Microsoft IE Use-After-Free Remote Code Execution
Actively exploited in the wild. Patch or mitigate immediately — don't wait for a maintenance window.
An unauthenticated attacker, remotely over the network, with no user interaction, can fully compromise the system — steal data, tamper with it and take it offline.
Use-after-free vulnerability in Microsoft Internet Explorer 6 through 11 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via vectors related to the CMarkup::IsConnectedToPrimaryMarkup function, as exploited in the wild in April 2014. NOTE: this issue originally emphasized VGX.DLL, but Microsoft clarified that "VGX.DLL does not contain the vulnerable code leveraged in this exploit. Disabling VGX.DLL is an exploit-specific workaround that provides an immediate, effective workaround to help block known attacks."
Inferred from the weakness type (CWE) and how the flaw is reached — the techniques an attacker would chain to exploit this. Real-world corroboration appears here as threat intel is folded in.
Corroborated threat activity referencing this CVE — with source and confidence, not inference.
Named threat actors and observed ATT&CK techniques appear here as intel feeds are folded in — the ATT&CK chain above stays inferred until then.
Generated by Wavense from the CVE record — an immediate mitigation and the permanent fix.
As an immediate interim measure, disable VGX.DLL via Group Policy or local settings to block known exploit vectors, as this was an effective exploit-specific workaround. Organizations should also consider using an alternative web browser for general internet browsing to reduce exposure to IE-specific vulnerabilities. Enhance network monitoring to detect unusual outbound connections from IE processes and deploy endpoint detection and response (EDR) solutions to identify exploit attempts.
The permanent resolution requires applying the security update provided by Microsoft in bulletin MS14-021. This patch specifically addresses the use-after-free vulnerability in Internet Explorer versions 6 through 11, including the underlying issue in the CMarkup::IsConnectedToPrimaryMarkup function. Ensure all affected systems are updated to the latest available security patch to fully remediate this critical flaw.
Attackers can achieve arbitrary code execution remotely on vulnerable systems, potentially leading to full system compromise, data exfiltration, or further network penetration. Successful exploitation grants complete control over the affected system, enabling the attacker to install malware, steal sensitive information, or disrupt operations. This critical vulnerability could also be exploited to cause a denial of service through memory corruption, impacting system availability and stability.
Other CVEs affecting internet explorer
Use-after-free vulnerability in Adobe Flash Player before 13.0.0.269 and 14.x through 16.x before 16.0.0.305 on Windows and OS X and before 11.2.202.442 on Linux allows remote attackers to execute arbitrary code via unspecified vectors, as exploited in the wild in February 2015, a different vulnerability than CVE-2015-0315, CVE-2015-0320, and CVE-2015-0322.
Unspecified vulnerability in Adobe Flash Player through 13.0.0.262 and 14.x, 15.x, and 16.x through 16.0.0.287 on Windows and OS X and through 11.2.202.438 on Linux allows remote attackers to execute arbitrary code via unknown vectors, as exploited in the wild in January 2015.
Internet Explorer Memory Corruption Vulnerability
A remote code execution vulnerability exists in the way that the MSHTML engine inproperly validates input, aka "MSHTML Engine Remote Code Execution Vulnerability." This affects Microsoft Office, Microsoft Office Word Viewer, Internet Explorer 9, Internet Explorer 11, Microsoft Excel Viewer, Internet Explorer 10, Office 365 ProPlus.
A remote code execution vulnerability exists when Internet Explorer improperly accesses objects in memory, aka "Internet Explorer Memory Corruption Vulnerability." This CVE ID is unique from CVE-2017-0226.
An elevation of privilege vulnerability exists when Internet Explorer does not properly enforce cross-domain policies, which could allow an attacker to access information from one domain and inject it into another domain, aka "Internet Explorer Elevation of Privilege Vulnerability."
Microsoft Internet Explorer 9 through 11 allow remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted web site, aka "Internet Explorer Memory Corruption Vulnerability." This vulnerability is different from those described in CVE-2017-0018 and CVE-2017-0037.