A certain pseudo-random number generator (PRNG) algorithm that uses ADD with 0 random hops (aka βAlgorithm A0β), as used in OpenBSD 3.5 through 4.2 and NetBSD 1.6.2 through 4.0, allows remote attackers to guess sensitive values such as (1) DNS transaction IDs or (2) IP fragmentation IDs by observing a sequence of previously generated values. NOTE: this issue can be leveraged for attacks such as DNS cache poisoning, injection into TCP packets, and OS fingerprinting.
secunia.com/advisories/28819
www.securiteam.com/securityreviews/5PP0H0UNGW.html
www.securityfocus.com/archive/1/487658
www.securityfocus.com/bid/27647
www.trusteer.com/docs/OpenBSD_DNS_Cache_Poisoning_and_Multiple_OS_Predictable_IP_ID_Vulnerability.pdf
exchange.xforce.ibmcloud.com/vulnerabilities/40329
exchange.xforce.ibmcloud.com/vulnerabilities/41157