Synology-SA-21:27 ISC BIND
Publish Time: 2021-11-01 18:33:53 UTC+8
Last Updated: 2022-11-09 18:09:45 UTC+8
- Severity
- Moderate
- Status
- Accepted
Abstract
A vulnerability allows remote attackers to conduct denial-of-service attacks via a susceptible version of Synology DNS Server.
Affected Products
| Product | Severity | Fixed Release Availability |
|---|---|---|
| DNS Server for DSM 7.0 | Moderate | Upgrade to 9.16.23-6117 or above. |
| DNS Server for DSM 6.2 | Moderate | Will not fix |
| DNS Server for SRM 1.2 | Moderate | Will not fix |
Mitigation
If you need immediate assistance, please contact Synology technical support via https://account.synology.com/support.
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
| Revision | Date | Description |
|---|---|---|
| 1 | 2021-11-01 | Initial public release. |
| 2 | 2022-02-17 | Update for DNS Server for DSM 7.0 is now available in Affected Products. |