Domain Name System

1
What is DNS Attack?

• Indeed, DNS attacks happen when a hacker is able
  to find weaknesses to exploit in the DNS (Domain
  Name System).
• Hackers take advantage of vulnerabilities make
  DNS attack possible. In order to understand, how
  DNS attacks actually work, you will have to first
  understand how DNS works.
• For those who dont know, domain name system is
  a protocol that interprets an alphabetic domain
  name into IP address. In short, its major
  function is to convert a user-friendly domain
  name into the computer-friendly IP address.

2
How DNS Works?

• When a user types a domain name in the browser, a
  program available in the operating system known
  as DNSresolver searches for IP address of that
  domain name.
• First, DNS resolver searches its own local cache
  and check if it already has the IP address for
  that domain. If it does not find it in the local
  cache, It queries a DNS server to check if it
  knows the accurate IP address for that domain.
• DNS servers work in a loop which means they are
  able to query each other to find the DNS server
  that knows the correct IP address of the domain
  name.

3
How DNS Works?

• As soon as DNS resolver locates the IP address,
  it returns the IP address to requesting program.
  DNS caches domain address for future use as well.
• Though Domain Name System is quite powerful yet
  it seems less focused toward the security. Maybe
  thats why we are noticing different types of DNS
  attack.
• To minimize the possibilities of DNS attack,
  server administrators must take some necessary
  steps. They can use an upgraded version of DNS
  software and regularly configure servers to
  duplicate. At a personal level, users can flush
  their DNS cache to avoid security risks. If you
  dont know how to flush DNS, read a resourceful
  post at ICSS India.

4
How Hackers Use DNS?

• The biggest issues with DNS system is that if on
  any account a hacker is able to find a way to
  replace the authorized IP address of a website
  with rogue IP address, then any person trying to
  access that website will be sent to a bogus
  address. The user would not have any idea that he
  is accessing the wrong address.
• One of the major problems with DNS  server
  configuration is that it does not remember its
  default configuration. Attackers take advantage
  of this loophole.

5
Thank You

• For more information you can visit us at
• International College For Security Studies
• ( Cyber Security ICSS )