OpenBSD PRNG weak security
| openbsd-prng-weak-security (40329) |  Low Risk |
Description:
OpenBSD could provide weaker than expected security, caused by a vulnerability in the pseudo random number generator (PRNG) that uses XOR and "Algorithm X3", where predictable sequence IDs are generated. By observing some consecutive transaction ID values, a remote attacker could exploit this vulnerability to guess the next DNS transaction ID and perform DNS Cache Poisoning.
Platforms Affected:
- OpenBSD, OpenBSD 2.8 - 4.2
Remedy:
Apply the appropriate update for your system. See References.
Consequences:
Gain Access
References:
- OpenBSD Web site, OpenBSD at http://www.openbsd.org/.
- Trusteer Web site, OpenBSD DNS Cache Poisoning and Multiple O/S Predictable IP ID Vulnerability at http://www.trusteer.com/docs/dnsopenbsd.html.
- BID-27647: OpenBSD PRNG DNS Cache Poisoning and Predictable IP ID Weakness
- CVE-2008-1146: A certain pseudo-random number generator (PRNG) algorithm that uses XOR and 3-bit random hops (aka Algorithm X3), as used in OpenBSD 2.8 through 4.2, allows remote attackers to guess sensitive values such as DNS transaction IDs by observing a sequence of previously generated values. NOTE: this issue can be leveraged for attacks such as DNS cache poisoning against OpenBSD's modification of BIND.
- SA28819: OpenBSD DNS Server PRNG Transaction ID Vulnerability
Reported:
Feb 06, 2008
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