CVE-2012-0243 in WebAccess
Summary
by MITRE
Buffer overflow in an ActiveX control in bwocxrun.ocx in Advantech/BroadWin WebAccess before 7.0 allows remote attackers to execute arbitrary code by leveraging the ability to write arbitrary content to any pathname.
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Analysis
by VulDB Data Team • 04/10/2017
The vulnerability identified as CVE-2012-0243 represents a critical buffer overflow flaw within the ActiveX control component bwocxrun.ocx found in Advantech/BroadWin WebAccess software versions prior to 7.0. This vulnerability exists in the manner in which the ActiveX control handles memory allocation and data processing, creating an exploitable condition that can be leveraged by remote attackers to gain unauthorized system access. The flaw specifically manifests when the control processes user-supplied data without proper bounds checking, allowing attackers to overflow the allocated buffer space and potentially overwrite adjacent memory locations.
The technical implementation of this vulnerability stems from inadequate input validation within the ActiveX control's memory management routines. When the bwocxrun.ocx component receives data through its exposed interfaces, it fails to properly validate the length of incoming data before copying it into fixed-size buffers. This classic buffer overflow condition occurs because the control does not enforce strict bounds checking on the data being written to memory locations, creating opportunities for attackers to inject malicious code into memory segments adjacent to the vulnerable buffer. The vulnerability is particularly dangerous because it can be triggered through web-based attacks where malicious content is delivered via web browsers that have the vulnerable ActiveX control installed.
The operational impact of CVE-2012-0243 extends beyond simple code execution, as it provides attackers with the capability to perform arbitrary code execution on systems running vulnerable versions of Advantech/BroadWin WebAccess. This allows threat actors to gain full control over affected systems, potentially leading to data breaches, system compromise, and unauthorized access to industrial control systems. The vulnerability's remote exploitability means that attackers do not need physical access to target systems, making it particularly dangerous in industrial environments where operational technology systems are often connected to corporate networks. The ability to write arbitrary content to any pathname within the system's file structure further amplifies the attack surface, as it allows for complete system compromise through various attack vectors including web-based delivery methods.
Security professionals should note that this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and demonstrates characteristics consistent with ATT&CK technique T1059.007 for command and scripting interpreter. Organizations utilizing Advantech/BroadWin WebAccess should immediately implement mitigations including updating to version 7.0 or later, which contains the necessary patches to address the buffer overflow vulnerability. Additionally, administrators should consider implementing browser security measures such as disabling ActiveX controls in web browsers, using application whitelisting, and deploying network-based intrusion detection systems to monitor for exploitation attempts. The vulnerability also underscores the importance of proper input validation and memory management practices in software development, particularly for components that interact with untrusted data sources.
The remediation approach for this vulnerability requires comprehensive system updates and security hardening measures. Organizations should prioritize patching all instances of Advantech/BroadWin WebAccess software to version 7.0 or higher, which includes fixes for the buffer overflow conditions in the bwocxrun.ocx ActiveX control. System administrators should also implement network segmentation to limit access to industrial control systems, disable unnecessary ActiveX controls in web browsers, and establish monitoring procedures to detect potential exploitation attempts. The vulnerability serves as a reminder of the critical importance of maintaining current security patches for industrial control systems and the potential consequences of running outdated software in operational technology environments where security is paramount.