title: A truncated TSIG response can lead to an assertion failure
description: In BIND 9.0.0 -> 9.11.21, 9.12.0 -> 9.16.5, 9.17.0 -> 9.17.3, also affects 9.9.3-S1 -> 9.11.21-S1 of the BIND 9 Supported Preview Edition, An attacker on the network path for a TSIG-signed request, or operating the server receiving the TSIG-signed request, could send a truncated response to that request, triggering an assertion failure, causing the server to exit. Alternately, an off-path attacker would have to correctly guess when a TSIG-signed request was sent, along with other characteristics of the packet and message, and spoof a truncated response to trigger an assertion failure, causing the server to exit.
problem types: Attempting to verify a truncated response to a TSIG-signed request leads to an assertion failure.  Affects BIND 9.0.0 -> 9.11.21, 9.12.0 -> 9.16.5, 9.17.0 -> 9.17.3, also affects 9.9.3-S1 -> 9.11.21-S1 of the BIND 9 Supported Preview Edition
affected:
{
product: BIND9
vendor: ISC
versions:
lessThan: unspecified, status: affected, version: 9.0.0, versionType: custom
lessThan: 9.11.22, status: affected, version: unspecified, versionType: custom
lessThan: unspecified, status: affected, version: 9.12.0, versionType: custom
lessThan: 9.16.6, status: affected, version: unspecified, versionType: custom
lessThan: unspecified, status: affected, version: 9.17.0, versionType: custom
lessThan: 9.17.4, status: affected, version: unspecified, versionType: custom
changes: [at: 9.11.22-S1, status: unaffected], lessThan: Supported Preview*, status: affected, version: 9.9.3-S1, versionType: custom
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: HIGH
baseScore: 6.5
baseSeverity: MEDIUM
confidentialityImpact: NONE
integrityImpact: NONE
privilegesRequired: LOW
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
version: 3.1
]
exploits: We are not aware of any active exploits
solutions: Upgrade to the patched release most closely related to your current version of BIND:
BIND 9.11.22
BIND 9.16.6
BIND 9.17.4
BIND Supported Preview Edition is a special feature preview branch of BIND provided to eligible ISC support customers.
BIND 9.11.22-S1
workarounds: No workarounds known.