SB2020090137 - Ubuntu update for keystone

Description

This security bulletin contains information about 4 secuirty vulnerabilities.

1) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2020-12689)

The vulnerability allows a remote attacker to escalate privileges on the system.

The vulnerability exists due to application does not properly impose security restrictions, which leads to security restrictions bypass and privilege escalation. Any user authenticated within a limited scope (trust/oauth/application credential) can create an EC2 credential with an escalated permission, such as obtaining admin while the user is on a limited viewer role. This potentially allows a malicious user to act as the admin on a project another user has the admin role on, which can effectively grant that user global admin privileges.

2) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2020-12691)

The vulnerability allows a remote attacker to escalate privileges on the system.

The vulnerability exists due to application does not properly impose security restrictions, which leads to security restrictions bypass and privilege escalation. Any authenticated user can create an EC2 credential for themselves for a project that they have a specified role on, and then perform an update to the credential user and project, allowing them to masquerade as another user. This potentially allows a malicious user to act as the admin on a project another user has the admin role on, which can effectively grant that user global admin privileges.

3) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2020-12690)

The vulnerability allows a remote attacker to escalate privileges on the system.

The vulnerability exists due to application does not properly impose security restrictions, which leads to security restrictions bypass and privilege escalation. The list of roles provided for an OAuth1 access token is silently ignored. Thus, when an access token is used to request a keystone token, the keystone token contains every role assignment the creator had for the project. This results in the provided keystone token having more role assignments than the creator intended, possibly giving unintended escalated access.

4) Missing Required Cryptographic Step (CVE-ID: CVE-2020-12692)

The vulnerability allows a remote attacker to intercept and decrypt sensitive information.

The vulnerability exists due to the EC2 API does not have a signature TTL check for AWS Signature V4. An attacker can sniff the Authorization header, and then use it to reissue an OpenStack token an unlimited number of times.

Remediation

Install update from vendor's website.

References

• https://ubuntu.com/security/notices/USN-4480-1