CVE-2023-4154: Samba's DirSync Control Implementation Design Flaw Exposes Passwords and Secrets in Active Directory

A critical design flaw has been identified in Samba's DirSync control implementation, leading to a potential exposure of sensitive passwords and secrets in Active Directory. Privileged users and Read-Only Domain Controllers (RODCs) can exploit this vulnerability, allowing them unauthorized access to all attributes, even in default setups. In some cases, the vulnerability can also result in access under low-privileged attacker influence.

Introduction

Samba, the popular open-source software suite enabling file and print sharing between Unix and Windows systems, has been found to have a design flaw in its DirSync control implementation. This flaw, designated as CVE-2023-4154, allows RODCs and users possessing the GET_CHANGES right to access all attributes, including sensitive secrets and passwords. The vulnerability can affect even default setups, potentially eliminating the distinction between RODCs and Domain Controller (DC) accounts. More alarmingly, the flaw fails to account for error conditions, granting access to secret attributes even under low-privileged attacker influence.

For more information about Samba and CVE-2023-4154, consult the following original references

1. Samba's official website: https://www.samba.org/
2. CVE-2023-4154 detailed information: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-4154
3. Details on Samba's DirSync control implementation: https://wiki.samba.org/index.php/Dirsync_Control
4. Samba's official documentation: https://www.samba.org/samba/docs/

Exploit Details

Here's a simplified representation of what an attacker could accomplish by exploiting the CVE-2023-4154 vulnerability:

// Step 1: An RODC or user with the GET_CHANGES permission connects to the affected Samba system

	connection = samba_connect(affected_system, username, password, domain);

// Step 2: The attacker requests all attribute values, including sensitive secrets and passwords, using the DirSync control

	results = samba_dirsync_request(connection, desired_attributes);

// Step 3: The attacker now has access to all attribute values, enabling them to potentially abuse this information for malicious purposes

	secret_attribute_values = results.get_secret_values();

Mitigation

To address this vulnerability, it is highly recommended that Samba administrators apply patches and updates as they become available from the Samba development team. Additionally, users should review their permission structures, ensuring that only trusted users and systems possess the GET_CHANGES right.

Conclusion

The CVE-2023-4154 vulnerability in Samba's DirSync control implementation poses a significant risk to the security of passwords and secrets in Active Directory environments. It is crucial for users and administrators to be aware of this vulnerability and to take prompt action to safeguard their systems against exploitation. By applying relevant patches and maintaining proper permissions, users can protect their networks from unauthorized access and potential abuse.

Timeline

Published on: 11/07/2023 20:15:08 UTC
Last modified on: 12/29/2023 05:15:08 UTC