SAP HANA User Enumeration via Request Manipulation

Executive Summary

CVE-2026-44753 is a vulnerability in SAP HANA Database, specifically in the user self-service tools. It allows an unauthenticated user to send specially crafted requests to the system.

These requests produce distinguishable responses, which can be used to enumerate valid user accounts and email addresses. This means an attacker can identify which user accounts or email addresses exist in the system without needing authentication.

The vulnerability has a low impact on confidentiality because it only allows enumeration of user accounts and does not compromise data integrity or system availability.

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Detection Guidance

Detection of this vulnerability involves identifying distinguishable responses from SAP HANA Database user self-service tools when specially crafted requests are sent. This can indicate the presence of user enumeration via timing or error message differences.

• Use network scanning tools like Burp Suite, OWASP ZAP, or custom scripts to send requests to the SAP HANA user self-service endpoints and analyze responses for inconsistencies (e.g., different error messages or response times for valid vs. invalid users).
• Check SAP HANA logs for repeated failed authentication attempts or unusual access patterns to user self-service tools, which may indicate enumeration attempts.
• Review SAP HANA configuration settings to ensure user enumeration protections (e.g., uniform error messages, rate limiting) are enabled. Refer to SAP Security Note 3732522 for specific guidance.

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Impact Analysis

This vulnerability can impact you in the following ways:

• An attacker could enumerate valid user accounts or email addresses in your SAP HANA Database. This information could be used for targeted phishing attacks or social engineering campaigns.
• While the vulnerability does not directly compromise data integrity or system availability, the exposure of user account details could serve as a starting point for further attacks, such as brute-force or credential-stuffing attempts.
• If your organization relies on SAP HANA for sensitive operations, the enumeration of user accounts could pose a risk to confidentiality, especially if those accounts have access to critical or regulated data.

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Compliance Impact

This vulnerability may affect compliance with common standards and regulations in the following ways:

• GDPR: Under GDPR, organizations must protect personal data from unauthorized access. The enumeration of user accounts or email addresses could be considered a breach of confidentiality, especially if those accounts are linked to personal data. This may require reporting to authorities if the exposure is deemed a risk to individuals' rights and freedoms.
• HIPAA: For organizations handling protected health information (PHI), HIPAA requires safeguards to prevent unauthorized access to sensitive data. If the enumerated user accounts have access to PHI, this vulnerability could be seen as a failure to implement adequate access controls, potentially leading to non-compliance.
• Other standards: Many compliance frameworks, such as ISO 27001 or NIST, require organizations to protect against unauthorized disclosure of information. The ability to enumerate user accounts could be viewed as a failure to meet these requirements, depending on the context and scope of the vulnerability.

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Mitigation Strategies

To mitigate this vulnerability, apply the following steps to reduce the risk of user enumeration in SAP HANA Database user self-service tools.

• Apply the latest SAP security patches or updates, particularly those addressing user enumeration in self-service tools. Refer to SAP Security Note 3732522 for specific patch details.
• Configure SAP HANA to return uniform error messages for failed authentication attempts, regardless of whether the user exists or not, to prevent distinguishable responses.
• Implement rate limiting or account lockout mechanisms to prevent brute-force or enumeration attacks targeting user self-service endpoints.
• Review and restrict access to user self-service tools to trusted networks or IP ranges to minimize exposure to unauthenticated attackers.
• Monitor SAP HANA logs for suspicious activity, such as repeated failed login attempts, and set up alerts for potential enumeration attacks.

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