Vulnerability identifier: #VU48379

Vulnerability risk: Low

CVSSv3.1: 5 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2020-16127

CWE-ID: CWE-835

Exploitation vector: Local

Exploit availability: Yes

Vulnerable software:
accountsservice (Ubuntu package)
Operating systems & Components / Operating system package or component

Vendor: Canonical Ltd.

Description

The vulnerability allows a local user to perform a denial of service (DoS) attack.

The vulnerability exists due to infinite loop in the "is_in_pam_environment" function. A local user can trigger an infinite loop by creating a symlink to "/dev/zero" and cause denial of service conditions.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

accountsservice (Ubuntu package): 0.6.1-1 - 0.6.55-0ubuntu12~20.04.1

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External links
http://securitylab.github.com/advisories/GHSL-2020-187-accountsservice-drop-privs-DOS

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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. However, proof of concept for this vulnerability is available.