Summary: A security vulnerability, designated as CVE-2023-3899, has been discovered in the subscription-manager software used for handling virtual and physical systems. This vulnerability enables a low-privileged local user to tamper with the state of the registration, potentially unregistering the system or changing current entitlements. As a result, the attacker can achieve a local privilege escalation to an unconfined root. This article provides details on the vulnerability, implications, related code snippets, and links to original references.

Details of the Vulnerability

The subscription-manager is an application used to manage Red Hat subscriptions and registered systems. It interacts with the Red Hat subscription management platform to provide a convenient component for handling subscriptions for physical and virtual systems.

The vulnerability, CVE-2023-3899, was found in the subscription-manager that allows local privilege escalation due to inadequate Authorization. The D-Bus interface com.redhat.RHSM1 exposes a significant number of methods to all users that could change the state of the registration. The flaw resides in the com.redhat.RHSM1.Config.SetAll() method.

By exploiting this vulnerability, a low-privileged user can tamper with the state of the registration by unregistering the system or changing the current entitlements. In addition, the attacker can set arbitrary configuration directives for /etc/rhsm/rhsm.conf, which can be abused to cause a local privilege escalation to an unconfined root.

Code Snippet: Exploiting com.redhat.RHSM1.Config.SetAll() Method

The following code snippet demonstrates how to exploit the vulnerability in the com.redhat.RHSM1.Config.SetAll() method:

import dbus

RHSM_BUS_NAME = "com.redhat.RHSM1"
RHSM_CONFIG_OBJECT = "/com/redhat/RHSM1/Config"
RHSM_CONFIG_INTERFACE = "com.redhat.RHSM1.Config"

bus = dbus.SystemBus()
rhsm_config_object = bus.get_object(RHSM_BUS_NAME, RHSM_CONFIG_OBJECT)
rhsm_config = dbus.Interface(rhsm_config_object, RHSM_CONFIG_INTERFACE)

config_data = {"some_key": "some_value"}
rhsm_config.SetAll(config_data)

By modifying the config_data dictionary in the code above, an attacker can inject arbitrary configurations into the /etc/rhsm/rhsm.conf file.

Implications of the Vulnerability

The implications of this vulnerability can be severe, as it allows attackers to escalate their privileges and perform unauthorized actions on the affected systems. This could include the unauthorized access of sensitive data or the ability to execute arbitrary code with elevated privileges, among other nefarious activities.

If exploited successfully, this vulnerability can lead to

1. Unauthorized changes to the system's registration state, which could impact support and services provided by Red Hat.
2. Arbitrary changing of entitlements, potentially allowing unauthorized access to software and updates.

For more information on this vulnerability and to further understand its impact, refer to

1. Red Hat Bugzilla Entry - the original bug report with more detailed information about the issue and related discussion.
2. CVE-2023-3899 on NVD - the detailed record on the National Vulnerability Database with vulnerability specifics and related resources.

As a temporary mitigation measure, administrators can restrict access to the D-Bus system bus and the associated com.redhat.RHSM1 interface. It is, however, recommended to update to the latest version of the subscription-manager software, which contains patches to address this vulnerability.

Timeline

Published on: 08/23/2023 11:15:07 UTC
Last modified on: 11/09/2023 20:11:15 UTC