PT-2020-3611 · Powerdns+10 · Powerdns Recursor+10
Anat Bremler-Barr
+2
·
Published
2020-05-19
·
Updated
2026-03-06
·
CVE-2020-8616
CVSS v3.1
8.6
High
| Vector | AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H |
Name of the Vulnerable Software and Affected Versions
BIND versions prior to the fixed version
Windows DNS Server (affected versions not specified)
PowerDNS Recursor (affected versions not specified)
Description
The issue is related to a lack of effective limitation on the number of fetches performed when processing referrals, which can cause a recursing server to issue a large number of fetches. This can lead to degradation of the server's performance and potentially be exploited in a reflection attack with a high amplification factor. The vulnerability can be exploited by a remote attacker to trigger an assertion failure in tsig.c, causing a denial of service.
Recommendations
For BIND, update to a version that includes the fix for this issue.
For Windows DNS Server, apply the mitigation measures proposed by the vendor, as described in the security advisory ADV200009.
For PowerDNS Recursor, follow the guidance provided in the security advisory PowerDNS Advisory 2020-01.
As a temporary workaround, consider restricting the number of fetches performed when processing referrals to minimize the risk of exploitation.
Restrict access to the vulnerable
tsig.c function to prevent assertion failures until a patch is available.
At the moment, there is no information about a newer version that contains a fix for this vulnerability for some of the affected software.Exploit
Fix
DoS
Resource Exhaustion
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Weakness Enumeration
Related Identifiers
Affected Products
Alt Linux
Bind
Bind Server
Centos
Ibm Aix
Linuxmint
Powerdns Recursor
Red Hat
Suse
Ubuntu
Windows Dns Server