ownCloud Vulnerability Exploited (CVE-2023-49103)

THE THREAT

eSentire is aware of widespread exploitation attempts targeting the recently disclosed ownCloud vulnerability CVE-2023-49103. CVE-2023-49103 (CVSS: 10) is tracked as a disclosure of sensitive credentials and configuration in containerized deployments vulnerability. Exploitation would allow an unauthenticated threat actor to access admin passwords, mail server credentials, and license keys, potentially leading to the theft of sensitive information and other malicious actions.

Proof-of-Concept (PoC) exploit code is publicly available for this vulnerability, simplifying the exploitation process for threat actors. Security patches are not currently available for CVE-2023-49103. As such, it is critical that organizations apply the available mitigations to prevent exploitation.

What we’re doing about it

• The eSentire Threat Response Unit (TRU) is performing threat hunts across the eSentire client base
• IP addresses, associated with real-world attacks, are blocked via the eSentire Global Block list
• eSentire Managed Vulnerability Service (MVS) will add the relevant plugins to identify CVE-2023-49103 as they become available
• The eSentire Threat Intelligence team is actively tracking this vulnerability for additional details and detection opportunities

What you should do about it

• Organizations are recommended to follow the mitigation steps outlined in the ownCloud advisory
  • Delete the file owncloud/apps/graphapi/vendor/microsoft/microsoft-graph/tests/GetPhpInfo.php
• Additionally, it is recommended to reset the following credentials/authentication tokens:
  • ownCloud admin passwords
  • Mail server credentials
  • Database credentials
  • Object-Store/S3 access-key

Additional information

On November 21st, the open-source software company ownCloud disclosed three critical vulnerabilities. As of November 27th, active exploitation of CVE-2023-49103 was identified, with the earliest signs of exploitation traced back to November 25th.

CVE-2023-49103 impacts ownCloud’s owncloud/graphapi 0.2.x before 0.2.1 and 0.3.x before 0.3.1. The graphapi app relies on a third-party GetPhpInfo.php library that provides a URL. In an attack scenario, a threat actor could access this URL and reveal the configuration details of the PHP environment. In containerized environments, this information may include sensitive data such as the ownCloud admin password, mail server credentials, and license key. If ownCloud is not running in a containerized environment, this still poses a risk as phpinfo exposes various other potentially sensitive configuration details that could be exploited by an attacker to gather information about the system.

In addition to CVE-2023-49103, ownCloud disclosed two vulnerabilities which have not been observed being exploited at this time.

• CVE-2023-49104 (CVSS: 9.0) is a Subdomain Validation Bypass vulnerability that if exploited would allow threat actors to redirect callbacks to a TLD controlled by the attacker.
• CVE-2023-49105 (CVSS: 9.8) is a WebDAV Api Authentication Bypass vulnerability that would allow attackers to access, modify or delete files if they know the victim’s username and if the victim does not have a signing key configured, which is the default. 

References:

[1] https://owncloud.com/security-advisories/disclosure-of-sensitive-credentials-and-configuration-in-containerized-deployments/
[2] https://nvd.nist.gov/vuln/detail/CVE-2023-49103
[3] https://www.greynoise.io/blog/cve-2023-49103-owncloud-critical-vulnerability-quickly-exploited-in-the-wild
[4] https://owncloud.com/security-advisories/subdomain-validation-bypass/
[5] https://owncloud.com/security-advisories/webdav-api-authentication-bypass-using-pre-signed-urls/