Horizon Alert
Summary of the vulnerability and why it matters
This advisory concerns a vulnerability in Kan, a web application, that could allow unauthorized access to internal services or cloud metadata when certain configurations are not set. The issue stems from a flaw in how the application handles file attachments, enabling attackers to potentially exploit it remotely without authentication. The main concern is confirming whether your deployment of Kan is affected and understanding the potential exposure.
- Unauthenticated attackers can access internal services.
- Leadership should monitor for exposure in networked applications.
- Confirm Kan's relevance and potential impact.
Attack Path
How an attacker could exploit the issue
An unauthenticated attacker can exploit this vulnerability by sending a request to the `/api/download/attatchment` route. If the `S3_ENDPOINT` setting is not configured, the application will use user-supplied URL parameters in a network request, allowing the attacker to target internal services, localhost ports, or cloud instance metadata.
- No authentication required.
- Triggered by specially crafted URL parameters.
- Risk of reading internal network data.
Live Threat
Current exploitation, exposure, and threat context
This vulnerability could allow an unauthenticated attacker to make the affected service fetch arbitrary URLs. When improperly configured with an unset S3_ENDPOINT, this could lead to the disclosure of internal network information, access to localhost ports, or retrieval of cloud instance metadata.
- Internal network services and ports.
- Arbitrary URL fetches by the service.
- Disclosure of internal system information.
Operational Fix
Recommended remediation, mitigation, and detection steps
Platform and application owners are responsible for addressing this unauthenticated server-side request forgery. The first practical step is to identify all instances of the affected technology, determine their reachability and business criticality, and then confirm the accountable owner to plan remediation based on risk.
- Identify accountable application/platform owners.
- Verify S3_ENDPOINT configuration and external reachability.
- Plan remediation or implement compensating controls.
