Synology Security Advisory SA-21:27 ISC BIND

Synology Inc. has published a security advisory concerning Synology DNS Server for NAS.

Publish time: 2021-11-01 18:33:53 UTC+8
Last updated: 2021-11-01 18:33:53 UTC+8
Severity: Moderate
Status: Ongoing

Mitigation
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Detail

CVE-2021-25219

• • Severity: Moderate

  • CVSS3 base score: 5.3

  • CVSS3 vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

  • In BIND 9.3.0 -> 9.11.35, 9.12.0 -> 9.16.21, and versions 9.9.3-S1 -> 9.11.35-S1 and 9.16.8-S1 -> 9.16.21-S1 of BIND Supported Preview Edition, as well as release versions 9.17.0 -> 9.17.18 of the BIND 9.17 development branch, exploitation of broken authoritative servers using a flaw in response processing can cause degradation in BIND resolver performance. The way the lame cache is currently designed makes it possible for its internal data structures to grow almost infinitely, which may cause significant delays in client query processing.

Reference

• ISC Releases Security Advisory for BIND

• CVE-2021-25219: Lame cache can be abused to severely degrade resolver performance

• CVE-2021-25219

Revision