Input validation error in pdns-recursor (Alpine package)

1) Input validation error

EUVDB-ID: #VU28142

Risk: Medium

CVSSv3.1: 4.2 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-12244

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a spoofing attack.

The vulnerability exists due to records in the answer section of a NXDOMAIN response lacking an SOA are not properly validated in SyncRes::processAnswer. A remote attacker with ability to perform a Man-in-the-Middle (MitM) attack can send a NXDOMAIN answer for a name that does exist and bypass DNSSEC validation.

Successful exploitation of the vulnerability may allow an attacker to perform a spoofing attack.

Mitigation

Install update from vendor's website.

Vulnerable software versions

pdns-recursor (Alpine package): 4.1.1-r0 - 4.1.14-r1

External links

http://git.alpinelinux.org/aports/commit/?id=5dcc709a2d71bb5090c2fdd2a78cab88d6395f1d
http://git.alpinelinux.org/aports/commit/?id=d863fb499f4f3c153298e54046738251d8fc1af5
http://git.alpinelinux.org/aports/commit/?id=fbfc29c6a052ada4d472ae1f42542c49ee9c5f86
http://git.alpinelinux.org/aports/commit/?id=b553aeeff9686aba5ada03399a14cd82d7675db3
http://git.alpinelinux.org/aports/commit/?id=4f995056d1cc52e27ae67abc42e4a53789c45fe2

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.