The Domain Name System (DNS) translates Internet domain and host names to IP addresses.

learn more… | top users | synonyms

23
votes
3answers
882 views

What are some risks of purchasing a “used” domain name

If you purchase an existing domain name that was already used by someone else what are the ways in which the domain could have been broken by the previous owner? Are such problems common and are there ...
20
votes
6answers
3k views

Why do DDoS attacks cost a fortune to stop?

I have read so many stories that a major DDoS attack is causing companies thousands of dollars to mitigate. I have two questions: Is this because they try to keep the servers accessible to real site ...
18
votes
3answers
5k views

DNS Amplification DDOS attack

During the weekend I made some tests to simulate an DNS Amplification DDOS attack. sending about 90Mb/s traffic I was able to generate about x.x Gb/s amplified traffic which sent our datacenter ...
17
votes
4answers
677 views

Global Blackout is a myth?

In order to shut the Internet down, anonymous claimed that putting-down the 13 root DNS servers of the Internet and therefore disabling the HTTP Internet, the most widely used function of the Web, ...
17
votes
5answers
7k views

Do you detect/react to DNS tunnelling?

I've just seen a talk about tunnelling TCP/IP over DNS requests, because port 53 UDP is usually open and unfiltered. What techniques exist to detect and block such tunnels, and have you ever seen that ...
15
votes
7answers
1k views

Would it be possible to overload a large part of the internet, and if so then how?

Last week a news article went viral about a Dutch web hosting/data center company that was allegedly using a DNS amplification attack to DDoS an anti-spam company, because they blacklisting the ...
14
votes
7answers
2k views

Can a HTTPS connection be compromised because of a rogue DNS server

If I'm visiting (just a desktop pc, client side) a site that has a valid HTTPS cert/connection, that can it be compromised if I'm using [not with free will, so e.g.: I'm "attacked"] a rouge DNS ...
14
votes
5answers
2k views

Can I avoid DNS spoofing by typing the IP address?

The question is in the title. I have been reading about DNS spoofing. What if I were to save the IP addresses of websites I consider sensitive and then just enter the IP address when I am using a ...
14
votes
3answers
832 views

Do any DNS registrars support multi factor authentication?

I am looking for a DNS registrar that supports strong multi-factor authentication. Does any DNS registrar support multi-factor? Is this a legitimate need?
13
votes
4answers
4k views

Does Tor Hidden Service Protocol provide more threat protection than a standard HTTPS session?

DuckDuckGo is a search engine that has a Tor Exit Enclave and hidden service. This site is focused on the safe, secure searching of its users. Since DNS is not used in Tor, it appears that HTTPS is ...
11
votes
0answers
146 views

DNSSEC signing algorithms

Virtualmin supports a flurry of algorithms for DNSSEC: RSASHA1, RSASHA256, RSAMD5, DSA, DH, HMAC-MD5, NSEC3RSASHA1, NSEC3DSA. If I understand correctly, there's Proof of Concept available for SHA1 ...
10
votes
4answers
4k views

Is NTP vulnerable to DNS poisoning or spoofing attacks?

Scenario: Attacker somehow compromises the DNS lookup for the NTP server used by the victim (a web application) Victim sends DNS request for e.g. ntp.pool.org, which is responded to by attacker to ...
9
votes
2answers
2k views

Is the Google address being spoofed on my computer?

I might use some inappropriate terminology because I am no expert, but please feel free to correct me where it is needed. I believe that a process has modified some network file on my computer, like ...
9
votes
3answers
3k views

DNSSec (comcast) vs DNSCurve (OpenDNS)

I was previously using OpenDNS on my internal network. I found out today that comcast has switched over to DNSSec:Comcast DNSSec. I've did a little research on DNSSec and its benefits. I ...
8
votes
3answers
347 views

Why is RFC4255 (SSHFP) not used for https?

I had this idea a few hours ago, but of course it already exists and there is even an RFC... Why don't we publish the fingerprint for the SSL/TLS certificate via DNS? We need DNSSEC to make sure the ...
8
votes
3answers
18k views

How can I identify open DNS resolvers in my network?

