CVE-2020-8903

Priviged Escalation in Google Cloud Platform's Guest-OSLogin

Published Jun 22, 2020 CVSS 4.0 · 7.3 High EPSS < 1% KEV · Not listed
Description
A vulnerability in Google Cloud Platform's guest-oslogin versions between 20190304 and 20200507 allows a user that is only granted the role "roles/compute.osLogin" to escalate privileges to root. Using their membership to the "adm" group, users with this role are able to read the DHCP XID from the systemd journal. Using the DHCP XID, it is then possible to set the IP address and hostname of the instance to any value, which is then stored in /etc/hosts. An attacker can then point metadata.google.internal to an arbitrary IP address and impersonate the GCE metadata server which make it is possible to instruct the OS Login PAM module to grant administrative privileges. All images created after 2020-May-07 (20200507) are fixed, and if you cannot update, we recommend you edit /etc/group/security.conf and remove the "adm" user from the OS Login entry.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2020-29742 A vulnerability in Google Cloud Platform's guest-oslogin versions between 20190304 and 20200507 allows a user that is only granted the role "roles/compute.osLogin" to escalate privileges to root. Using their membership to the "adm" group, users with this role are able to read the DHCP XID from the systemd journal. Using the DHCP XID, it is then possible to set the IP address and hostname of the instance to any value, which is then stored in /etc/hosts. An attacker can then point metadata.google.internal to an arbitrary IP address and impersonate the GCE metadata server which make it is possible to instruct the OS Login PAM module to grant administrative privileges. All images created after 2020-May-07 (20200507) are fixed, and if you cannot update, we recommend you edit /etc/group/security.conf and remove the "adm" user from the OS Login entry.
History

No history.

Weaknesses

Sources

Status
PUBLISHED
Assigner
Google
Published
Updated
Aug 4, 2024, 10:12 AM
Reserved
Feb 12, 2020, 12:00 AM
Status
Modified
Published
Jun 22, 2020, 2:15 PM
Modified
Jun 17, 2026, 3:27 AM