Full Report
View CSAF 1. EXECUTIVE SUMMARY CVSS v4 9.2 ATTENTION: Exploitable remotely/low attack complexity Vendor: Orthanc Equipment: Orthanc Server Vulnerability: Missing Authentication for Critical Function 2. RISK EVALUATION Successful exploitation of this vulnerability could allow an attacker to disclose sensitive information, modify records, or cause a denial-of-service condition. 3. TECHNICAL DETAILS 3.1 AFFECTED PRODUCTS The following Orthanc products are affected: Orthanc server: Versions prior to 1.5.8 3.2 VULNERABILITY OVERVIEW 3.2.1 MISSING AUTHENTICATION FOR CRITICAL FUNCTION CWE-306 Orthanc server prior to version 1.5.8 does not enable basic authentication by default when remote access is enabled. This could result in unauthorized access by an attacker. CVE-2025-0896 has been assigned to this vulnerability. A CVSS v3.1 base score of 9.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H). A CVSS v4 score has also been calculated for CVE-2025-0896. A base score of 9.2 has been calculated; the CVSS vector string is (AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N). 3.3 BACKGROUND CRITICAL INFRASTRUCTURE SECTORS: Healthcare and Public Health COUNTRIES/AREAS DEPLOYED: Worldwide COMPANY HEADQUARTERS LOCATION: Belgium 3.4 RESEARCHER Amitay Dan reported this vulnerability to Orthanc.Souvik Kandar reported this vulnerability to CISA. 4. MITIGATIONS Orthanc recommends that users update to the latest version or enable the HTTP authentication by setting the configuration "AuthenticationEnabled": true in the configuration file. CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability, such as: Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the internet. Locate control system networks and remote devices behind firewalls and isolating them from business networks. When remote access is required, utilize more secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have their own vulnerabilities and should be updated to the most current version available. Also recognize VPNs are only as secure as the connected devices. CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures. CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov/ics. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies. CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets. Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies. Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents. CISA also recommends users take the following measures to protect themselves from social engineering attacks: Do not click web links or open attachments in unsolicited email messages. Refer to Recognizing and Avoiding Email Scams for more information on avoiding email scams. Refer to Avoiding Social Engineering and Phishing Attacks for more information on social engineering attacks. No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time. 5. UPDATE HISTORY February 6, 2025: Initial Publication
Analysis Summary
# Vulnerability: Orthanc Server Remote Authentication Bypass
## CVE Details
- CVE ID: CVE-2025-0896
- CVSS Score: 9.8 (CVSS v3.1) / 9.2 (CVSS v4.0) (Critical)
- CWE: Missing Authentication for Critical Function
## Affected Systems
- Products: Orthanc server
- Versions: Prior to 1.5.8
- Configurations: When remote access is enabled without explicit configuration changes from default settings.
## Vulnerability Description
The Orthanc server versions prior to 1.5.8 fail to enable basic HTTP authentication by default even when remote access is configured. This critical flaw allows an unauthenticated remote attacker to access sensitive functions, leading to potential disclosure of sensitive information, modification of records, or a denial-of-service condition.
## Exploitation
- Status: No known public exploitation targeting this specific vulnerability has been reported to CISA at this time.
- Complexity: Low (Indicated by CVSS vectors AV:N/AC:L)
- Attack Vector: Network
## Impact
- Confidentiality: High
- Integrity: High
- Availability: High
## Remediation
### Patches
- Upgrade Orthanc server to version **1.5.8 or later**.
### Workarounds
1. **Enable HTTP Authentication Manually:** Set the configuration option `"AuthenticationEnabled": true` in the server's configuration file.
2. **Network Isolation (CISA Recommended):**
* Minimize network exposure for the Orthanc device.
* Ensure the device is not accessible directly from the internet.
* Place the system behind firewalls and isolate it from business networks.
* If remote access is necessary, utilize secure methods such as patched Virtual Private Networks (VPNs).
## Detection
- **Indicators of Compromise:** Look for successful access requests to the Orthanc API endpoints without corresponding authentication headers, especially if the system was presumed to be configured securely.
- **Detection Methods and Tools:** Monitor network traffic for unauthenticated HTTP requests targeting the Orthanc service. Review system logs for unusual activity or function calls executed without credentials.
## References
- Vendor Advisory: https://www.orthanc-server.com/download.php
- CISA Alert: https://github.com/cisagov/CSAF (View CSAF file)
- CVSS v3.1 Vector: AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CVSS v4.0 Vector: AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N