Template injection in Ansible

1) Code Injection

EUVDB-ID: #VU54626

Risk: High

CVSSv3.1: 7.1 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-3583

CWE-ID: CWE-94 - Improper Control of Generation of Code ('Code Injection')

Exploit availability: No

Description

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

The vulnerability exists due to improper input validation when processing yaml multi-line strings with ansible facts in templates. A remote attacker can trick the victim to open a specially crafted yaml template and execute arbitrary commands on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Ansible: 2.9.0 - 2.9.22

External links

http://github.com/ansible/ansible/blob/v2.9.23/changelogs/CHANGELOG-v2.9.rst#security-fixes
http://bugzilla.redhat.com/show_bug.cgi?id=1968412

Q & A

Can this vulnerability be exploited remotely?

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

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

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