PowerDNS Security Advisory 2019-03

[Erik Winkels <erik.winkels () open-xchange com>]

Hi all,

Today we released PowerDNS Authoritative Server 4.1.7 and 4.0.7, fixing an important security issue in the HTTP remote 
backend that has recently been reported to us [1].

The issue is that PowerDNS Authoritative Server, when the HTTP remote backend is used in RESTful mode (without post=1 
set), can be tricked by a remote user into connecting to an attacker-specified HTTP server 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.

This issue has been assigned CVE-2019-3871.

PowerDNS Authoritative up to and including 4.1.6 is affected.
Please note that at the time of writing, PowerDNS Authoritative 3.4 and below are no longer supported, as described in 
[2].

The full security advisory is provided below, and can also be found at [3].

We would like to thank Adam Dobrawy, Frederico Silva and GregoryBrzeski from HyperOne.com for finding and subsequently 
reporting this issue!

Minimal patches are available at [4].

[1]: https://github.com/PowerDNS/pdns/issues/7573
[2]: https://doc.powerdns.com/authoritative/appendices/EOL.html
[3]: https://docs.powerdns.com/authoritative/security-advisories/powerdns-advisory-2019-03.html
[4]: https://downloads.powerdns.com/patches/2019-03/

Best regards,
Erik Winkels

PowerDNS Security Advisory 2019-03: Insufficient validation in the HTTP remote backend
======================================================================================
-  CVE: CVE-2019-3871
-  Date: March 18th 2019
-  Affects: PowerDNS Authoritative up to and including 4.1.6
-  Not affected: 4.1.7, 4.0.7
-  Severity: High
-  Impact: Denial of Service, Information Disclosure, Content spoofing
-  Exploit: This problem can be triggered via crafted queries
-  Risk of system compromise: No
-  Solution: Upgrade to a non-affected version

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.

This issue has been assigned CVE-2019-3871.

PowerDNS Authoritative up to and including 4.1.6 is affected.
Please note that at the time of writing, PowerDNS Authoritative 3.4 and below are no longer supported, as described in 
https://doc.powerdns.com/authoritative/appendices/EOL.html .

We would like to thank Adam Dobrawy, Frederico Silva and Gregory Brzeski from HyperOne.com for finding and subsequently 
reporting this issue!

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