Allele Security Alert
Insufficient validation in the HTTP remote backend
PowerDNS Authoritative up to and including 4.1.6
Proof of concept
An issue has been found in PowerDNS Authoritative Server when the HTTP remote backend is used in RESTful mode (without post=1 set), allowing a remote user to cause the HTTP backend to connect to an attacker-specified host instead of the configured one, via a crafted DNS query. This can be used to cause a denial of service by preventing the remote backend from getting a response, content spoofing if the attacker can time its own query so that subsequent queries will use an attacker-controlled HTTP server instead of the configured one, and possibly information disclosure if the Authoritative Server has access to internal servers.
Adam Dobrawy (HyperOne.com), Frederico Silva (HyperOne.com) and Gregory Brzeski (HyperOne.com)
PowerDNS Security Advisory 2019-03: Insufficient validation in the HTTP remote backend – PowerDNS Authoritative Server documentation
PowerDNS Security Advisory 2019-03
HTTP Remote Backend wrong host #7573
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Last modified: March 20, 2019