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Microsoft Bypasses HOSTS File
whitehatlurker writes "Dave Korn announced on the Full Disclosure and Bugtraq security lists that Microsoft is bypassing local lookups for some hosts, meaning that you can't locally block some sites through your HOSTS file. All of these sites are MicroSoft controlled sites.
The general feeling in the rest of the thread is that this was to obfuscate these hosts and prevent them from being blocked by malware. However, there are no non-MicroSoft hosts listed, giving a competitive advantage for MicroSoft's anti-malware tools over other brands."
I would have thought that if you cant subvert the HOSTS file then all you have to do is to intercept any DNS lookup of these MS addresses and you would have the same effect.
If you are trying to stop MS software from talking to home, then just use an external firewall.
Michael
There is no cryptographic solution to the problem where the intended receiver and the attacker are the same entity.
It helps prevent Malware. Sure, MS might have a slim advantage, but it also prevents otherwise botted PCs from accessing MS Updates against things like Blaster. I don't see this as being such a big deal.
People should know by now, when you go MS, you don't buy the horse, you buy the farm. You wanna segment and pick and choose on the MS platform? Good luck.
Microsoft could also be using this to prevent users from blocking MSN messenger ad servers.
tom@localhost ~ $ ls -l /etc/hosts /etc/hosts
-rw-r--r-- 1 root root 519 Oct 19 12:13
....
Why can't windows just make the host files read only.
Someday, I'll have a real sig.
Why? Maybe someone will get a comment from MS.
The point is that mucking around with the inner workings of the OS is BAD, unless it is documented appropriately. Now, documentation doesn't make it good, but if they're departing from the expected behavior, they should let people know.
[Fuck Beta]
o0t!
The main problem is not that you can't block MS addresses, it is that MS is only preventing their addresses from being blocked. Since they are now getting into the security business, this gives them what could be seen as an unfair advantage.
Let us say that Joe User gets a piece of Malware, so he decides to visit a security company to find a solution to his problem. However, the malware has modified his hosts file to block security company web pages from being accessed, which is extremely typical. Joe User is not experienced enough to even know there is a hosts file that he could change back.
Joe User's first attempt would likely be to norton.com, symantec.com (both go to Symantec's main page), or mcafee.com, since these names are pretty much synonymous with antivirus software. However, all of those are blocked and he can't access them.
However, if he goes to microsoft.com, he can go there since the hosts file is subverted in the OS. Since he can't spend the time to figure out why he can't access the others, he purchases Microsoft's AV solution.
"You spoony bard!" -Tellah
Hmm. This seems a bit ass-backwards to me.
Rather than having to ignore the HOSTS file because it may be malicious, shouldn't the solution be to prevent HOSTS from getting mangled in the first place?
(oh, and on an unrelated note: why on earth is the Win32 HOSTS file buried away under C:\Windows\System32\Drivers\etc\? I mean.... 'drivers'?!!? Bizarre.
What's the frequency, Kenneth?
The only thing that troubles me is the inclusion of MSN.com in the list.
The other hosts are used in Microsoft's patch distribution network and honestly is not something the average user would ever need to block. It is, however, something a virus/spyware program would love to block. So, if you want to block those hosts, buy a firewall, they're down to about $20.
As for MSN, my only guess is that they don't want to block updates for MSN messenger.
What we have to remember is that these sites are required to fix a broken system, so I don't view this as just an advantage for MS antispyware.
An automatic update of WMP and your PC gets owned, and nothing can be done to prevent it!
Because using an IP address for the program to access causes problems if your server's IP changes. Simple as that.
...if Microsoft had documented this behavior. Yet still, I fail to see what the big deal is. So you can't force an IP address to a domain with hosts.txt for some sites that microsoft controls. If you need to do that, for example for some corporate filter or updating solution, you could just modify your own dns server. Home users on the other hand get more reliable access to windows update, which is very important. Otherwise it would be trivial for malware to block the computer from recieving updates, and the automatic updates would silently fail.
Cheers, Fogger
Um... I didn't do it!
If the adware can change your hosts file then this is pretty useless anyway. Now all the software has to do is run a script that does the following
nslookup whatever.microsofts.domains
takes the list of return addresses and
route ADD destination MASK mask INVALID INVALID INVALID foreach
and your traffic to MS wont even leave the network card.
Now I'll have to include a disclaimer...
Just another reason to continue using a more robust system :)
"The likes of Facebook and WhatsApp are free to those whose privacy is of zero value."
Who cares?
Nothing prevents you from not using the operating system's resolver. Its trivial to implement your OWN DNS client in your programs, bypassing any HOSTS settings and other DNS resolver issues.
I've never seen so many people who were so clueless and misinformed about the technical issues involved here.
I'm wondering if the behaviour will change if you just go into "services" and disable the DNS client.
I recommend this anyway. In theory it will increase the number of requests your machine does. But in practice it has saved me a lot of "try rebooting" calls.
Anyone out there with XP who can reproduce this?
A court of law has determined that Microsoft is a monopoly. One of the anti-trust regulations specifies that you cannot use your monopoly power to force your way into another market; that was the heart of the conviction against Microsoft in the Netscape case. Microsoft used their monopoly to oust Netscape as the dominant browser by bundling, which is illegal.
Now they are using that same monopoly power to take over the anti-malware market.
I'm rather ambivilent about this. On one hand, it is just one more case of Microsoft waiting for a market to mature, then forcing their way into it. On the other hand, this market wouldn't exist if it wasn't for their own shoddy products, so it's really Microsoft's reponsibility to fix it. However, malware protection software isn't the correct answer, it's just the most expedient, with a potential for additional profit.
