The DNS protocol, as implemented in (1) BIND 8 and 9 before 9.5.0-P1, 9.4.2-P1, and 9.3.5-P1; (2) Microsoft DNS in Windows 2000 SP4, XP SP2 and SP3, and Server 2003 SP1 and SP2; and other implementations allow remote attackers to spoof DNS traffic via a birthday attack that uses in-bailiwick referrals to conduct cache poisoning against recursive resolvers, related to insufficient randomness of DNS transaction IDs and source ports, aka “DNS Insufficient Socket Entropy Vulnerability” or “the Kaminsky bug.”