Critical Information Disclosure Vulnerability in ownCloud's Graph API: CVE-2023-49103 Analysis and Mitigation

Executive Summary

CVE-2023-49103 is a critical information disclosure vulnerability in ownCloud's Graph API. With a CVSS 3.1 score of 10, this vulnerability allows unauthenticated attackers to remotely leak sensitive information via the output of the PHP function

phpinfo()

. This vulnerability is particularly concerning due to its remote exploitability and lack of authentication requirements. Immediate action is required to mitigate the risks associated with this vulnerability.

Technical Information

CVE-2023-49103 is a severe information disclosure vulnerability identified in the Graph API App of ownCloud. The vulnerability is characterized by its ability to allow an attacker to remotely trigger the

phpinfo()

function, which outputs detailed information about the server environment. This information can include configuration settings, environment variables, and other sensitive data that could be leveraged for further attacks.

The vulnerability is present in all ownCloud Server instances below version 10.13.3 and ownCloud/graphapi versions 0.2.x (before 0.2.1) and 0.3.x (before 0.3.1). The critical nature of this vulnerability is underscored by its CVSS 3.1 score of 10, indicating the highest level of severity.

The attack vector for CVE-2023-49103 is remote, meaning that an attacker can exploit the vulnerability without physical access to the target system. Furthermore, no authentication is required to exploit this vulnerability, making it an attractive target for malicious actors.

The vulnerability can be exploited by targeting a specific URI that triggers the

phpinfo()

function. This function outputs a wealth of information about the server's PHP configuration, including loaded modules, environment variables, and other sensitive data. An attacker can use this information to gain insights into the server's configuration and potentially identify other vulnerabilities or misconfigurations that could be exploited.

Exploitation in the Wild

There have been multiple reports of CVE-2023-49103 being actively exploited in the wild. Attackers are using automated tools to scan for vulnerable ownCloud instances and exploit the

phpinfo()

function to gather sensitive information. The information disclosed by this vulnerability can be used to facilitate further attacks, such as privilege escalation or lateral movement within a network.

A proof of concept (PoC) for this vulnerability is available on GitHub, demonstrating how an attacker can exploit the vulnerability to leak sensitive information. The PoC can be found here: https://github.com/creacitysec/CVE-2023-49103.

To detect potential exploitation attempts, a Sigma rule has been developed. This rule can help identify suspicious activity related to the exploitation of CVE-2023-49103. The Sigma rule is available here: https://socprime.com/blog/cve-2023-49103-detection-a-critical-vulnerability-in-ownclouds-graph-api-app-leveraged-for-in-the-wild-attacks/.

APT Groups using this vulnerability

While there are no specific APT groups currently linked to the exploitation of CVE-2023-49103, the nature of the vulnerability makes it a potential target for groups interested in gathering sensitive information for further attacks. The sectors and countries targeted by APT groups often include government agencies, financial institutions, healthcare organizations, and critical infrastructure providers.

Affected Product Versions

The following versions of ownCloud are affected by CVE-2023-49103: All ownCloud Server instances below version 10.13.3 ownCloud/graphapi versions 0.2.x (before 0.2.1) and 0.3.x (before 0.3.1)

Workaround and Mitigation

To mitigate the risks associated with CVE-2023-49103, it is recommended to: Update ownCloud: Ensure that you are running the latest version of ownCloud, as patches have been released to address this vulnerability. Restrict Access: Limit access to the Graph API App to trusted users and networks. Monitor Logs: Regularly monitor server logs for any unusual activity that may indicate an exploitation attempt.

References

For further reading and detailed analysis, please refer to the following sources: NVD CVE-2023-49103 Detail: https://nvd.nist.gov/vuln/detail/CVE-2023-49103 Rapid7 Blog on CVE-2023-49103: https://www.rapid7.com/blog/post/2023/12/01/etr-cve-2023-49103-critical-information-disclosure-in-owncloud-graph-api/ Stormshield Security Alert: https://www.stormshield.com/news/security-alert-cve-2023-49103-stormshield-products-response/ Qualys ThreatProtect: https://threatprotect.qualys.com/2023/12/06/owncloud-sensitive-information-disclosure-vulnerability-cve-2023-49103/ Ambionics Blog: https://www.ambionics.io/blog/owncloud-cve-2023-49103-cve-2023-49105 Arctic Wolf Blog: https://arcticwolf.com/resources/blog/cve-2023-49103-cve-2023-49104-and-cve-2023-49105-multiple-critical-vulnerabilities-in-owncloud/ SANS ISC Diary: https://isc.sans.edu/diary/Scans+for+ownCloud+Vulnerability+CVE202349103/30432

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