Denial of service in GnuPG

Published: 2019-06-29 | Updated: 2019-09-10

Risk	Medium
Patch available	YES
Number of vulnerabilities	1
CVE-ID	CVE-2019-13050
CWE-ID	CWE-297
Exploitation vector	Network
Public exploit	N/A
Vulnerable software Subscribe	SKS Keyserver Server applications / Other server solutions GnuPG Client/Desktop applications / Encryption software
Vendor	sks-keyservers.net GNU

Security Bulletin

This security bulletin contains one medium risk vulnerability.

1) Improper validation of certificate with host mismatch

EUVDB-ID: #VU20961

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-13050

CWE-ID: CWE-297 - Improper Validation of Certificate with Host Mismatch

Exploit availability: No

Description

The vulnerability allows a remote attacker to cause a persistent denial of service (DoS) condition on the target system.

The vulnerability exists due to the interaction between the vulnerable applications makes it risky to have a GnuPG keyserver configuration line referring to a host on the SKS keyserver network. A remote attacker can retrieve data from this network and cause a persistent denial of service, because of a certificate spamming attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

SKS Keyserver: 1.2.0

GnuPG: 1.0.0 - 2.2.16

External links

http://gist.github.com/rjhansen/67ab921ffb4084c865b3618d6955275f
http://lists.gnupg.org/pipermail/gnupg-announce/2019q3/000439.html

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.