CVE-2020-8903: Priviged Escalation in Google Cloud Platform's Guest-OSLogin
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.
Affected Software
Remediation
Patch Available
Event History
Frequently Asked Questions
What is the severity of CVE-2020-8903?
CVE-2020-8903 is considered a high severity vulnerability due to the potential for privilege escalation to root.
How do I fix CVE-2020-8903?
To fix CVE-2020-8903, update Google Cloud Platform's guest-oslogin to a version later than 20200507.
What versions of guest-oslogin are affected by CVE-2020-8903?
CVE-2020-8903 affects guest-oslogin versions between 20190304 and 20200507.
Are there any specific distributions impacted by CVE-2020-8903?
Yes, openSUSE Leap 15.1 and 15.2 are specifically impacted by CVE-2020-8903.
What user role is exploited in CVE-2020-8903?
CVE-2020-8903 can be exploited by users granted the role 'roles/compute.osLogin' allowing them to escalate privileges.