BIND 9 DoS vuln

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A vulnerability affecting BIND (Berkeley Internet Name Domain) servers running versions 9 to 9.2.0 can cause an abort condition which requires a re-start to restore service. Versions 4, 8 and 9.2.1 are not affected. There does not appear to be any potential for remote compromise.

According to the CERT/CC advisory "the internal consistency check that triggers the shutdown occurs when the rdataset parameter to the dns_message_findtype() function in message.c is not NULL as expected. The condition causes the code to assert an error message and call abort() to shut down the BIND server."

According to the ISS advisory, "under normal operating conditions, the rdataset variable is non-null. This exploit forces rdataset to be null, or empty, which causes an error and calls abort(), which shuts down the server."

CERT's wording is a bit weird and appears to contradict ISS. In any event, you can download version 9.2.1 here and be done with it. But check out the BIND 9 users' mailing list archives first, and see what you think about using it in a production environment.

Most flavors of Linux have shipped at least some editions with the vulnerable versions, so you should check with your vendor. The CERT advisory contains a brief list of vendors' reports on their products' status, which appears to be incomplete at the moment. Briefly, IBM, Sun, MS and Apple all say you've got nothing to worry about. ®

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