Authorization Bypass in OpenCTI Platform

Compliance Impact

The vulnerability in OpenCTI allows authenticated users with certain permissions to bypass Confidence Level validation and Object Marking restrictions, enabling them to downgrade confidence levels and remove security markings such as TLP:RED from sensitive threat intelligence data.

This manipulation of security markings and confidence levels could potentially lead to inaccurate or misleading threat intelligence data being used in security operations, which may impact an organization's ability to properly protect sensitive information.

While the provided information does not explicitly mention compliance with standards like GDPR or HIPAA, the ability to alter security markings and confidence levels could undermine data integrity and confidentiality controls that are critical for meeting such regulatory requirements.

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Executive Summary

This vulnerability exists in OpenCTI, an open source platform for managing cyber threat intelligence. Before version 7.260326.0, an authorization bypass flaw allowed any authenticated user with the KNOWLEDGE_KNUPDATE permission to bypass Confidence Level validation and Object Marking restrictions.

Attackers could exploit this by injecting the HTTP header 'synchronized-upsert: true', which enabled them to downgrade confidence levels, remove security markings such as TLP:RED, manipulate relationships, and affect various STIX object types including Indicators, ThreatActors, Malware, and Reports.

This issue was fixed in OpenCTI version 7.260326.0.

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Impact Analysis

The vulnerability can allow an attacker with certain permissions to bypass security controls within OpenCTI, leading to unauthorized modification of threat intelligence data.

• Downgrade confidence levels of threat intelligence, potentially misleading decision-making.
• Remove critical security markings such as TLP:RED, which are used to control information sharing and sensitivity.
• Manipulate relationships and data within STIX object types like Indicators, ThreatActors, Malware, and Reports, compromising the integrity of the threat intelligence.

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Mitigation Strategies

To mitigate this vulnerability, you should upgrade OpenCTI to version 7.260326.0 or later, where the authorization bypass issue has been fixed.

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Detection Guidance

This vulnerability involves an authorization bypass in OpenCTI where an authenticated user with KNOWLEDGE_KNUPDATE permission can inject the HTTP header `synchronized-upsert: true` to bypass Confidence Level validation and Object Marking restrictions.

To detect exploitation attempts on your network or system, you can monitor HTTP requests to the OpenCTI platform for the presence of the `synchronized-upsert: true` header, especially from users who should not have bypass permissions.

Suggested commands include using network traffic inspection tools like tcpdump or tshark to filter HTTP headers, for example:

• tcpdump -A -s 0 'tcp port 80 or tcp port 443' | grep 'synchronized-upsert: true'
• tshark -Y 'http.header contains "synchronized-upsert: true"' -T fields -e ip.src -e http.host -e http.request.uri

Additionally, reviewing OpenCTI application logs for requests containing this header or unusual modifications to confidence levels and object markings can help identify potential exploitation.

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