EUVD-2023-37370

Comprehensive Technical Analysis of EUVD-2023-37370

1. Vulnerability Assessment and Severity Evaluation

The vulnerability described in EUVD-2023-37370 affects Emby Server, a popular home media server solution. The issue allows an attacker to gain administrative access to the Emby Server system by spoofing certain headers intended for interoperation with reverse proxy servers. This can result in bypassing password authentication or viewing a list of user accounts, potentially exposing accounts with no password configured.

Severity Evaluation:

• CVSS Base Score: 9.1
• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

The high base score of 9.1 indicates a critical vulnerability. The attack vector (AV:N) is network-based, requiring low complexity (AC:L) and no privileges (PR:N) or user interaction (UI:N). The impact on confidentiality and integrity is high (C:H/I:H), while availability is not affected (A:N).

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

1. Header Spoofing: An attacker can spoof headers to manipulate the local/non-local network determination, allowing unauthorized access.
2. Reverse Proxy Interoperation: By exploiting the interoperation with reverse proxy servers, an attacker can bypass authentication mechanisms.

Exploitation Methods:

1. Password Bypass: Spoofing headers to trick the server into thinking the request is coming from a local network, thereby bypassing password authentication.
2. User Enumeration: Viewing a list of user accounts, which may include accounts with no password configured, allowing further exploitation.

3. Affected Systems and Software Versions

Affected Systems:

• Emby Server systems that are publicly accessible.
• Systems where the administrator has not tightened the account login configuration for administrative users.

Affected Software Versions:

• Emby Server versions prior to 4.7.12.
• Emby Server Beta versions prior to 4.8.31.

4. Recommended Mitigation Strategies

1. Update Software: Immediately update to Emby Server version 4.7.12 or Emby Server Beta version 4.8.31, which include the patch for this vulnerability.
2. Tighten Account Login Configuration: Ensure that all administrative user accounts have strong, unique passwords and that account login configurations are secure.
3. Network Segmentation: Limit public access to the Emby Server by implementing network segmentation and firewall rules.
4. Monitoring and Logging: Enable comprehensive logging and monitoring to detect and respond to any suspicious activities.
5. Regular Security Audits: Conduct regular security audits and vulnerability assessments to identify and mitigate potential security risks.

5. Impact on European Cybersecurity Landscape

The vulnerability poses a significant risk to European users of Emby Server, particularly those with publicly accessible servers. Given the widespread use of Emby Server for home media management, the potential for unauthorized access and data breaches is high. This underscores the importance of timely patching and robust security practices to protect personal and sensitive data.

6. Technical Details for Security Professionals

Vulnerability Details:

• CVE ID: CVE-2023-33193
• GSD ID: GSD-2023-33193
• Assigner: GitHub_M
• EPSS Score: 1 (indicating a low likelihood of exploitation in the wild, but this should not be relied upon as a sole indicator of risk)

ENISA IDs:

• Product:
  • ID: 94d505c0-bc49-3bec-a877-81ea5b678f0d
  • Product Name: security
  • Product Version: < 4.7.12
  • ID: d0b284c2-0388-3dfb-bfda-40fde269385a
  • Product Name: security
  • Product Version: < 4.8.31
• Vendor:
  • ID: d27e11a1-9c4c-3d08-9eea-dbce184045cb
  • Vendor Name: EmbySupport

References:

• GitHub Security Advisory

Conclusion: This vulnerability highlights the importance of maintaining up-to-date software and implementing robust security configurations. Organizations and individuals using Emby Server should prioritize updating their systems and reviewing their security posture to mitigate the risks associated with this critical vulnerability.