Attack Chain

1. An attacker sends a crafted HTTP request to one of the vulnerable Adobe Commerce REST endpoints, such as /rest/V1/guest-carts/{id}/estimate-shipping-methods.
2. The HTTP request contains a malicious XML payload designed to exploit the XXE vulnerability (CVE-2024-34102).
3. The Adobe Commerce application processes the XML payload without proper sanitization of external entity references.
4. The application attempts to resolve the external entity, leading to either local file read, or SSRF.
5. If the attacker leverages local file read, sensitive files such as app/etc/env.php (containing database credentials and encryption keys) or /etc/passwd (for user enumeration) are targeted.
6. If the attacker leverages SSRF, they can interact with internal services or external websites on behalf of the server.
7. Successful exploitation allows the attacker to extract sensitive information, potentially leading to further compromise.
8. In some scenarios, the attacker may be able to leverage the XXE vulnerability to achieve Remote Code Execution (RCE) by chaining it with other vulnerabilities or misconfigurations.

Impact

Successful exploitation of CVE-2024-34102 can lead to sensitive information disclosure, including database credentials, encryption keys, and system user information. The vulnerability can also be leveraged for Server-Side Request Forgery (SSRF), allowing attackers to interact with internal services. In certain scenarios, Remote Code Execution (RCE) may be possible, potentially allowing complete control over the affected Adobe Commerce instance. The impact is high, with a CVSS score of 9.8, and affects multiple versions of Adobe Commerce.

Recommendation

• Apply the security patches provided by Adobe to address CVE-2024-34102 on all Adobe Commerce instances.
• Deploy the Sigma rule Detect Adobe Commerce XXE via Guest Cart Endpoint to your SIEM and tune for your environment.
• Monitor web server logs for suspicious requests to the identified REST endpoints (/rest/V1/guest-carts/{id}/estimate-shipping-methods, /rest/all/V1/guest-carts/{id}/estimate-shipping-methods, /rest/V1/guest-carts/{id}/billing-address, /rest/V1/orders, /rest/V1/order) to detect potential exploitation attempts.