This article highlights how open DNS resolvers are being used to create DDOS attacks across the internet. How can I identify whether any of our DNS servers are open? If I find that we are running ...
8
votes
2answers
10k views

DNS zone transfer attack

Hello Guys! Can anyone explain what is DNS zone transfer or give any link, paper? I have already googled, but could not find anything meaningful?
7
votes
2answers
2k views

How does DNSSec work? Are there known limitations or issues?

Based on information from this site, DNSSec is needed to protect us from a number of DNS and SSL / TLS hacks, including: DNS spoofing, especially on wifi or shared medium Registrars that abuse their ...
7
votes
4answers
185 views

DNS spoofing of linux distribution repositories

Question(s) Is it possible to "redirect" linux-update-repos via DNS spoofing (e.g. DNS cache poisoning) to a malicious website, so that harmful software (updates) will be installed, when running the ...
7
votes
2answers
407 views

How to protect and detect DNS manipulations from browser side?

After reading the question about a manipulated google analytics script I wonder how you would protect against this kind of attack. What comes to mind is setting DNS IP fixed in network configuration ...
7
votes
2answers
2k views

How can someone sinkhole domains?

The Wikipedia article about CryptoLocker says: In late-October 2013, security vendor Kaspersky Labs reported that with the help of a researcher, it had created a DNS sinkhole to block some of the ...
6
votes
3answers
494 views

Security implications of an exploited router

So I completely understand that routers and local networks need to be kept locked down, etc. What real security threats can come about from an attacker who has remotely accessed (telnet or web gui) ...
6
votes
7answers
19k views

Are services like Hide My Ass and UnoDNS reasonably safe to use?

While in Germany, I want to keep using my Netflix account, watch PBS, CNBC. I have found following services: A VPN: https://hidemyass.com/vpn/promo/1/5/ A DNS: http://www.unotelly.com/unodns/ I an ...
6
votes
2answers
2k views

Initial steps of network mapping

In light of recent security breaches hitting the news, it's been all hands on deck at my work as far as security. I'm trying to pen test our network. I have a very basic question. My Question You ...
6
votes
2answers
1k views

Could somebody explain how DNS poisoning might occur in this scenario?

I read the following statement in a security blog using the same source port over and over again for dns queries instead of randomizing them is a vulnerability for dns poisoning Could somebody ...
6
votes
3answers
2k views

What's involved in taking over someone else's domain name?

I'm asking this for purely academic reasons. I know that there are domain record lists and whatnot, but I'm trying to understand the exact structure of how DNS works and where someone can potentially ...
6
votes
1answer
4k views

Which security risks are associated with alternative DNS providers?

I'm considering using an alternative DNS provider on my computer. Which risks do I run if I use one? I already know that the DNS provider may return a malicious IP address when I'm trying to access ...
6
votes
4answers
10k views

Pros/cons of using a private DNS vs. a public DNS

I was wondering why a company should use a private DNS. In comparison with a public DNS, which advantages does a private one have, and which issues can a public DNS create for a company? I'm new at ...
6
votes
3answers
657 views

Does NAT break source port randomization?

The standard defense against the Kaminsky attack is to use source port randomization for all DNS requests. Does NAT break the security benefits of source port randomization? In more detail, consider ...
6
votes
3answers
579 views

Is the Kaminsky bug still a problem for sites without DNSSEC?

I have read about the Kaminsky bug, but I don't fully understand how easy it is to use this vulnerability for an attacker. Are DNS-software updated now so it's not that easy to use this vulnerability ...
6
votes
1answer
1k views

DSL Modem Compromised?

Just found out that the primary & secondary DNS servers have been changed to 95.211.156.101 & 5.45.75.11. I had the following setup in place. MAC filtering and WPA2 for WiFi. ...
6
votes
1answer
754 views

Should content delivery depend on FCrDNS (forward-confirmed reverse DNS) look-ups and why?

