Ubuntu update for openssh

1) Improper Privilege Management

EUVDB-ID: #VU58333

Risk: Low

CVSSv3.1: 6.1 [CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-41617

CWE-ID: CWE-269 - Improper Privilege Management

Exploit availability: No

Description

The vulnerability allows a local user to escalate privileges.

The vulnerability exists due to improper privilege management in sshd, when certain non-default configurations are used, because supplemental groups are not initialized as expected. Helper programs for AuthorizedKeysCommand and AuthorizedPrincipalsCommand may run with privileges associated with group memberships of the sshd process, if the configuration specifies running the command as a different user. A local user can escalate privileges on the system.

Mitigation

Update the affected package openssh to the latest version.

Vulnerable software versions

Ubuntu: 16.04

openssh-server (Ubuntu package): before Ubuntu Pro (Infra-only)

External links

http://ubuntu.com/security/notices/USN-5666-1

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

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