CVE-2018-2379 in HANA Extended Application Services
Summary
by MITRE
In SAP HANA Extended Application Services, 1.0, an unauthenticated user could test if a given username is valid by evaluating error messages of a specific endpoint.
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Analysis
by VulDB Data Team • 01/04/2020
SAP HANA Extended Application Services version 1.0 contains a critical information disclosure vulnerability that allows unauthenticated attackers to enumerate valid usernames within the system. This vulnerability resides in the authentication and authorization mechanisms of the extended application services component, specifically through a vulnerable endpoint that provides different error responses based on whether a username exists in the system. The flaw enables attackers to perform automated username enumeration attacks without requiring any prior authentication credentials, making it particularly dangerous for systems that rely on strong user identification mechanisms.
The technical implementation of this vulnerability stems from improper error handling within the application services layer where the system returns distinct error messages for valid versus invalid usernames during authentication attempts. When an attacker submits a request to the specific vulnerable endpoint with a test username, the system responds with different error codes or message formats depending on whether the account exists in the user directory. This differential response behavior creates a side-channel information leak that can be exploited to systematically identify valid user accounts through automated testing. The vulnerability affects the core authentication flow of the extended application services and represents a classic case of insecure error handling that violates fundamental security principles.
The operational impact of this vulnerability extends beyond simple username enumeration, as it provides attackers with critical intelligence for subsequent attack phases. Once valid usernames are discovered, attackers can leverage this information for targeted password spraying, brute force attacks, or social engineering campaigns. The vulnerability affects all users of SAP HANA Extended Application Services version 1.0 regardless of their authentication status, making it particularly dangerous in environments where multiple users have access to the system. The ease of exploitation means that this vulnerability can be identified and exploited by attackers with minimal technical expertise, significantly increasing the risk to organizations using affected systems.
Organizations should immediately apply the relevant SAP security patches and updates to address this vulnerability. The recommended mitigation strategy includes implementing proper error handling that returns consistent responses regardless of whether a username exists in the system. Additionally, organizations should consider implementing account lockout mechanisms and monitoring for unusual authentication patterns that might indicate enumeration attempts. This vulnerability aligns with CWE-209, which addresses improper error message information exposure, and maps to ATT&CK technique T1078.004 for valid accounts and T1562.001 for defense evasion through consistent error handling. Network segmentation and access controls should also be reviewed to limit potential attack vectors, while security monitoring should be enhanced to detect and alert on suspicious authentication patterns that might indicate username enumeration activities.