The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers). An example of a network attack is an attacker causing a denial of service by sending a specially crafted TCP packet across a wide area network (e.g., CVE-2004-0230).
Attack Complexity
Low
AC
The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Privileges Required
None
PR
The attacker is unauthenticated prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction
None
UI
The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges
Scope
Unchanged
S
An exploited vulnerability can only affect resources managed by the same security authority. In the case of a vulnerability in a virtualized environment, an exploited vulnerability in one guest instance would not affect neighboring guest instances.
Confidentiality
None
C
There is no impact on the confidentiality of the system; the attacker does not gain the ability to read any data.
Integrity
None
I
There is no impact on the integrity of the system; the attacker does not gain the ability to modify any files or information on the target system.
Availability
High
A
There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.
ISC Security Advisory:
Note: This email advisory is provided for your information. The most up to date advisory information will always be at:
http://www.isc.org/software/bind/advisories/cve-2012-1667
please use this URL for the most up to date advisory information.
Title: Handling of zero length rdata can cause named to terminate
unexpectedly
Processing of DNS resource records where the rdata field is zero length
may cause various issues for the servers handling them.
CVE: CVE-2012-1667
Document Version: 1.0
Posting date: 4 June 2012
Program Impacted: BIND
Versions affected: 9.0.x -> 9.6.x, 9.4-ESV->9.4-ESV-R5-P1,
9.6-ESV->9.6-ESV-R7, 9.7.0->9.7.6, 9.8.0->9.8.3, 9.9.0->9.9.1
Severity: Critical
Exploitable: Remotely
Description:
This problem was uncovered while testing with experimental DNS record
types. It is possible to add records to BIND with null (zero length)
rdata fields.
Processing of these records may lead to unexpected outcomes. Recursive
servers may crash or disclose some portion of memory to the client.
Secondary servers may crash on restart after transferring a zone
containing these records. Master servers may corrupt zone data if the
zone option "auto-dnssec" is set to "maintain". Other unexpected
problems that are not listed here may also be encountered.
Impact: This issue primarily affects recursive nameservers.
Authoritative nameservers will only be impacted if an administrator
configures experimental record types with no data. If the server is
configured this way, then secondaries can crash on restart after
transferring that zone. Zone data on the master can become corrupted if
the zone with those records has named configured to manage the DNSSEC
key rotation.
CVSS Score: 8.5
CVSS Equation: (AV:N/AC:L/Au:N/C:P/I:N/A:C)
For more information on the Common Vulnerability Scoring System and to
obtain your specific environmental score please visit:
http://nvd.nist.gov/cvss.cfm?calculator&adv&version=2&vector=(AV:N/AC:L/Au:N/C:P/I:N/A:C)
Workarounds:
Workarounds are under investigation, but none are known at this time.
Solution:
Upgrade to one of the following versions:
https://www.isc.org/software/bind/96-esv-r7-p1
https://www.isc.org/software/bind/976-p1
https://www.isc.org/software/bind/983-p1
https://www.isc.org/software/bind/991-p1
Exploit Status: No known active exploits but a public discussion of the
issue has taken place on a public mailing list.
Acknowledgment: Dan Luther, Level3 Communications, for finding the
issue, Jeffrey A. Spain, Cincinnati Day School, for replication and testing.
*Document Revision History: *
1.0 Released to Public 4 June, 2012
1.1 Updated Severity to Critical
References:
- Do you have questions? Questions regarding this advisory should go to
[email protected].
- ISC Security Vulnerability Disclosure Policy: Details of our current
security advisory policy and practice can be found here:
https://www.isc.org/security-vulnerability-disclosure-policy
See our BIND Security Matrix for a complete listing of Security
Vulnerabilites and versions affected.
Note: ISC patches only Currently supported versions. When possible we
indicate EOL versions affected.
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