Vulnerability identifier: #VU29236

Vulnerability risk: High

CVSSv3.1: 8.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-18934

CWE-ID: CWE-78

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Unbound
Server applications / DNS servers

Vendor: NLnet Labs

Description

The vulnerability allows a remote attacker to execute arbitrary shell commands on the target system.

The vulnerability exists due to insufficient validation of user-supplied input in the ipsec module. A remote attacker can pass specially crafted input to the application and execute arbitrary commands on the system.

Successful exploitation of he vulnerability requires that unbound is compiled with `--enable-ipsecmod` support, and ipsecmod is enabled and used in the configuration.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Unbound: 1.6.4 - 1.9.4

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External links
http://www.openwall.com/lists/oss-security/2019/11/19/1
http://github.com/NLnetLabs/unbound/blob/release-1.9.5/doc/Changelog
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/MOCR6JP7MSRARTOGEHGST64G4FJGX5VK/
http://www.nlnetlabs.nl/downloads/unbound/CVE-2019-18934.txt
http://www.nlnetlabs.nl/news/2019/Nov/19/unbound-1.9.5-released/

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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.