Black hats attack gaping DNS hole Miscreants are actively exploiting a gaping hole in the internet's address lookup system that can cause millions of web surfers to receive counterfeit pages when they try to access online banking services and other types of websites. The first confirmed instance came on Tuesday, when security researcher H D Moore discovered a …
1. 212.104.130.65 (resolver2.th.eclipse.net.uk) appears to have GREAT source port randomness and GREAT transaction ID randomness.
2. 212.104.128.102 (uplink2-bba1.th.eclipse.net.uk) appears to have GREAT source port randomness and GREAT transaction ID randomness.
Test time: 2008-07-31 18:36:45 UTC
ISP - Verizon (buncha scumbagz)
DNS resolvers - 71.242.0.39, 71.242.0.36
Doxpara and DNS-OARC basically agree that my ISP's DNS servers are okay, but my local NAT router isn't randomizing the source ports very well.
My router is a re-imaged Linksys - guess I better get around to updating it :-(
(Icon? "Proceed with this nonsense at flank speed!")
Came back as safe from doxpara.
dns-oarc gave the following :
1. 194.168.8.110 (winn-dnsbep-2.server.virginmedia.net) appears to have POOR source port randomness and GREAT transaction ID randomness.
2. 194.168.8.109 (winn-dnsbep-1.server.virginmedia.net) appears to have POOR source port randomness and GREAT transaction ID randomness.
3. 62.254.32.148 (belf-dnsany-1.server.virginmedia.net) appears to have POOR source port randomness and GREAT transaction ID randomness.
Pretty middle of the road then.
DNS Resolver(s) Tested:
1. 194.74.65.68 (ns6.bt.net) appears to have POOR source port randomness and GREAT transaction ID randomness.
2. 194.72.9.34 (bcn.customer.bt.net) appears to have POOR source port randomness and GREAT transaction ID randomness.
Test time: 2008-07-31 18:49:17 UTC
https://www.dns-oarc.net/oarc/services/dnsentropy
DNS Resolver(s) Tested:
68.87.72.131 (chic-cns01.area4.il.chicago.comcast.net) appears to have POOR source port randomness and GREAT transaction ID randomness.
68.87.77.131 (detr-cns01.westlandrdc.mi.michigan.comcast.net) appears to have
POOR source port randomness and GREAT transaction ID randomness.
68.87.72.133 (chic-cns03.area4.il.chicago.comcast.net) appears to have POOR source port randomness and GREAT transaction ID randomness.
Test time: 2008-07-31 18:37:53 UTC
---
When I changed my DNS forwarder to one I knew was patched, it reported GREAT GREAT.
---
DOXPARA said that things were good, and only reported ONE of the DNS servers I forward to.
DNS gets attacked all the time, maybe someone else just spilled their version.
He should have created a encrypted file with the details and publicly posted it.
So who knows.
Thing is people will use the known exploits just as they emerge, the chaos helps to cover tracks. I still think what he has done is a bit irresponsible, DNSSEC has been preventing these attacks for a while, and the latest bind patch was available before this went public. So, what we have here is a known attack given a lot of publicity.
Well, if the sec guys can keep up with the numbers, they may find quite a few of the crackers, but this has upped the volume.
DNS Resolver(s) Tested:
68.238.112.36 appears to have POOR source port randomness and GREAT transaction ID randomness.
68.238.96.38 appears to have POOR source port randomness and GREAT transaction ID randomness.
68.238.96.37 appears to have POOR source port randomness and GREAT transaction ID randomness.
Ok, does this mean that redirection to a bogus site would still work?
1. 205.152.132.31 appears to have GREAT source port randomness and GREAT transaction ID randomness.
2. 205.152.144.13 (oldmail1.mia.bellsouth.net) appears to have GREAT source port randomness and GREAT transaction ID randomness.
3. 209.244.5.159 (ics2.Atlanta1.Level3.net) appears to have GOOD source port randomness and GREAT transaction ID randomness.
