CVE-2019-19168 in Dext5.ocx ActiveX
Summary
by MITRE
Dext5.ocx ActiveX 5.0.0.116 and eariler versions contain a vulnerability, which could allow remote attacker to download and execute remote arbitrary file by setting the arguments to the activex method. This can be leveraged for code execution.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 10/15/2020
The vulnerability identified as CVE-2019-19168 affects Dext5.ocx ActiveX control version 5.0.0.116 and earlier, representing a critical security flaw that enables remote code execution through improper input validation within the ActiveX component. This vulnerability resides in the control's method argument handling mechanism, where attacker-controlled input is not properly sanitized before being processed. The issue manifests when malicious actors exploit the ActiveX control's interface to manipulate method parameters, creating conditions that allow arbitrary file download and execution capabilities. The vulnerability's severity stems from the inherent trust model of ActiveX controls within Windows environments, where controls are executed with the privileges of the user who initiated the application. This allows attackers to bypass standard security boundaries and execute malicious code directly on target systems.
The technical exploitation of this vulnerability follows a pattern consistent with ActiveX control abuse techniques documented in various threat intelligence reports. Attackers typically construct malicious web pages or Office documents containing crafted ActiveX method calls that leverage the vulnerable argument handling. The flaw falls under CWE-74, which describes "Improper Neutralization of Special Elements in Output Used by a Downstream Component", specifically manifesting as improper input validation in the ActiveX control's method interface. When an attacker supplies malicious arguments to the ActiveX methods, the control fails to validate these inputs properly, leading to execution of arbitrary code on the victim's system. This represents a classic buffer overflow or injection vulnerability where untrusted data flows directly into executable code paths within the ActiveX component.
The operational impact of CVE-2019-19168 extends beyond simple code execution, as it provides attackers with persistent access to compromised systems. Once exploited, the vulnerability allows threat actors to establish backdoors, escalate privileges, and perform reconnaissance activities within the victim's network. The attack surface is particularly concerning given that ActiveX controls are commonly enabled in enterprise environments, especially in legacy systems where security updates may be delayed or not implemented. The vulnerability can be leveraged for initial access through phishing campaigns targeting users who encounter malicious web content or documents containing the vulnerable ActiveX control. This attack vector aligns with ATT&CK technique T1193, "Spearphishing Attachment", where malicious attachments or web content contain the exploit for the ActiveX control vulnerability.
Mitigation strategies for CVE-2019-19168 should focus on immediate remediation through software updates, as the vendor has released patches addressing this specific vulnerability. Organizations should disable ActiveX controls in web browsers and implement strict security policies that prevent automatic execution of ActiveX components. Network-based protections such as web application firewalls can help detect and block exploitation attempts by monitoring for suspicious ActiveX method calls. Additionally, security teams should conduct comprehensive vulnerability assessments to identify all systems running affected versions of the Dext5.ocx control and ensure proper patch management procedures are in place. The remediation process should include disabling ActiveX controls in Internet Explorer and other browsers, as well as implementing application whitelisting policies that prevent execution of unsigned or untrusted ActiveX components. Organizations should also consider implementing behavioral monitoring solutions that can detect anomalous ActiveX control behavior indicative of exploitation attempts.