Executive Summary

This vulnerability exists in Cronicle, a multi-server task scheduler with a web-based UI. Before version 0.9.111, child processes (jb) could include an update_event key in their JSON output. The server would apply this update directly to the parent event's stored configuration without checking for authorization.

As a result, a low-privilege user who can create and run events could modify any property of any event, including sensitive fields like webhook URLs and notification emails.

This flaw allows unauthorized modification of event configurations, which is a security risk. The issue was fixed in version 0.9.111.

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Impact Analysis

This vulnerability can allow a low-privilege user to alter event configurations without proper authorization.

• Modification of webhook URLs could redirect event notifications to unauthorized endpoints.
• Changing notification emails could result in sensitive information being sent to unintended recipients.

Such unauthorized changes could lead to information disclosure, disruption of scheduled tasks, or misuse of the system's notification mechanisms.

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Mitigation Strategies

To mitigate this vulnerability, upgrade Cronicle to version 0.9.111 or later, where the issue has been fixed.

Until the upgrade is applied, restrict low-privilege users from creating and running events to prevent unauthorized modification of event properties.

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Compliance Impact

This vulnerability allows a low-privilege user to modify event configurations, including webhook URLs and notification emails, without authorization. As a result, sensitive job data such as script contents, environment variables, and internal IP addresses can be exfiltrated to attacker-controlled endpoints.

Such unauthorized data exposure and modification can lead to violations of data protection regulations like GDPR and HIPAA, which require strict controls over access to and transmission of sensitive information.

Specifically, the ability to redirect notifications and webhooks to attacker-controlled servers could result in unauthorized disclosure of personal or protected health information, undermining compliance with confidentiality and integrity requirements mandated by these standards.

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Detection Guidance

Detection of this vulnerability involves identifying if any low-privilege user-created events are modifying event configurations via the `update_event` key in their JSON output. Since the vulnerability allows unauthorized updates to event properties such as webhook URLs and notification emails, monitoring for unexpected changes to these configurations can indicate exploitation.

You can check the Cronicle event configurations for suspicious or unauthorized modifications, especially changes to webhook URLs or notification email addresses.

Suggested commands or steps include:

• Review event configuration files or database entries for unexpected changes to webhook URLs or notification emails.
• Use grep or similar tools to search for the `update_event` key in job output logs or event definitions, for example: `grep -r 'update_event' /path/to/cronicle/jobs`.
• Audit user permissions to identify low-privilege users who have the ability to create and run events.
• Monitor network traffic for outbound connections to unexpected webhook URLs or external servers that could be receiving exfiltrated data.

Because the vulnerability involves JSON output from job child processes, inspecting logs or outputs for JSON containing the `update_event` key can help detect attempts to exploit this issue.

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