First, let me clear that this isn't a duplicate of Does deliberately wrong information from a DNS server violate standards generally accepted good practices? thread, as I'm not interested in legal ...
6
votes
2answers
2k views

How bad is the leaking of Internal IP addresses through external DNS

If an external DNS server is leaking internal IP addresses are there any significant security threats associated with this information leakage? Apart from most the obvious - gaining an understanding ...
6
votes
1answer
3k views

How to create your own RBL DNS Blacklist to prevent spam

I am getting sick of reporting the same old chinese emails to Spamcop now and would like to make my own small RBL list that I can easily add blocks of IP's to. I have a spare PC and static IP address ...
6
votes
1answer
181 views

Attack on authoritative DNS server with high TTLs

The way DNS works, resolvers cache query results per TTL defined in the response. Consider an authoritative DNS server that is compromised, its main A record set to a different IP and TTL of that ...
5
votes
5answers
5k views

Why can we not block DNS Amplification attack by blocking UDP packets or DNS response packet?

I mean if the attacker tries to ask all the open DNS resolver respond to a web server. The web server can just block its UDP ports. If the all the DNS response go to a Authoritative ...
5
votes
2answers
631 views

How does dnsleaktest.com find my DNS provider

Can't see how they find this over the web. I'm on Windows, its in my network config. It changes when I use a VPN provider, but not when I use a local socks proxy connected to a remote server over ...
5
votes
2answers
6k views

How can I detect/withstand DNS amplification attack?

I am a developer, and I am trying to get an insight into what could I do to enable my application to withstand a DNS amplification kind of attacks. Would such prevention methods help against DOS type ...
5
votes
1answer
218 views

Kaminsky Bug Exploitation

I am trying to exploit the Kaminsky bug for a school assignment. The specific version of the bug that I want to exploit is sending a forged packet with false information about www.domain.com so that ...
5
votes
3answers
580 views

How dangerous is it that there are DNS entries for our domain that we did not register?

I was performing an DNS brute-force on our company's domain and found entries like "html" "ww" and "wwww" resolving to IPs outside of our registered block. This sparked a debate about just how ...
5
votes
1answer
6k views

DNS Spoofing vs DNS Cache Poisoning

What is the difference between DNS Spoofing and DNS Cache Poisoning ??? It seems like there are little differences between two attacks, with an exception that DNS server is actually might cache the ...
5
votes
3answers
899 views

Why would you want to run DNS servers externally?

Something that's never made much sense to me is when environments have DNS servers which are publicly accessible (on the internet). This more often than not seems to leave them vulnerable to Cache ...
5
votes
1answer
2k views

What are the privacy pros and cons of using a public DNS server vs. your own?

Whether I'm using a normal internet connection setup, or tunnelling it through an anonymizing VPN or through TOR, what information of mine is revealed to whatever DNS server that I choose (e.g. Google ...
5
votes
2answers
2k views

Is it safe to have a DNS record pointing to 127.0.0.1?

My development server is on my local machine (127.0.0.1). I have created an A record in my DNS settings that points dev.mydomain.com to 127.0.0.1 so that I can use this domain name for accessing my ...
5
votes
4answers
452 views

Is it harmful to redirect web bugs to localhost on hosts file?

I was checking the article hosts file on Wikipedia, and I found this: Blocking access to servers of unwanted content by redirecting them to the local host (127.0.0.1) may have security ...
5
votes
1answer
230 views

What is the status of forced HTTPS everywhere (Strict transport security) via DNS? I only see last years draft

I'm trying to find the most recent RFC on HSTS in DNS (or rather said DNSSEC), but can only find this year old one in expired draft status Where can I find the most current guidance on STS in DNS? If ...
5
votes
2answers
347 views

Is this a DNS attack?

The following graph shows the UDP DNS queries/sec (blue) and DNS responses/sec (red) of traffic passing a router over the preiod of 4 days. DNS query is a DNS packet with query/response flag set to 0 ...
5
votes
1answer
2k views

Implications of using DNS Forwarders instead of Root Hints

When redesigning an organizations DNS infrastructure, the question of using Forwarders instead of Root Hints comes up. What kinds of issues should I be aware of when the admins and designers start ...
4
votes
4answers
958 views

Does using Google DNS make extensions like AdBlock Plus useless?

As many of you probably do, I am not using my ISP DNS because of very low performance, and I am using Google's primary and secondary DNS (8.8.8.8 and 8.8.4.4) which are good speed-wise but, knowing ...
4
votes
3answers
5k views

To DMZ, or not to DMZ

So for an assignment, we need to create a scheme (and eventually also the set-up) of a couple of servers in a network. The 'networks' are: Internal network DMZ The internet And the servers we ...