TIPS FOR RELIABLE SPLIT-SECOND DNS REBINDING IN CHROME AND SAFARI

Summary from the TLDR InfoSec newsletter

DNS rebinding attacks occur when an attacker can trick a victim into leaking data by having the victim first communicate with the attacker's public server and then switching the DNS record to point to a private server. In Safari, a private IP address will be prioritized over a public IP address, but an attacker can circumvent this by delaying the DNS response with the private IP address. In Chrome, IPv6 will be prioritized over IPv4, allowing an attacker to send an IPv6 response with a public IP address and then an IPv4 response with a private IP address. In both cases, the attacker blocks the user from their server after connection, forcing the browser to rebind to the private IP.