1. 195.8.69.7 (resolver1.uk.clara.net) appears to have GOOD source port randomness and GREAT transaction ID randomness.
2. 80.168.69.20 (resolver3.clara.net) appears to have GREAT source port randomness and GREAT transaction ID randomness.
I like my ISP, not cheap, not throttled either. No apparent port blocking. Local call rate support. Just in case anyone wants to jump ship from any Phormised ISP.
No I am not a Clara employee ;-)
1. 90.207.242.85 (5acff255.bb.sky.com) appears to have GREAT source port randomness and GREAT transaction ID randomness.
2. 90.207.242.82 (5acff252.bb.sky.com) appears to have GREAT source port randomness and GREAT transaction ID randomness.
3. 90.207.242.87 (5acff257.bb.sky.com) appears to have GREAT source port randomness and GREAT transaction ID randomness.
Yes, they're vulnerable. The transaction ID is irrelevant as it is guessed by the attacker with chances of a hit being one in 65536 per shot. The crux of the matter is a static upstream query port on the recursive server being queried, allowing the attacker to both send unique unresolvable queries within the target domain (1.example.com, 2.example.com...) to port 53 AND know which port the server is listening for an answer on. He then fires answers at it pretending to be the server the resolver is querying (remember, this is UDP. No state, easy to spoof, no reply needed once you get an answer accepted). You only need to guess the transaction ID correctly once and then you've polluted the cache for the entire example.com domain for however long you set that answer's TTL to (or the cache lifetime, whichever is smaller) by dint of in-bailiwick answers always being accepted for the whole domain. All the real example.com DNS servers will send back is NXDOMAIN, which doesn't get cached so you have, in effect, limitless query headroom to get the transaction ID correct without the risk of the real servers populating the cache first.
What the patch does is enable the server to use a random source port for every query in a recursive search, spoiling the cracker's ability to track which port the server expects a response on, thus giving the cracker no opportunity to insert his own bogus answers. It is, unfortunately, security by obscurity. We need signed roots and DNSSec. DNS is and always has been insecure. It's only a matter of time before more holes are found and this whole song and dance commences yet again. Of course, that implies ISPs will care enough to set up trust anchors, but that's a discussion for another day.
By the way, if anyone thinks adding 1 IN A x.x.x.x, 2 IN A x.x.x.x etc. to their zones is a defence, just ponder the use of very small shell scripts, uuidgen and sed to create the hostnames to query. I'm sure you'll agree that this idea is no defence at all. The hostname used is just a simple way of explaining the exploit. Even your run-of-the-mill skiddie isn't going to be that obliging. Patch. Now.
After a whole 3 seconds of Googling, I found this page on the Gentoo site:
http://www.gentoo.org/security/en/glsa/glsa-200807-08.xml
'All BIND users should upgrade to the latest version:
Code Listing 3.1: Resolution
# emerge --sync
# emerge --ask --oneshot --verbose ">=net-dns/bind-9.4.2_p1"
Note: In order to utilize the query port randomization to mitigate the weakness, you need to make sure that your network setup allows the DNS server to use random source ports for query and that you have not set a fixed query port via the "query-source port" directive in the BIND configuration.'
So did you check your "query-source port" directive in BIND?
141.154.0.68 (gtebo.ba-dsg.net)
141.155.0.68 (gteny.ba-dsg.net)
151.197.0.39 (home4.bellatlantic.net)
151.198.0.39 (home5.bellatlantic.net)
151.201.0.39 (home6.bellatlantic.net)
151.202.0.85 (nyc2-qwest.bellatlantic.net)
151.203.0.85 (boston2-qwest.bellatlantic.net)
All come up with poor source port randomness, great transaction ID randomness.
1. 64.187.29.134 (h64-187-29-134.gtcust.grouptelecom.net) appears to have GREAT source port randomness and GREAT transaction ID randomness.
2. 64.59.135.133 (nsc1.so.cg.shawcable.net) appears to have GREAT source port randomness and GREAT transaction ID randomness.
