CVE-2007-3536 in Netlinx Vnc Activex Control
Summary
by MITRE
Multiple buffer overflows in the AMX NetLinx VNC (AmxVnc) ActiveX control in AmxVnc.dll 1.0.13.0 allow remote attackers to execute arbitrary code via long (1) Host, (2) Password, or (3) LogFile property values.
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Analysis
by VulDB Data Team • 09/23/2024
The vulnerability identified as CVE-2007-3536 represents a critical security flaw in the AMX NetLinx VNC ActiveX control component known as AmxVnc.dll version 1.0.13.0. This issue manifests as multiple buffer overflow conditions that occur when processing property values for Host, Password, and LogFile parameters. The vulnerability exists within the ActiveX control implementation that enables remote desktop functionality through the AMX NetLinx platform, which is commonly used in commercial and industrial automation environments. The buffer overflows occur during the processing of user-supplied input data, specifically when the control attempts to handle excessively long strings in these three critical properties.
The technical nature of this vulnerability stems from improper bounds checking within the AmxVnc.dll component. When remote attackers provide overly long strings as values for the Host, Password, or LogFile properties, the control fails to validate the input length before copying the data into fixed-size memory buffers. This classic buffer overflow condition allows attackers to overwrite adjacent memory locations, potentially leading to arbitrary code execution. The vulnerability is particularly concerning because it operates within an ActiveX control context, which means it can be triggered through web browsers when visiting malicious websites that embed the vulnerable control. The attack vector is remote and does not require authentication, making it accessible to attackers without privileged access to the target system.
The operational impact of CVE-2007-3536 extends significantly beyond typical buffer overflow scenarios due to the widespread deployment of AMX NetLinx systems in commercial environments. These systems are commonly used in building automation, control systems, and industrial environments where the compromise of a single device could affect critical infrastructure operations. The vulnerability affects systems running vulnerable versions of the AMX NetLinx software, particularly those that expose the ActiveX control through web interfaces or allow untrusted web content to execute on target machines. The potential for remote code execution creates scenarios where attackers could gain full system control, install backdoors, or escalate privileges within the target environment. This vulnerability directly aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a classic example of how ActiveX controls can become attack vectors when not properly secured against input validation failures.
Mitigation strategies for this vulnerability require immediate action to address the root cause through proper input validation and memory management practices. Organizations should implement immediate patching procedures to update to versions of AmxVnc.dll that do not contain the vulnerable buffer handling code. The recommended approach includes disabling ActiveX controls in web browsers when visiting untrusted websites, implementing network segmentation to limit exposure, and conducting comprehensive vulnerability assessments of all systems running affected software. Additionally, security professionals should consider implementing application whitelisting policies to prevent execution of vulnerable ActiveX controls in enterprise environments. From an ATT&CK framework perspective, this vulnerability maps to techniques involving remote code execution through compromised software components and represents a significant threat to supply chain security. The vulnerability demonstrates how seemingly benign ActiveX controls can become critical attack vectors when input validation is insufficient, highlighting the importance of secure coding practices and regular security assessments in industrial control systems.