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CVE: |
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CERT: |
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Posting date: |
2009-07-28 | ||
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Program Impacted: |
BIND | ||
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Versions affected: |
BIND 9 (all versions) | ||
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Severity: |
High | ||
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Exploitable: |
remotely | ||
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Summary: |
BIND denial of service (server crash) caused by receipt of a specific remote dynamic update message. | ||
Description:
Urgent: this exploit is public. Please upgrade immediately.
Receipt of a specially-crafted dynamic update message to a zone for which the server is the master may cause BIND 9 servers to exit. Testing indicates that the attack packet has to be formulated against a zone for which that machine is a master. Launching the attack against slave zones does not trigger the assert.
This vulnerability affects all servers that are masters for one or more zones – it is not limited to those that are configured to allow dynamic updates. Access controls will not provide an effective workaround.
dns_db_findrdataset() fails when the prerequisite section of the dynamic update message contains a record of type “ANY” and where at least one RRset for this FQDN exists on the server.
db.c:659: REQUIRE(type != ((dns_rdatatype_t)dns_rdatatype_any)) failed
exiting (due to assertion failure).
Workarounds:
(Some sites may have firewalls that can be configured with packet filtering techniques to prevent nsupdate messages from reaching their nameservers.)
Active exploits:
Solution:
Upgrade BIND to one of 9.4.3-P3, 9.5.1-P3 or 9.6.1-P1. These versions can be downloaded from:
Acknowledgment:
Matthias Urlichs for reporting the problem.
Tom Daly for methodical follow-on testing.
Revision History:
2009-07-28 Initial text
2009-07-29 Update to reflect Tom Daly's findings