Privilege escalation in OpenSSH



| Updated: 2022-01-10
Risk Low
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2021-41617
CWE-ID CWE-269
Exploitation vector Local
Public exploit N/A
Vulnerable software
 OpenSSH
Server applications / Remote management servers, RDP, SSH

Vendor OpenSSH

Security Bulletin

This security bulletin contains one low risk vulnerability.

1) Improper Privilege Management

EUVDB-ID: #VU58333

Risk: Low

CVSSv4.0: 4.4 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

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

Install updates from vendor's website.

Vulnerable software versions

OpenSSH: 6.2 - 8.7p1

CPE2.3 External links

http://www.openwall.com/lists/oss-security/2021/09/26/1
http://www.openssh.com/txt/release-8.8
http://www.openssh.com/security.html
http://bugzilla.suse.com/show_bug.cgi?id=1190975
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/6XJIONMHMKZDTMH6BQR5TNLF2WDCGWED/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/W44V2PFQH5YLRN6ZJTVRKAD7CU6CYYET/
http://security.netapp.com/advisory/ntap-20211014-0004/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/KVI7RWM2JLNMWTOFK6BDUSGNOIPZYPUT/


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.

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.

The attacker would have to login to the system and perform certain actions in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

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



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