First published: Wed Oct 16 2019(Updated: )
Mirror zones are a BIND feature allowing recursive servers to pre-cache zone data provided by other servers. A mirror zone is similar to a zone of type secondary, except that its data is subject to DNSSEC validation before being used in answers, as if it had been looked up via traditional recursion, and when mirror zone data cannot be validated, BIND falls back to using traditional recursion instead of the mirror zone. However, an error in the validity checks for the incoming zone data can allow an on-path attacker to replace zone data that was validated with a configured trust anchor with forged data of the attacker's choosing. The mirror zone feature is most often used to serve a local copy of the root zone. If an attacker was able to insert themselves into the network path between a recursive server using a mirror zone and a root name server, this vulnerability could then be used to cause the recursive server to accept a copy of falsified root zone data. This affects BIND versions 9.14.0 up to 9.14.6, and 9.15.0 up to 9.15.4.
Credit: security-officer@isc.org
Affected Software | Affected Version | How to fix |
---|---|---|
ISC BIND | >=9.14.0<=9.14.6 | |
ISC BIND | >=9.15.0<=9.15.4 |
Upgrade to the patched release most closely related to your current version of BIND: + BIND 9.14.7 + BIND 9.15.5
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CVE-2019-6475 is a vulnerability in BIND that allows attackers to cause a denial of service (DoS) or potentially execute arbitrary code.
CVE-2019-6475 affects BIND versions 9.14.0 to 9.14.6 and versions 9.15.0 to 9.15.4. It allows recursive servers to pre-cache zone data provided by other servers, but the cached data is not properly validated against DNSSEC.
A mirror zone in BIND is a feature that allows recursive servers to pre-cache zone data provided by other servers.
The severity of CVE-2019-6475 is high, with a CVSS score of 7.5.
To fix CVE-2019-6475, update BIND to a version that includes the relevant security patches, such as versions 9.14.7 or 9.15.5.