Introduction

ownCloud, a prominent open-source file-sharing software company, recently unveiled three critical vulnerabilities, with the most severe risking sensitive data exposure. This article delves into the specifics of these vulnerabilities, their potential impact, and the recommended actions for users to secure their installations promptly.

CVE-2023-49103: Sensitive Data Exposure

At the forefront is CVE-2023-49103, a vulnerability with a maximum severity rating of 10. This flaw affects the Garaphapi app versions 0.2.0 to 0.3.0 and, when exploited, could reveal admin passwords, mail server credentials, and license keys in containerized deployments. The issue stems from a third-party library providing a revealing URL in the PHP environment’s configuration details.

Mitigation Steps for CVE-2023-49103

To address this vulnerability, users are urged to delete a specific file in the ownCloud directory and, as a precaution, change sensitive credentials. Even if not using containers, ownCloud recommends implementing these fixes, underlining the broader risk of exposed configuration details.

ownCloud’s Response and Future Measures

In response, ownCloud swiftly disabled the phpinfo function in Docker containers and pledged further hardenings in upcoming core releases. This proactive approach demonstrates the company’s commitment to fortifying its software against similar vulnerabilities.

CVE-2023-49105: Authentication Bypass

The second critical vulnerability, CVE-2023-49105, poses an authentication bypass threat with a near-maximum severity rating of 9.8. Attackers, armed with the knowledge of a target’s username and the absence of a signing-key configuration (default in ownCloud), can gain unauthorized access to, modify, or delete any file.

Mitigation Steps for CVE-2023-49105

#CyberAlert | ownCloud Vulnerability

The Cyber Centre is aware of three recent critical vulnerabilities impacting ownCloud, an open-source file sync and sharing solution used to manage and share files hosted on-site.  
https://t.co/Y0GjwzUi8z

🧵⤵️ pic.twitter.com/PM0dlqLUDs

— Canadian Centre for Cyber Security (@cybercentre_ca) November 28, 2023

Users are advised to deny using pre-signed URLs in scenarios where no signing key is configured, mitigating the exploitation of this authentication bypass flaw within core versions 10.6.0 to 10.13.0.

CVE-2023-49107: Subdomain Validation Bypass

The final vulnerability, CVE-2023-49107, initially categorized as “critical” by ownCloud, involves a subdomain validation bypass issue affecting oauth2 library versions before 0.6.1. The National Vulnerability Database slightly reduces its severity score.

Patch and Workaround for CVE-2023-49107

ownCloud’s patch involves strengthening the validation code in the oauth2 app, with users also having the option to disable the “Allow Subdomains” feature as an additional workaround.

ownCloud’s User Base and Importance

Despite these vulnerabilities, ownCloud serves over 600 enterprise customers and over 200 million users across diverse sectors. From IT to government, and healthcare education, ownCloud’s extensive list of high-profile customers showcases its widespread adoption.

Conclusion

In conclusion, the disclosed vulnerabilities highlight the importance of promptly addressing security issues. Users are encouraged to apply the recommended fixes and stay vigilant. ownCloud’s commitment to ongoing security enhancements reinforces its dedication to providing a secure file-sharing environment.

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