CVE-2017-6506 in Data Expert Ultimate
Summary
by MITRE
In Azure Data Expert Ultimate 2.2.16, the SMTP verification function suffers from a buffer overflow vulnerability, leading to remote code execution. The attack vector is a crafted SMTP daemon that sends a long 220 (aka "Service ready") string.
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Analysis
by VulDB Data Team • 09/05/2020
The vulnerability identified as CVE-2017-6506 resides within Azure Data Expert Ultimate version 2.2.16, a database management and analysis tool that provides comprehensive data handling capabilities. This particular flaw manifests in the application's Simple Mail Transfer Protocol verification function, which is designed to validate email server configurations and ensure proper communication channels. The buffer overflow vulnerability represents a critical security weakness that can be exploited by remote attackers to gain unauthorized control over the affected system. The specific attack vector involves crafting a malicious SMTP daemon that deliberately sends an oversized 220 response string, which is the standard SMTP greeting message indicating that the server is ready to accept commands. This particular response code serves as the initial handshake in SMTP communication protocols, making it a natural target for exploitation.
The technical implementation of this vulnerability stems from inadequate input validation within the SMTP verification component of the application. When the tool processes the SMTP 220 response, it fails to properly handle strings that exceed the allocated buffer size, leading to memory corruption that can be leveraged for arbitrary code execution. The buffer overflow occurs during the parsing of the service ready message, where the application does not perform sufficient bounds checking on the incoming data. This type of vulnerability falls under the Common Weakness Enumeration category CWE-121, which specifically addresses stack-based buffer overflow conditions. The flaw represents a classic example of insufficient boundary checking, where the application assumes that incoming SMTP responses will not exceed predetermined lengths, creating an exploitable condition that allows attackers to overwrite adjacent memory locations.
The operational impact of this vulnerability extends beyond simple remote code execution, as it provides attackers with the capability to completely compromise the target system running Azure Data Expert Ultimate. An attacker who successfully exploits this vulnerability can execute malicious code with the privileges of the affected application, potentially leading to full system compromise, data exfiltration, or establishment of persistent backdoors. The remote nature of the attack means that exploitation can occur without requiring physical access to the system, making it particularly dangerous for environments where the application might be exposed to untrusted network traffic. This vulnerability is particularly concerning because SMTP verification is a common function used during database configuration and administrative tasks, making the attack surface broader than initially apparent. The vulnerability also aligns with ATT&CK technique T1059.007, which covers the use of command and scripting interpreters for remote code execution, as the buffer overflow enables attackers to inject and execute arbitrary commands within the application's execution context.
Mitigation strategies for CVE-2017-6506 should prioritize immediate patching of the affected software version, as Microsoft and the vendor would have released security updates to address this specific buffer overflow condition. Organizations should implement network segmentation to limit exposure of the affected application to untrusted networks and consider disabling SMTP verification functionality if it is not essential for operations. Input validation measures should be enhanced to include proper bounds checking on all SMTP response data, particularly the 220 service ready message. Security monitoring should be enhanced to detect unusual SMTP traffic patterns that might indicate exploitation attempts. The vulnerability also underscores the importance of secure coding practices, particularly in the area of memory management and input validation, as highlighted by the OWASP Top Ten security risks. Regular security assessments and penetration testing should be conducted to identify similar buffer overflow conditions in other components of the application stack, as these types of vulnerabilities often occur in similar code patterns across different software systems.