3. 64.59.135.135 (nsc2.so.cg.shawcable.net) appears to have GREAT source port randomness and GREAT transaction ID randomness.
Re: Verizon
Thanks for the explaination about port versus transaction randomness.
The thing about all this that really boils my bottom is that even though I have bothered with a home router, firewall, anti-virus and such for years my IS-freaking-P's unpatched DNS could render such preparations moot.
Alas, poor internet, I knew it Horatio. A place of infinite wit and zest.<holding 4-port router, talking to it>
DIG: "62.6.40.162 [indnsc70.ukcore.bt.net.] is POOR: 26 queries in 3.8 seconds from 25 ports with std dev 271"
WEB Version: POOR source port randomness GREAT transaction ID randomness.
I get the POOR source port warning whatever test I use. I run my own LAN and LAMP setup via my otherwise vanilla BT Broadband connection (via HomeHub).
I suspect other factors rather than BT's DNS may be involved in the results - it would be great if someone could give us a clue and briefly explain what may restrict source port randomness. I have a clue (NAT/Firewall etc) but some folk out there actually 'know' :-)
OR - should I rely on the test and BT *are* actually POOR/GREAT rated!
Using my usual local dialup number:
Your name server, at 209.179.23.207, appears to be safe, but make sure the ports listed below aren't following an obvious pattern (:1001, :1002, :1003, or :30000, :30020, :30100...).
@ Steve Evans
I don't know how to check the ports either.
68.28.250.92 (ns2.atlngar03.spcsdns.net) appears to have GREAT source port randomness and GREAT transaction ID randomness.
68.28.242.91 (ns1.atlngar03.spcsdns.net) appears to have GREAT source port randomness and GREAT transaction ID randomness.
Test time: 2008-08-01 07:24:35 UTC
For my wireless broadband, Sprint fixed it within the last week.
For my Verizon woes, I have pointed my router to OpenDNS, as opposed to letting my ISP do my DNS and that works just fine.
Thanks again to Chronos, et al, for the information. Yet another reason to love El Reg.
This post has been deleted by its author
"Your ISP's name server, 80.3.128.148, has other protections above and beyond port randomization against the recently discovered DNS flaws. There is no reason to be concerned about the results seen below.Requests seen for a563cec7b068.doxdns5.com:
80.3.128.148:33383 TXID=33827
80.3.128.148:33421 TXID=26554
80.3.128.148:33406 TXID=40195
80.3.128.148:33373 TXID=9963
80.3.128.148:33330 TXID=37889
ISNOM:ISNOM TXID=ISNOM "
From Tesco.net, a Virgin reseller.
Check your named.conf for "query_source" and remove/comment that line. Other possible causes are the rc script calling rndc reconfig rather than kill/exec, which will leave the running process resident and just cause it to re-read the config. Manually /etc/init.d/named zap && /etc/init.d/named start (or is it /etc/init.d/dns on Genitals? I forget...) as big bad root. You may also have a firewall/router in the path of the 'net connection undoing all your nice port randomness.
Although the standard deviation test for randomness seems to give BT a POOR rating all the time, if you look at the scatter plots, there don't seem to be any obvious patterns (leastways there weren't when I ran the tests here), so I suspect that the BT servers are probably patched for this one.
Perhaps they have some way to limit the port range that they use in requests/responses, so it's a random selection from a (relatively) small pool - hence POOR as far as a standard deviation test is concerned?
Orange. On the DNS-OARC test, the source ports for the 2 Orange DNS's looked nonrandom. The plots of Source ports showed two parallel lines. This happened both for 193.36.79.100 (cache0.orange.net) and 193.36.79.101 (cache1.orange.net). The transaction ID plots are well scattered for both IP addresses. As Simon van der Walt reported, DNS-OARC says the results are great, but advises an eye check for randomness. Doxpara thinks the DNS's are ok, but advises a check for pattern and DNS-OARC shows the pattern.
