CVE-2017-9557 in Easy Chat Server
Summary
by MITRE
register.ghp in EFS Software Easy Chat Server versions 2.0 to 3.1 allows remote attackers to discover passwords by sending the username parameter in conjunction with an empty password parameter, and reading the HTML source code of the response.
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Analysis
by VulDB Data Team • 11/25/2019
The vulnerability identified as CVE-2017-9557 affects EFS Software Easy Chat Server versions 2.0 through 3.1 and represents a critical information disclosure flaw in the authentication handling mechanism. This vulnerability specifically resides within the register.ghp component of the software, which processes user registration requests and authentication operations. The flaw stems from improper validation and response handling when processing registration requests that contain empty password parameters, creating a situation where sensitive credential information can be extracted through indirect means.
The technical implementation of this vulnerability exploits a design weakness in the server's response generation logic. When a remote attacker sends a registration request containing a valid username parameter paired with an empty password parameter, the server responds with HTML content that inadvertently reveals password information. This occurs because the system fails to properly sanitize or validate the response content when processing malformed registration requests, allowing the HTML source code to contain sensitive data that should remain confidential. The vulnerability operates at the application layer and requires no authentication to exploit, making it particularly dangerous as it can be leveraged by any remote attacker.
The operational impact of this vulnerability extends beyond simple credential disclosure, as it fundamentally compromises the security model of the Easy Chat Server. Attackers can systematically enumerate user accounts and extract password information without requiring legitimate credentials, effectively bypassing traditional authentication mechanisms. This vulnerability directly violates the principle of least privilege and creates a persistent security risk that can be exploited repeatedly. The exposure of password information through HTML source code means that even if passwords are stored securely on the server, the disclosure occurs at the application response level, making the information immediately accessible to any attacker who can send the specific malformed request.
From a cybersecurity framework perspective, this vulnerability maps to CWE-200 (Information Exposure) and CWE-312 (Sensitive Data Exposure) within the Common Weakness Enumeration catalog. The attack pattern aligns with ATT&CK technique T1087.001 (Account Discovery) and T1566 (Phishing) as it enables attackers to obtain credentials that can then be used for further compromise. The vulnerability also demonstrates poor input validation practices that are commonly associated with the MITRE ATT&CK framework's Application Layer attacks category. Organizations using affected versions of Easy Chat Server face significant risk of credential compromise, potential lateral movement within networks, and possible complete system takeover if the server hosts additional sensitive services.
Mitigation strategies for this vulnerability require immediate patching of affected systems to the latest available versions of EFS Software Easy Chat Server. Organizations should implement network segmentation to limit access to the vulnerable server and monitor for suspicious registration attempts that match the exploit pattern. Additionally, administrators should conduct thorough credential reviews and implement multi-factor authentication where possible to reduce the impact of credential compromise. The vulnerability highlights the importance of proper error handling and response sanitization in web applications, emphasizing the need for comprehensive security testing including security code reviews and penetration testing to identify similar flaws in other applications.