#VU32136 Resource exhaustion in PowerDNS - CVE-2016-7068

Vulnerability identifier: #VU32136

Vulnerability risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2016-7068

CWE-ID: CWE-400

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
PowerDNS
Server applications / DNS servers

Vendor: PowerDNS.COM B.V.

Description

The vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.

An issue has been found in PowerDNS before 3.4.11 and 4.0.2, and PowerDNS recursor before 3.7.4 and 4.0.4, allowing a remote, unauthenticated attacker to cause an abnormal CPU usage load on the PowerDNS server by sending crafted DNS queries, which might result in a partial denial of service if the system becomes overloaded. This issue is based on the fact that the PowerDNS server parses all records present in a query regardless of whether they are needed or even legitimate. A specially crafted query containing a large number of records can be used to take advantage of that behaviour.

Mitigation
Install update from vendor's website.

Vulnerable software versions

PowerDNS: 3.4.0 - 3.7.3

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External links
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2016-7068
https://doc.powerdns.com/md/security/powerdns-advisory-2016-02/
https://www.debian.org/security/2017/dsa-3763
https://www.debian.org/security/2017/dsa-3764

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.