Yuan Wang on LinkedIn: DNS cache poisoning, also known as DNS spoofing, is a type of cyber attack… (2024)

DNS cache poisoning, also known as DNS spoofing, is a type of cyber attack where malicious actors manipulate the DNS (Domain Name System) cache to redirect internet traffic from a legitimate website to a fraudulent one. Here’s how it typically works:DNS Resolution Process: When you type a web address into your browser, your computer sends a request to a DNS server to resolve the human-readable address (like www*example*com) into an IP address (like 192*0*2*1).Caching: To speed up the resolution process, DNS servers and even your own computer store (or cache) the results of previous DNS lookups for a certain period of time. This means if you visit the same website again, the DNS lookup can be served from the cache instead of querying the DNS server again.Poisoning the Cache: In a DNS cache poisoning attack, the attacker exploits vulnerabilities in the DNS software or protocol to insert incorrect DNS records into the cache. This means that when a user tries to visit a legitimate site, the poisoned cache serves the wrong IP address, leading the user to a malicious site instead.Methods of DNS Cache PoisoningID Prediction: Each DNS query has a transaction ID, which should be unique. If an attacker can predict or guess this ID, they can send a forged response to the DNS resolver before the legitimate response arrives.Cache Flushing: Attackers can force the DNS resolver to flush its cache by sending a large number of DNS requests, creating an opportunity to insert fake DNS records when the cache is rebuilt.Exploiting Vulnerabilities: Vulnerabilities in DNS software can be exploited to insert malicious entries directly into the DNS cache.Consequences of DNS Cache PoisoningPhishing: Redirecting users to fake websites designed to steal login credentials, financial information, or personal data.Malware Distribution: Redirecting users to sites that download and install malware on their devices.Man-in-the-Middle Attacks: Intercepting and altering communication between the user and the intended website.Mitigations and DefensesDNSSEC (DNS Security Extensions): Adds cryptographic signatures to DNS data, ensuring that the responses to DNS queries are authentic and haven't been tampered with.Randomized Source Ports: Using random source ports for DNS queries makes it harder for attackers to predict the details needed for a successful attack.Cache Management: Regularly clearing and refreshing DNS caches to minimize the risk of long-term poisoning.Security Patches: Keeping DNS software and infrastructure up-to-date with the latest security patches and updates.Monitoring and Alerts: Implementing monitoring and alert systems to detect unusual DNS activity that could indicate an attack.By understanding and implementing these practices, organizations and individuals can protect themselves from the potentially severe consequences of DNS cache poisoning attacks.image credit cyberwrite

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