CVE-2023-49105
Prioritize patching. It under exploitation confirmed by CISA and has a public proof of concept.
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
An attacker can access, modify, or delete any file in ownCloud without logging in, as long as they know the victim's username and the victim hasn't set up a signing key. This is a critical flaw because it completely bypasses the authentication system.
CVE-2023-49105 exploits improper authentication validation in ownCloud's pre-signed URL mechanism; when no signing-key is configured for a user, the application incorrectly accepts pre-signed URLs without verifying the cryptographic signature. An unauthenticated attacker with knowledge of a target username can forge requests to access, modify, or delete arbitrary files, bypassing all access controls. Affected versions: 10.6.0 through 10.13.0.