CVE-2007-6255 in Internet Explorer
Summary
by MITRE
Buffer overflow in the Microsoft HeartbeatCtl ActiveX control in HRTBEAT.OCX allows remote attackers to execute arbitrary code via the Host argument to an unspecified method.
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Analysis
by VulDB Data Team • 01/05/2025
The vulnerability identified as CVE-2007-6255 represents a critical buffer overflow flaw within the Microsoft HeartbeatCtl ActiveX control component. This vulnerability specifically affects the HRTBEAT.OCX file which is part of Microsoft's heartbeat monitoring infrastructure designed for network connectivity verification. The flaw manifests in an unspecified method of the ActiveX control where the Host argument parameter fails to properly validate input length, creating an exploitable condition that can be leveraged by remote attackers to gain arbitrary code execution privileges on affected systems. The HeartbeatCtl ActiveX control was designed to facilitate network monitoring and heartbeat verification processes but became a vector for malicious exploitation due to inadequate bounds checking mechanisms.
The technical implementation of this vulnerability stems from improper memory management within the ActiveX control's method handling. When the Host argument is passed to the vulnerable method, the control does not perform adequate boundary checks before copying the input data into a fixed-size buffer. This classic buffer overflow condition occurs because the implementation assumes a maximum buffer size without validating that the incoming Host parameter will not exceed this predetermined limit. The overflow allows attackers to overwrite adjacent memory locations including return addresses and executable code segments, enabling them to redirect program execution flow and inject malicious payload code. This type of vulnerability directly maps to CWE-121, which categorizes buffer overflow conditions where insufficient bounds checking allows memory corruption. The attack vector operates entirely through remote exploitation since the ActiveX control is designed to be loaded and executed within web browsers or other applications that support ActiveX components.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with complete system compromise capabilities. Once successfully exploited, attackers can gain full control over the affected system, potentially leading to data exfiltration, privilege escalation, or use of the compromised machine as a pivot point for further network infiltration. The vulnerability affects systems running vulnerable versions of Microsoft Windows operating systems where the HeartbeatCtl ActiveX control is installed, particularly those that automatically load ActiveX controls from web pages or network locations. The attack surface is broadened by the fact that ActiveX controls are commonly enabled in Internet Explorer configurations, making exploitation relatively straightforward for threat actors. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1059.007 for command and control communication and T1203 for exploitation for execution, as it provides a mechanism for attackers to establish persistent access and execute malicious commands on target systems.
Mitigation strategies for CVE-2007-6255 require a multi-layered approach addressing both immediate remediation and long-term security posture improvements. The primary solution involves patching affected systems with Microsoft security updates that correct the buffer overflow condition in the HeartbeatCtl ActiveX control. Organizations should also implement ActiveX control restrictions through group policy settings that prevent automatic loading of potentially vulnerable ActiveX components from untrusted sources. Browser security configurations should be adjusted to disable ActiveX controls entirely or limit their functionality to trusted domains only. Network-level mitigations include implementing web application firewalls that can detect and block malicious ActiveX control requests, as well as monitoring for unusual network traffic patterns that may indicate exploitation attempts. Security teams should also conduct comprehensive vulnerability assessments to identify other potentially vulnerable ActiveX controls and ensure proper input validation mechanisms are implemented across all software components. The vulnerability highlights the importance of secure coding practices, particularly around memory management and input validation, which should be enforced through security development lifecycle processes to prevent similar issues in future software releases.