The soft chewy center of the Internet
High-Volume Service
Alternatively, the attacker can use JavaScript to create a web page that triggers this attack, then the attacker can trigger a DNS lookup for http://www.your-bank.com and try to spoof packets with hostile data to the ISP's DNS server.
One more reason that this attack is so likely to succeed is that DNS is a high-volume service, with few sites logging incoming requests and answers, so detection of an attack is extremely unlikely. Attackers can simply hammer away at the server, making thousands of requests and spoofing replies until they succeed.
Are You Vulnerable?
Web-based and command-line tests check for this vulnerability. They generally trigger a number of DNS lookups that are examined, checking the port numbers and transaction IDs for randomness, and you can see the results quickly. Two web-based tests are available online [1][2].
Additionally, the DNS-OARC center offers a command line--based check that can be accessed with a tool such as dig or nslookup:
$ dig @ip.or.hostname +short porttest.dns-oarc.net TXT
To fix your vulnerability, you must update your DNS server; almost every vendor released an update in July. After you have updated your DNS server, and assuming you are using Bind, be sure that it is configured properly.
To do so, check your named.conf file and make sure you do not have something such as
query-source port 53; query-source-v6 port 53;
in it, but instead, something like:
query-source port *; query-source-v6 port *;
After you have updated, you should use one of the web-based or command-line tests to ensure it is working as expected.
Conclusions
DNS attacks illustrate both the limitations of some of the protocols in use on the Internet and the robustness inherent in the system, and it is unlikely this kind of attack will ever go away.
Even with the publicity surrounding this issue, a significant portion – upwards of 50 percent, according to some reports – of DNS servers still have not been fixed. Like spam, this kind of attack is something you will have to learn to live with.
Infos
- DoxPara: http://www.doxpara.com/
- DNS-OARC: http://www.dns-oarc.net/
« Previous 1 2 3
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
News
-
Fedora 40 Beta Released Soon
With the official release of Fedora 40 coming in April, it's almost time to download the beta and see what's new.
-
New Pentesting Distribution to Compete with Kali Linux
SnoopGod is now available for your testing needs
-
Juno Computers Launches Another Linux Laptop
If you're looking for a powerhouse laptop that runs Ubuntu, the Juno Computers Neptune 17 v6 should be on your radar.
-
ZorinOS 17.1 Released, Includes Improved Windows App Support
If you need or desire to run Windows applications on Linux, there's one distribution intent on making that easier for you and its new release further improves that feature.
-
Linux Market Share Surpasses 4% for the First Time
Look out Windows and macOS, Linux is on the rise and has even topped ChromeOS to become the fourth most widely used OS around the globe.
-
KDE’s Plasma 6 Officially Available
KDE’s Plasma 6.0 "Megarelease" has happened, and it's brimming with new features, polish, and performance.
-
Latest Version of Tails Unleashed
Tails 6.0 is based on Debian 12 and includes GNOME 43.
-
KDE Announces New Slimbook V with Plenty of Power and KDE’s Plasma 6
If you're a fan of KDE Plasma, you'll be thrilled to hear they've announced a new Slimbook with an AMD CPU and the latest version of KDE Plasma desktop.
-
Monthly Sponsorship Includes Early Access to elementary OS 8
If you want to get a glimpse of what's in the pipeline for elementary OS 8, just set up a monthly sponsorship to help fund its continued existence.
-
DebConf24 to be Held in South Korea
Busan will be the location of the latest DebConf running July 28 through August 4