OpenBSD ADD weak security
| openbsd-add-weak-security (41157) |  Low Risk |
Description:
OpenBSD and NetBSD could provide weaker than expected security, caused by a vulnerability in the pseudo random number generator (PRNG) that uses ADD and "Algorithm A0", where predictable sequence IDs are generated. By observing some consecutive transaction ID values, a remote attacker could exploit this vulnerability to guess the next IP fragmentation ID or the DNS transaction ID and perform DNS Cache Poisoning and OS fingerprinting.
*CVSS:
| Base Score: | 4.3 |
| Access Vector: | Network |
| Access Complexity: | Medium |
| Authentication: | None |
| Confidentiality Impact: | None |
| Integrity Impact: | Partial |
| Availability Impact: | None |
| Temporal Score: | 3.2 |
| Exploitability: | Unproven |
| Remediation Level: | Official-Fix |
| Report Confidence: | Confirmed |
Consequences:
Gain Access
Remedy:
Apply the appropriate update for your system. See References.
References:
- OpenBSD Web site: OpenBSD.
- The NetBSD Project Web site: The NetBSD Project.
- Trusteer Web site: OpenBSD DNS Cache Poisoning and Multiple O/S Predictable IP ID Vulnerability.
- BID-27647: OpenBSD PRNG DNS Cache Poisoning and Predictable IP ID Weakness
- CVE-2008-1148: A certain pseudo-random number generator (PRNG) algorithm that uses ADD with 0 random hops (aka Algorithm A0), 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.
- SA28819: OpenBSD DNS Server PRNG Transaction ID Vulnerability
Platforms Affected:
- NetBSD NetBSD 1.6.2
- NetBSD NetBSD 2.0
- NetBSD NetBSD 2.0.1
- NetBSD NetBSD 2.0.2
- NetBSD NetBSD 2.0.3
- NetBSD NetBSD 2.0.4
- NetBSD NetBSD 2.1
- NetBSD NetBSD 2.1.1
- NetBSD NetBSD 3.0.1
- NetBSD NetBSD 3.0.2
- NetBSD NetBSD 3.1 rc2
- NetBSD NetBSD 3.1
- NetBSD NetBSD 3.1 rc1
- NetBSD NetBSD 4.0 beta2
- NetBSD NetBSD 4.0
- NetBSD NetBSD 4.0 beta
- OpenBSD OpenBSD 3.5 - 4.2
Reported:
Feb 06, 2008
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For corrections or additions please email xforce@iss.net
* According to the Forum of Incident Response and Security Teams (FIRST), the Common Vulnerability Scoring System (CVSS) is an "industry open standard designed to convey vulnerability severity and help to determine urgency and priority of response." IBM PROVIDES THE CVSS SCORES "AS IS" WITHOUT WARRANTY OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. CUSTOMERS ARE RESPONSIBLE FOR ASSESSING THE IMPACT OF ANY ACTUAL OR POTENTIAL SECURITY VULNERABILITY.
The information within this database may change without notice. Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. In no event shall IBM be held liable for any damages whatsoever arising out of or in connection with the use or spread of this information.