// For flags

CVE-2020-8903

Priviged Escalation in Google Cloud Platform's Guest-OSLogin

Severity Score

7.3
*CVSS v4

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

1
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

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.

Una vulnerabilidad en las versiones entre 20190304 y 20200507 de guest-oslogin de Google Cloud Platform, permite a un usuario al que solo se le otorga el rol "roles/compute.osLogin" para escalar privilegios a root. Al usar su membresía en el grupo "adm", los usuarios con este rol son capaces de leer el XID de DHCP desde el diario systemd. Con el XID de DHCP, es posible configurar la dirección IP y el nombre de host de la instancia en cualquier valor, que luego es almacenada en /etc/hosts. Un atacante puede luego apuntar a metadata.google.internal en una dirección IP arbitraria y suplantar al servidor de metadatos GCE que hace posible que el módulo PAM de inicio de sesión del Sistema Operativo otorgue privilegios administrativos. Todas las imágenes creadas después del 07 de mayo 2020 (20200507) están corregidas, y si no puede actualizar, le recomendamos editar /etc/group/security.conf y eliminar el usuario "adm" de la entrada de inicio de sesión del sistema operativo

*Credits: Chris Moberly
CVSS Scores
Attack Vector
Local
Attack Complexity
High
Attack Requirements
None
Privileges Required
Low
User Interaction
Active
System
Vulnerable | Subsequent
Confidentiality
High
High
Integrity
High
High
Availability
High
High
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Attack Vector
Local
Attack Complexity
Medium
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2020-02-12 CVE Reserved
  • 2020-06-22 CVE Published
  • 2023-03-08 EPSS Updated
  • 2024-08-04 CVE Updated
  • 2024-08-04 First Exploit
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
CWE
  • CWE-276: Incorrect Default Permissions
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Google
Search vendor "Google"
 Guest-oslogin
Search vendor "Google" for product "Guest-oslogin"
 >= 20190304.00 <= 20200507.00
Search vendor "Google" for product "Guest-oslogin" and version " >= 20190304.00 <= 20200507.00"
-
Affected
Opensuse
Search vendor "Opensuse"
 Leap
Search vendor "Opensuse" for product "Leap"
 15.1
Search vendor "Opensuse" for product "Leap" and version "15.1"
-
Affected
Opensuse
Search vendor "Opensuse"
 Leap
Search vendor "Opensuse" for product "Leap"
 15.2
Search vendor "Opensuse" for product "Leap" and version "15.2"
-
Affected