CVE-2017-6416 in SysGauge
Summary
by MITRE
An issue was discovered in SysGauge 1.5.18. A buffer overflow vulnerability in SMTP connection verification leads to arbitrary 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 • 09/04/2020
The vulnerability identified as CVE-2017-6416 represents a critical buffer overflow flaw within SysGauge version 1.5.18 that specifically targets the SMTP connection verification process. This issue resides in the application's handling of SMTP server responses, particularly when processing the initial 220 response code that indicates a service is ready for communication. The flaw manifests when the application receives an unusually long response string from a malicious SMTP daemon, which exceeds the allocated buffer space. This buffer overflow condition creates a potential pathway for remote code execution, allowing attackers to compromise systems running the vulnerable software. The vulnerability directly maps to CWE-121 Stack-based Buffer Overflow, a well-documented weakness that occurs when data is copied into a stack buffer without proper bounds checking, leading to memory corruption. The attack requires minimal user interaction as the vulnerability is triggered during automated SMTP connection verification processes, making it particularly dangerous in environments where email monitoring is critical.
The technical exploitation of this vulnerability occurs through a carefully crafted SMTP daemon that deliberately sends an oversized 220 response string to the SysGauge application. When the application attempts to process this malformed response, it fails to validate the string length against the allocated buffer capacity, causing data to overflow into adjacent memory regions. This memory corruption can overwrite critical program execution data including return addresses, function pointers, or other control structures necessary for proper program operation. Attackers can leverage this overflow to inject and execute malicious code within the application's execution context, potentially gaining full system control. The vulnerability's impact is amplified by the fact that SMTP verification is a routine operation in many monitoring and management applications, making the attack surface broad and the exploitation likelihood high. This type of vulnerability falls under the ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1068 for Exploitation for Privilege Escalation, as successful exploitation could lead to elevated system privileges.
The operational impact of CVE-2017-6416 extends beyond simple system compromise, as it affects the integrity and availability of monitoring infrastructure that relies on SysGauge for system health assessment. Organizations using this software may experience unauthorized access to their network monitoring systems, potentially allowing attackers to manipulate or disable security monitoring capabilities. The vulnerability creates a persistent threat vector that could be exploited repeatedly, as the buffer overflow condition remains present until the software is patched or updated. Network administrators who depend on SysGauge for email-based alerts and notifications face significant risk, as attackers could potentially interfere with critical alerting mechanisms or use the compromised system as a pivot point for further network exploration. The vulnerability also impacts the application's stability, potentially causing unexpected crashes or system instability during normal operation when encountering malicious SMTP responses. This makes the flaw particularly dangerous in production environments where system reliability and continuous monitoring are essential.
Mitigation strategies for CVE-2017-6416 should prioritize immediate software updates from the vendor, as this vulnerability was addressed through proper input validation and buffer size enforcement in subsequent releases. Organizations should implement network-level controls to monitor and filter SMTP traffic, particularly when dealing with external email servers, to prevent malicious responses from reaching the vulnerable application. The implementation of input validation measures within the application's SMTP handling code is crucial, including length checking for response strings and proper buffer management techniques. Security teams should conduct thorough vulnerability assessments of all monitoring systems to identify similar buffer overflow vulnerabilities in other applications that handle network protocol responses. Additionally, network segmentation and access controls should be implemented to limit the potential impact of exploitation, ensuring that compromised monitoring systems cannot be used as entry points for broader network attacks. System hardening practices including disabling unnecessary SMTP functionality and implementing proper memory protection mechanisms such as stack canaries or address space layout randomization should be considered as additional protective measures against similar vulnerabilities.