CVE-2019-11233 in BiYan
Summary
by MITRE
EXCELLENT INFOTEK BiYan v1.57 ~ v2.8 allows an attacker to leak user information without being authenticated, by sending a LOGIN_ID element to the auth/main/asp/check_user_login_info.aspx URI, and then reading the response, as demonstrated by the KW_EMAIL or KW_TEL field.
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Analysis
by VulDB Data Team • 10/06/2023
The vulnerability CVE-2019-11233 affects EXCELLENT INFOTEK BiYan versions 1.57 through 2.8, representing a critical information disclosure flaw that undermines the system's authentication security model. This vulnerability enables unauthenticated attackers to extract sensitive user information through a carefully crafted request to the authentication endpoint, specifically targeting the auth/main/asp/check_user_login_info.aspx URI. The flaw demonstrates a fundamental breakdown in access control mechanisms where the system fails to properly validate user credentials before exposing user data, creating a pathway for attackers to bypass authentication entirely.
The technical implementation of this vulnerability exploits the system's insufficient input validation and access control checks within the user authentication flow. Attackers can send a LOGIN_ID element to the designated URI and subsequently parse the response to extract sensitive information fields such as KW_EMAIL or KW_TEL, which contain user contact details. This represents a classic case of insecure direct object reference vulnerability where the system's response handling does not properly verify the requester's authorization status before returning user-specific data. The vulnerability aligns with CWE-200, which specifically addresses improper exposure of sensitive information, and demonstrates how weak authentication controls can lead to unauthorized data access.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with valuable user contact information that can be leveraged for social engineering attacks, credential stuffing attempts, or further exploitation within the target environment. The lack of authentication requirements means that any attacker with network access can repeatedly query the endpoint to harvest multiple user records, potentially enabling large-scale data collection for malicious purposes. This vulnerability particularly affects organizations relying on the BiYan system for user management, as it creates a persistent threat vector that remains active until the underlying authentication flaw is addressed.
Organizations should implement immediate mitigations including strengthening authentication requirements for all user information endpoints, implementing proper access control checks, and adding rate limiting to prevent automated harvesting of user data. The vulnerability should be addressed through patching the affected software versions or implementing compensating controls such as network segmentation and monitoring of suspicious authentication endpoint access patterns. From an ATT&CK framework perspective, this vulnerability maps to T1087.001 (Account Discovery) and T1566 (Phishing) as attackers can use the leaked information for further targeting. Additionally, implementing proper input validation and output encoding, as recommended by OWASP Top Ten, would prevent similar vulnerabilities in future deployments.