What is Spoofing?
Spoofing refers to the act of pretending to be someone else. In the context of the internet, there are two primary scenarios where spoofing can occur:
Pretending to be another user:
This involves accessing systems, sending documents, or encrypting communications under someone else's identity. For example, emails can be sent without authentication, allowing attackers to easily send messages under someone else's name or email address. To prevent such spoofing, senders can use their digital certificates, generate a digital signature with the private key paired with the public key in the certificate, and attach the signature to their communication. The recipient can verify the sender's identity by decrypting the signature using the public key in the certificate. However, for the digital certificate itself to be considered legitimate, it must be issued by a trusted certification authority managed by a third-party institution recognized for its reliability.
Spoofing the source IP address:
This method is widely used in attacks such as DoS/DDoS. In a DNS reflection attack, for instance, attackers spoof the source IP address to appear as the target site and send numerous requests to DNS servers. The DNS server sends back amplified responses (larger than the initial requests) to the target site, consuming the site’s network bandwidth and server resources, ultimately rendering it unavailable (denial of service).