All-in-all, it's just Microsoft's usual game: own the system, rig the system, use that to take over another system. Keep secrets, and act all coy when your secrets are discovered.
Microsoft is to software what Budweiser is to beer.
The real problem with this is that: 1. It wasn't documented, so people had to discover this non-intuitive exception. 2. It defeats the purpose of the hosts file. Had they also included the other AV vendors in the list and made the function public it may have seemed like a practical band aid to the hosts file hijacking problem. Instead they made it M$ only and hid it so it looks slimy. The issue is being addressed is also PEBKAC related.. If Windows users weren't logged in as admin the hosts file would be off limits.
"Safeguarding" your hosts file against tampering is pointless. Yes, a few trojans toy with it. The ONLY place that's ever redirected afaik is updates.microsoft.com.
So this is going to be celebrated as the hack against malware that keeps you from updating. Ohhhh great. Ok, next move from the malware writers is simply to keep a thread running that checks if something is coming in from the "unwanted" sites. If so, it's deleted before execution. Problem solved.
There is no techical solution for social problems.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
Maby because it's not illegal?
If you want to bypass the hosts file all you need to do is connect by using the IP address as opposed to the DNS name. Sure it seems a bit more complicated or problematic (incase DNS->IP pointing changes) but Im sure all malware programs would rather specify an IP instead of DNS. I would if I was creating a malware program :-)
(And my troll is in Haiku)
Windows xp still better
need to run useful software
Mac and Linux are toys
that is not quite right
both the troll and the haiku
are somewhat lacking
but please understand
Mac and Linux are not toys
just other systems
Windows has problems
while it does have more software
it is insecure
please try something else
you might find that you like it
don't stagnate yourself
if end users switch
developers will follow
more software for all
so please help yourself
and help the rest of the world
try something else
if you don't like them
that is your prerogative
simply don't use them
but I'm warning you
going back is much harder
but it is your choice
other OSes
few viruses and malware
true computing bliss
as for poetry
haiku sylable count is
5-7-5
IIRC, it's a hangover from Windows 3.1 or maybe Win95.
-- You are in a maze of little, twisty passages, all different... --
-Considering the most popular non-microsoft patches are to tcpip.sys and uxtheme.dll
Here's a threaded view of the Full Disclosure thread, rather than the first follow-up post to Dave Korn's OP, which the story submitter seems to have decided would be a better way... http://archives.neohapsis.com/archives/fulldisclos ure/2006-04/thread.html#268
"None are more hopelessly enslaved than those who falsely believe they are free." -- Goethe
If only most applications could run properly with user-level permissions.
I admin a tiny number of desktops and not one of them worked with user-level permissions.
-Mysterious errors
-Application functions that simply did not work.
These are *very* generic XPSP2/Win2k desktops with Office 2K/2003.
Initially, I was not deterred. With every hurdle crossed with ugly hacks, there was yet another error with no documented solution.
Someone posted a link to NIST(?) documentation that I eventually used. It's by far the best way to do a job that the OS was never designed to perform.
Mod parent way down
http://www.maxineudall.com/2010/02/should-economists-be-sued-for-malpractice.html
Upon further thinking, this whole article is flawed and perverted.
"Microsoft is bypassing local lookups for some hosts, meaning that you can't locally block some sites through your HOSTS file."
I already said why that's stupid anyway.
"All of these sites are MicroSoft controlled sites. The general feeling in the rest of the thread is that this was to obfuscate these hosts and prevent them from being blocked by malware."
Well, malware authors are just going to replace the resolver function instead of aiming for the easier target. If they can replace entries in the hosts file, they have sufficient privileges anyway.
"However, there are no non-MicroSoft hosts listed, giving a competitive advantage for MicroSoft's anti-malware tools over other brands."
That's really far-fetched. Let me see: Most users use their Windows as root-equivalent because of sucky software and because they don't know any better. Spyware can replace the hosts file to block access to Microsoft's auto-update because users are root. So instead of fixing the fundamental problem, Microsoft does what it does best: kludges, bandaids, bullshit. And now suddenly this is viewed as a "competitive advantage"?! Remember people: don't attribute to malice what can be explained with stupidity.
To me this is only proof again that anything related to Windows is a swamp of bad design, ugly hacks and inconsistencies. I wouldn't construct an evil intent on Microsoft's side here. It's just their usual incompetence.
Of course it runs NetBSD. BTC: 1NT7QvbetmANwaMzhpVL6
What it means is that if a rootkit alters the internal IP tables for a Microsoft address, most virus checkers won't pick up on it (the Hosts file will be untouched) and it will be impossible for the user to override the problem in order to get to Microsoft's website to download the necessary patches.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Just look Here for more info:
= /library/en-us/dns/dns/dnsquery.asp
a ys=9999~start=20#15902844
http://msdn.microsoft.com/library/default.asp?url
Also you can defeat a Host file by simply changing the priority of lookups using the registry, more here:
http://www.dslreports.com/forum/remark,15900699~d
Black Gray White Hats Unite to protect http://testing.OnlyTheRightAnswers.com
Here' a simple solution to the Microsoft controlled DNS HOSTS file:
http://treewalkdns.com/
Allows you to bypass Windows' own DNS server and gives you the useful feature of making DNS queries much quicker than resolving to your ISP all the time, among other benefits.
Very easy to install for Joe User and just as easy to uninstall.
HTH
Visceral Psyche Films