The full name of DNS in English is Domain Name System, which refers to the domain name system and is also a service of the Internet. It is not only a popular target of network attacks, but also a very serious hidden danger in network security. The losses caused by DNS attacks every year are immeasurable, so we must pay attention to it. In order to avoid losses caused by DNS attacks, this article introduces the 5 most popular DNS attack methods and defense strategies, hoping to be useful to you.
1. DNS amplification attack
A DNS amplification attack is a popular form of DDoS attack in which a targeted system is flooded with query responses from public DNS servers. How it works: The attacker sends a DNS name query to a public DNS server, using the victim's address as the source address, causing the public DNS server's responses to be sent to the target system.
Attackers typically query as much domain name information as possible to maximize the amplification effect. By using botnets, attackers can also generate large numbers of fake DNS queries with little effort. Also, since the response is legitimate data from a valid server, it is difficult to prevent DNS amplification attacks.
2. DNS cache poisoning
In this type of attack, attackers exploit vulnerabilities in DNS servers to take them over. During cache poisoning, an attacker injects malicious data into a DNS resolver's cache system to redirect users to a website of their choice. Personal or other data is often stolen there.
If cybercriminals gain control of DNS servers, they can manipulate cached information. DNS cache poisoning code is often found in URLs sent via spam or phishing emails. DNS servers can access the caches of other DNS servers, so this type of attack can spread significantly. The main risk of DNS poisoning is data theft.
3. DNS tunnel
Another popular and well-experienced attack mode is DNS tunneling. These attacks leverage the DNS protocol to inject malware and other data using a client-server model. Using these data payloads, cybercriminals can take over a DNS server and then potentially access its administrative functions and applications residing on it.
DNS tunneling creates a hidden connection between the attacker and the target through the DNS resolver, which can bypass firewalls and be used for attacks such as data leakage. In most cases, DNS tunneling requires an infected system with external Internet access as a springboard to access an internal DNS server with network access.
4. Botnet reverse proxy
Fast Flux is a DNS evasion technique where attackers use botnets to hide their phishing and malware campaigns and evade security scans. The attacker would use the dynamic IP address of the infected host to act as a reverse proxy for the backend botnet host. Fast Flux can also make malware networks harder to detect by using a combination of peer-to-peer networking, distributed command and control, web-based load balancing, and proxy redirection.
5. DNS hijacking/redirection
DNS hijacking means bypassing name resolution for DNS queries. Cybercriminals use malware to modify the system's TCP/IP configuration to point to DNS servers they control to carry out DNS hijacking attacks. Alternatively, manipulate trusted DNS servers to run phishing campaigns.