwords using the short list that unimaginative folks commonly use doesn't mean that you can guess any password. (Of course, script kiddies commonly don't have any idea why what they use works, but that doesn't mean it doesn't.) If you were thinking at all about what you were writing, you'd see you make the point yourself as to exactly why it's important. You commonly 'just look up manufacturers default passwords'. If they set a proper password, it makes things more difficult, and you have to try to guess it. With a good password, you're not going to simply guess it.

Crashing the Router: As for your alternative, no decent router should ever come back up with the factory presets after a simple crash. It should always come up with the custom settings, or, failing that, remain hung until manually reset by hand. Even if they do come up with the factory defaults, for modern routers at least, that should be with the external management interface disabled.

Note that the above sentences use a very important word -- 'should'. If they do, then they pretty much fall outside of the category of 'decent', and fall straight into 'crappy'. I can only hope this also doesn't translate into 'ubiquitous'. Of course, if it did, then folks wouldn't spend time writing tools to try to get around all of the above, they'd just immediately try to 'crash' them, without bothering with any of the other steps. Note I'm not saying that trying to crash the router may not sometimes be effective, just that it should hopefully not be very large to begin with, and should over time be dwindling. But, then, there's that 'should' again...

For the same reasons, firewalls should always fail to a 'safe' configuration (stopping all traffic) in preference to failing 'open' (allowing traffic). Better to require manual intervention to resolve a problem than to expose network/data.

Hopefully, this has answered at least a couple of folks questions about why these various options are available, and why they should generally be used. All things being equal, if everyone used all of them, they probably wouldn't be too effective for anyone (other than changing the default passwords. That's always important.), because all implementations would be equally difficult to attempt to break onto. But, as long as there are differing levels of adoption, some networks will be easier to get onto than others, and thus become those more likely to be compromised.

Does that mean that networks that implement all of them will be secure? No. But, they'll be more secure than those that don't implement them.

Oh, and yes. Turning OFF uPnP is VERY important, too. From a security perspective, it's awful. Let local software mess with router settings whenever it wants? Terrible idea. The whole basis for it is the idea that the end user doesn't know enough about security to be making changes to the configuration to begin with, so software should be able to reconfigure security settings on it's own, without user intervention. That's asking the fox to guard the hens...

Anyway.

We now return you to your own regularly scheduled rant.

Re:

planting a bush in your front yard that obscures a direct view of your front door

From a security perspective, I would never want one of these as, if someone were at my front door trying to pick the lock, they would be obscured from view. I find living in a neighbourhood where there is the appearance that all the neighbours are nos

Re:

Why don't you use WPA? It's 1000x better than WEP.

I have a crusty old PDA which knows nothing about WPA.

The asshole that wants to crack it will need much more time, and as such will be discouraged even more

There are open default and linksys APs right next to mine. Why bother with mine?

Re:Turn off UPNP

I thought the recommended steps for setting up a router were:
... D. Turn off UPNP

I guess that is the wise choice. But UPnP is very handy for me because my home machines always get different IPs from my router, so if I want to port-forward BitTorrent ports to me laptop, desktop, etc., I have to go in and change the port-forwarding config on the router every time I get assigned a new IP. Big PITA. But then I discovered how Azureus can use UPnP to automagically forward the ports for me on the fly. It seems to work fine. Too bad it's a security risk.

Re:Turn off UPNP

See if your router supports port triggering [wikipedia.org] or look for that feature in your next router. It is a way to automate port forwarding, and would help you in your setup without being the security risk UPnP is.

Re:Turn off UPNP

Configure your DHCP server (your router in this case) to always give the same IP to the machines that you run server software on. It's trivial, really.

Re:

WRT54G (Arguably the most prolific consumer grade router in existence) does support static IP assignments via DHCP.

Certain versions, at least, do not. That was the main reason I switched to DD-WRT. The compact version also did not support it last I knew (a friend has this router).

