CVE-2009-0696: BIND Dynamic Update DoS
BIND denial of service (server crash) caused by receipt of a specific remote dynamic update message.
28 Jul 2009
BIND 9 (all versions)
**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)) failedexiting (due to assertion failure).
(Some sites may have firewalls that can be configured with packet filtering techniques to prevent nsupdate messages from reaching their nameservers.)
An active remote exploit is in wide circulation at this time
Upgrade BIND to one of 9.4.3-P3, 9.5.1-P3 or 9.6.1-P1. These versions can be downloaded from:
Matthias Urlichs for reporting the problem. Tom Daly for methodical follow-on testing.
Document Revision History:
2009-07-28 Initial text 2009-07-29 Update to reflect Tom Daly's findings
See our BIND Security Matrix for a complete listing of Security Vulnerabilities and versions affected.
If you'd like more information on our Forum or product support please visit www.isc.org/support.
Do you still have questions? Questions regarding this advisory should go to email@example.com
Note: ISC patches only currently supported versions. When possible we indicate EOL versions affected.
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
This Knowledge Base article https://kb.isc.org/article/AA-00926 is the complete and official security advisory document.
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