CVE-2007-4607 in Easymail Objects
Summary
by MITRE
Buffer overflow in the EasyMailSMTPObj ActiveX control in emsmtp.dll 6.0.1 in the Quiksoft EasyMail SMTP Object, as used in Postcast Server Pro 3.0.61, allows remote attackers to execute arbitrary code via a long argument to the SubmitToExpress method, a different vulnerability than CVE-2007-1029.
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Analysis
by VulDB Data Team • 06/07/2025
The vulnerability described in CVE-2007-4607 represents a critical buffer overflow flaw within the EasyMailSMTPObj ActiveX control, specifically in the emsmtp.dll component version 6.0.1. This vulnerability exists within the Quiksoft EasyMail SMTP Object implementation that is integrated into Postcast Server Pro 3.0.61, creating a significant security risk for systems that utilize this software stack. The flaw manifests when a remote attacker provides an excessively long argument to the SubmitToExpress method, which is a core function of the ActiveX control designed for email submission processes. This particular vulnerability is distinct from CVE-2007-1029, indicating that multiple buffer overflow issues exist within the same software component, highlighting the severity of the underlying code quality problems.
The technical implementation of this buffer overflow occurs at the memory management level where the SubmitToExpress method fails to properly validate input length before copying data into fixed-size buffers. When an attacker supplies a maliciously crafted argument that exceeds the predetermined buffer limits, the excess data overflows into adjacent memory locations, potentially corrupting program execution flow. This type of vulnerability falls under CWE-121, which specifically addresses stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The ActiveX control's failure to implement proper input sanitization creates an exploitable condition that can be leveraged for arbitrary code execution.
The operational impact of this vulnerability extends beyond simple system compromise, as it provides attackers with a pathway to execute malicious code with the privileges of the affected application. Since ActiveX controls typically run with the security context of the user who is running the application, successful exploitation could lead to complete system compromise, data exfiltration, or establishment of persistent backdoors. The vulnerability is particularly concerning in server environments where Postcast Server Pro is deployed, as these systems often handle sensitive email communications and may be targeted by attackers seeking to exploit the server for spam distribution or as part of broader attack campaigns. The attack surface is further expanded because ActiveX controls are commonly used in web applications, making this vulnerability accessible through browser-based attacks.
Mitigation strategies for CVE-2007-4607 should prioritize immediate remediation through software updates and patches provided by Quiksoft, as the vulnerability affects a specific version of the EasyMail SMTP Object. Organizations should implement network segmentation and access controls to limit exposure of systems running this software, while also considering the complete removal of ActiveX controls from web applications where possible. Security monitoring should be enhanced to detect anomalous behavior patterns that might indicate exploitation attempts, and system administrators should conduct thorough vulnerability assessments to identify all instances of the affected software within their infrastructure. From a defensive perspective, this vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation would likely involve execution of malicious payloads through the compromised SMTP object. The vulnerability demonstrates the persistent risks associated with legacy ActiveX controls in modern security environments and underscores the importance of maintaining up-to-date software components to prevent exploitation of known buffer overflow vulnerabilities.