But yes, even the D-Link DI-704 that I purchased in 2000 for $20 (i.e. it was really

Re:Turn off UPNP

All of us self-respecting geeks realized, years ago, that it was far cheaper, easier, and better to run OpenWRT/DD-WRT/Alchemy on a WRT54G from Wal-Mart, than to maintain yet-another-fucking-PC at home.

It's a good gig: A Linux box with 5 Ethernet ports and a WiFi radio for ~$50.

Having zero moving parts and negligible power consumption is a big help, too.

Re:

You preach to the choir.

I have several PCs (one desktop, one old laptop, one ancient laptop) which I've tried to eliminate moving parts from.

The desktop is a machine which I occasionally use through a KVM, which only exists to operate a Soundblaster Live c

Re:Turn off UPNP

BitTorrent users often use uPNP to punch a hole through the router for torrents. Many torrenting "how-tos" specify using uPNP for this purpose, and it's commonly enabled in many BT clients like Azureus and uTorrent. For most of these people, uPNP is a godsend since it eliminates the need to mess around with portforwarding in the router configuration.

Re:Turn off UPNP

For most of these people, uPNP is a godsend since it eliminates the need to mess around with portforwarding in the router configuration.

If uPNP is a godsend to those people... they need to get a better God.

Re:

Agreed. I'm sure there are even games that support uPnP so when you host a game, the appropriate port is automatically forwarded. IMO, if you keep a tidy computer network with virus scanners on your computers and scan for malware, then it's not much of an

Open WiFi + this = trouble?

This will take an old-new argument to "to free or not to free my wifi" questions.

Re:

Open WiFi access points are a security nightmare regardless of exploits like this, so the same basic advice still holds: open WiFi access points should be isolated from your "trusted" network. Security vulnerabilities aside, open access points are a legal

Re:

From the article's comments:

The portforwarding rule attack was given as an example as this is probably one of the things that cannot be used right away by script kiddies and it is sufficient enough to prove a point.

The fact that ports can be forwarded to a

Mozillazine forums had this two years ago

There was a thread on the Mozillazine forums [mozillazine.org] about malicious JavaScript changing router settings about two years ago. Unfortunately, in October Mozillazine had a big foulup and many threads (and users, me included) were lost [mozillazine.org]. I cannot find the thread now, but if I do I'll post back with a[n] URL. The thread's conclusion was that one should never leave the default password on the router.

My Home router is a Linux NAT Box.

My home router is a Linux NAT Server. (I sorta have a pissant about the fact that those things to be called "Routers" I have a DI-704, and I couldn't get it to route between two actual subnets. It only would NAT.

Anyway, my point. What about things like the Linksys WRT54GL?

The thing is, it would be awesome if there was a flash drive driven Linux device with a Cisco Style com port that ran off flash, could be OpenLDAP Server, Samba DC, Kerberos KDC, NAT Server, or actual router WITH a Cisco style Console port that are cheap. Why does this not exist??

Your point ?

Your point seems to be a question.

Anyhoo, there's nothing uber special about Flash, you can just put a CF/SD card in an IDE/SATA adapter and attach it to a suitable computer, such as one of the fanless EPIAs [mini-itx.com], that one even has dual gige.

Re:

If you really want to tinker around with Linux as a home NAT/Firewall device, you would love the Soekris [soekris.com] NET4801 [soekris.com] or NET5501 [soekris.com] boxes.

I have one (I have no financial relationship with them other than customer) and I really love it. Very low power, 4GB flash c

Let me be the first...

...in this thread anyway, to recommend the flashblock plugin [mozdev.org].

I installed it a couple of weeks ago, and really enjoy it. Banner ads have all but disappeared, and I don't even really notice (except for faster page loads and cleaner page layouts). If I want

Re:

Great idea because IE runs Firefox plugins SO well.

Firefox isn't vulnerable to this in the first place, so your advice means nothing here.

Browsers

as usual opera is resistant.

Open open...

[...] a flash swf file capable of opening open ports into your network [...]