Seeing as o2 data are 'aware of the situation' but seemingly unwilling to do anything about it, they are still wide open (193.113.200.171) so anyone browsing the net on an iPhone could start to have fun in the very near future.
You can only imagine the fun I had trying to get an answer out of them on the phone about when they were going to patch, and no, not the phone, the server...
1. 194.168.8.110 (winn-dnsbep-2.server.virginmedia.net) appears to have POOR source port randomness and GREAT transaction ID randomness.
2. 194.168.8.109 (winn-dnsbep-1.server.virginmedia.net) appears to have POOR source port randomness and GREAT transaction ID randomness.
Looking at the scatter plots it appears the source ports are randomised but within a very narrow range of 200 or so as opposed to the range of 65,000 or so which should be used. So the source port randomisation combined with the transaction ID randomness gives 8 + 16 = 24 bits of entropy compared to the 32 bits maximum possible. It is possible that Virgin Media may have other defences, e.g. against domains showing suspicious UDP packet storms involving many subdomains over a short duration.
"which idiot's idea was it to post vulnerable DNS severs here?!?"
Strong words based on a shallow analysis of the situation I feel.
a) The patch is available and, given it's severity, should have been implemented by now by anyone taking our money for ISP services - notwithstanding the possible costs or impact on network performance.
b) It's inevitable the 'baddies' will have access to this comments section - but that's offset by us mere mortal users being able to concur here and find out if we have a vulnerable ISP - there is no other source of reliable information other than the likes of this.
c) Do you honestly believe the 'black hat' community doesn't already have a comprehensive list already?
d) It's an unfortunate fact of life that an attack on an ISP, or an increase in suspicious traffic, is more likely to spur them to patch than a very clear technical warning - which they have already had.
Yes - on the face of it this exercise may appear foolish although to say so is plain crass. I see no horse in this stable - therefore I'll leave the door open as it stinks in here ....
Charles Johnson of LittleGreenFootballs [http://littlegreenfootballs.com/article/30617_DNS_Cache_Poisoning_Attacks]
posted an advisory Saturday, July 12. That day I made the switch in my router to OpenDNS.
DNS Resolver(s) Tested:
1. 208.69.36.14 (bld4.chi.opendns.com) appears to have GREAT source port randomness and GREAT transaction ID randomness.
Test time: 2008-08-01 12:19:59 UTC
Your ISP's name server, 68.87.77.132, has other protections above and beyond port randomization against the recently discovered DNS flaws. There is no reason to be concerned about the results seen below.Requests seen for 1c512a407263.doxdns5.com:
68.87.77.132:17745 TXID=56457
68.87.77.132:18005 TXID=8509
68.87.77.132:17599 TXID=51463
68.87.77.132:17774 TXID=3155
68.87.77.132:17487 TXID=15795
ISNOM:ISNOM TXID=ISNOM
This post has been deleted by its author
1. 168.150.253.2 (spoke.dcn.davis.ca.us) appears to have POOR source port randomness and POOR transaction ID randomness.
2. 168.150.253.1 (wheel.dcn.davis.ca.us) appears to have POOR source port randomness and POOR transaction ID randomness.
3. 168.150.193.10 (indra.omsoft.com) appears to have POOR source port randomness and GREAT transaction ID randomness.
Actually, one of their DNS servers seems not to work at all (there should be four entries here).
I've added information to their entry in the Davis Wiki since this is kind of a local issue.
When I originally tried the test on DoxPara, it said my name server looked ok, but to check that the port numbers didn't appear to follow a predictable pattern, which some of them did. Now it says "Your name server, at 71.250.0.38, may be safe, but the NAT/Firewall in front of it appears to be interfering with its port selection policy. The difference between largest port and smallest port was only 65."
These are the results of the other test:
1. 71.250.0.36 appears to have POOR source port randomness and GREAT transaction ID randomness.
2. 71.250.0.38 appears to have POOR source port randomness and GREAT transaction ID randomness.
3. 71.250.0.39 appears to have POOR source port randomness and GREAT transaction ID randomness.