Hold on, now I'm confused: does this attack open open ports, or does it open ports open? Or even worse, does it open open open ports? :D

Don't try this at home

I've always wondered about using StumbleUpon as a distribution method. I wonder if it is possible in such an exploit somehow force your profile to Thumbs Up the infected page, making it spread at a maximum exponential rate, since the rating system would on

What about the Wii browser

It's Opera browser that Runs an OLD version of flash on a Wireless network. I mean, do we need to worry about this when we go to the wrong site from our Nintendo? I hear they update it from the connect24 but not that often...

Turn off UPnP!

Turn off UPnP! Why on Earth do you want it on anyway? That's the problem here - an XSS is one matter, although being able to send SOAP-style requests across your local network is a major concern. But having a router that automatically opens ports based on virtually zero authentication? A nightmare waiting to happen.

Never used it. Never wanted it. Never turned it on. Always turned it off on EVERYTHING. UPnP is the problem here - a simple (unauthenticated) HTTP-style page requested in a browser suddenly starts opening ports to your network. It should not happen. Even my DSL router/wireless router/Linux router has SSL only, passworded access to do anything even approaching opening ports. And if a webpage pops up with an authentication dialog with the header "Wireless Router" and you type in your password, then you're a fool, unless you specifically requested the router's configuration page.

There's rarely even a log of what UPnP has done - which ports it's opened in the past etc. for whom.

Just turn the damn thing off. It's too dangerous.

Re:Turn off UPnP!

The thing is, it's just so damn useful. For a TCP/IP savvy person, setting up, say, a Bittorrent client, or Xbox Live online play without UPnP is a chore. For normal people, it's voodoo. With UPnP (and the right client) it Just Works. Convenient or secure... guess what most people will choose?

But, agreed, it's scary stuff, if you believe your router ought to be a firewall. What's really needed is for home routers to start implementing authenticated UPnP, and for clients to work with it. (I must admit I've only glanced at the UPnP specs, but I seem to recall seeing references to an authenticated flavour).

Re:

That depends. Did you install UPnP [dd-wrt.com], presumably because you want random ports to open up on your DD-WRT router without your consent?

If not then you're probably quite safe from UPnP based attacks.

Re:DD-WRT?

If the firmware has UPnP IGD enabled, then your machine is vulnerable to this attack.

The vulnerability is really Flash not restricting what untrusted scripts can do. The router's UPnP IGD profile is working as designed - an application on a machine within the firewall requests that an incoming port be forwarded, so the router does that. This is useful for VoIP, IM, P2P and other applications that need to be contactable from the outside world. Malicious programs that are running on your machine can always initiate outgoing connections, so generally the UPnP IGD is not allowing anything that cannot already be done. In the case of Flash, it is probably blocking most outgoing connections, so UPnP does expand the possibilities for a malicious Flash app to initiate connections with your machine. But unless Flash also allows you to open server sockets, the attacker would also need to find an exploitable service running on your machine.

All this should be detectable by a decent firewall program running on your local machine.

Re:Questions about Wireless Router Security

If a flash plugin can make outgoing XML requests it can persuade a upnp server to make your machine wide open, thus completely disabling your firewall. Making those kind of requests sounds like the kind of thing you want Flash to do, so I'd imagine all versions are vulnerable.

There are some ports.. 137,139,445,etc. that you really don't want on the open internet. If the plugin does something like a port forward of 0-65535 to your machine suddenly *every* service on there is wide open to any attack. It'll bypass protections from eg. the default XP firewall as the packets will appear to be coming from the local LAN (the router) rather than the original source.

It's not just flash (although a malicious advert on a page is the most obvious vector for this). Anything that runs on your machine can do it.. I reckon you could craft such an attack in javascript even (XMLHttpRequest with the right code).

Once the ports are open anything that manages to run on your machine can leave itself wide open without having to make telltale outgoing port connections (although it's often said that outgoing connections are the reason upnp is 'not worse' than existing protections, no working trojan would work in that manner, since the target of the outgoing connection would quickly be found and shut down.. OTOH leaving a trojan on your machine listening on your machine waiting for the command to send spam/infect others/distribute child porn/whatever is much more real a thread).