I do things like pay my bills online, so the other day I called my ISP, FairPoint, to ask if they had addressed this problem. The number on their website actually connected me to Verizon tech support (from whom FairPoint recently bought the phone / internet business in this area). I spent something like an hour on the phone with them doing a lot of waiting and getting bounced around from person to person, and ultimately I got no information. The tech support people at this company are morons and had no idea what I was talking about and were unable to put me in touch with anyone who did.
So what do these results mean, am I in good shape or not?
The VM defaults were;
Ok on doxpara, and
poor/great on www.dns-oarc.net,
so I changed to OpenDNS servers;
doxpara seemed just as happy and
great/great on www.dns-oarc.net,
so happier here - unless this is all a great con and now my home network is getting added to another Bots'R'Us swarm.
ho hum
"offset by us mere mortal users being able to concur here and find out if we have a vulnerable ISP - there is no other source of reliable information other than the likes of this."
Precisely stated logic, the mainstay of all that is computing. The fact that it was posted to El Reg solidifies the argument very nicely.
Everyone else on here with an ISP using unpatched DNS and a story like Johnny Utah's should go to the OpenDNS site. Simply point your router or dialup client application to the safe DNSs offered therein.
Waiting for a fix from a hamhanded ISP who simply wants your money at the expense of your security deserves neither. But, if they are the only game in town, you don't have to use their dodgy DNSs. You will likely have to reboot your router, and or your PC to get the new DNS addresses to work.
http://www.opendns.com/
doxpara: Your ISP's name server, 89.101.160.5, has other protections above and beyond port randomization against the recently discovered DNS flaws.
dns-oarc: 1. 89.101.160.4 (ie-dub01a-dns01.upc.ie) appears to have GOOD source port randomness and GREAT transaction ID randomness. Test time: 2008-08-02 00:08:05 UTC
194.168.8.110 (winn-dnsbep-2.server.virginmedia.net) appears to have POOR source port randomness and GREAT transaction ID randomness.
80.3.64.148 (brig-dnsany-1.server.virginmedia.net) appears to have POOR source port randomness and GREAT transaction ID randomness.
194.168.8.109 (winn-dnsbep-1.server.virginmedia.net) appears to have POOR source port randomness and GREAT transaction ID randomness.
>> Whether or not 'my' DNS server is patched, if it queries an unpatched server for the IP of an unknown domain and the unpatched server has been poisoned for this domain then surely 'my' DNS cache becomes poisoned too.
No. The only way your server should query an unpatched server is when it is asking that unpatched server for authoritative data: ie when your server queries one of the name servers for google.com (say). Even if that google.com name server is unpatched, it will be serving authoritative data that it has loaded from disk. When it does that, the data it loads cannot be compromised by a cache poisoning attack. Besides, most authoritative servers don't *make* queries, they just answer them. If a DNS server doesn't make queries, it can't be spoofed and can't have its cache poisioned. Largely because it doesn't have a cache.
I've used the Paris icon because even she knows how DNS works
1. 62.189.58.210 (lnd4eusosrv39.lnd.ops.eu.uu.net) appears to have GREAT source port randomness and GREAT transaction ID randomness.
2. 62.189.34.89 (lnd10eusosrv175.lnd.ops.eu.uu.net) appears to have GREAT source port randomness and GREAT transaction ID randomness.
Looking good :D
Rogers - Canada - Too busy counting money - no time to patch....
Your name server, at 64.71.246.85, appears vulnerable to DNS Cache Poisoning.
All requests came from the following source port: 34212
Due to events outside our control, details of the vulnerability have been leaked. Please consider using a safe DNS server, such as OpenDNS. Note: Comcast users should not worry.Requests seen for 61c747213638.doxdns5.com:
64.71.246.85:34212 TXID=60558
64.71.246.85:34212 TXID=14499
64.71.246.85:34212 TXID=39035
64.71.246.85:34212 TXID=36982
64.71.246.85:34212 TXID=20736
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