CVE-2013-3918 in Internet Explorer
Summary
by MITRE
The InformationCardSigninHelper Class ActiveX control in icardie.dll in Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, and Windows RT Gold and 8.1 allows remote attackers to execute arbitrary code or cause a denial of service (out-of-bounds write) via a crafted web page that is accessed by Internet Explorer, as exploited in the wild in November 2013, aka "InformationCardSigninHelper Vulnerability."
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Analysis
by VulDB Data Team • 04/22/2026
The CVE-2013-3918 vulnerability represents a critical out-of-bounds write flaw within the InformationCardSigninHelper ActiveX control component of Microsoft Windows operating systems. This vulnerability specifically affects multiple versions of Windows including XP SP2 and SP3, Windows Server 2003 SP2, Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2012, and Windows RT. The vulnerability resides in the icardie.dll file which is part of the Windows Information Card authentication framework that facilitates single sign-on functionality for web services and applications.
The technical exploitation of this vulnerability occurs through a carefully crafted web page that leverages Internet Explorer's handling of ActiveX controls. When a user visits such a malicious webpage, the InformationCardSigninHelper control attempts to process malformed input data, resulting in an out-of-bounds write operation that can overwrite adjacent memory locations. This memory corruption typically occurs due to insufficient bounds checking within the ActiveX control's parameter validation logic, allowing attackers to manipulate memory contents beyond the intended buffer boundaries. The vulnerability falls under the Common Weakness Enumeration category CWE-129, which specifically addresses insufficient validation of length of input buffers, and more broadly relates to CWE-787, out-of-bounds write conditions that can lead to arbitrary code execution or system instability.
The operational impact of this vulnerability is severe and multifaceted, encompassing both remote code execution and denial of service capabilities. Attackers can leverage this flaw to execute arbitrary code with the privileges of the logged-in user, potentially leading to full system compromise. The vulnerability's exploitation in the wild during November 2013 demonstrates its practical threat level and widespread targeting of vulnerable systems. Additionally, the out-of-bounds write condition can also cause denial of service scenarios where the control crashes or becomes unstable, rendering the affected system unusable. According to the MITRE ATT&CK framework, this vulnerability maps to techniques involving exploitation of known vulnerabilities and privilege escalation, with the initial compromise often occurring through social engineering or drive-by download attacks that deliver the malicious web content to unsuspecting users.
Mitigation strategies for CVE-2013-3918 should focus on immediate remediation through Microsoft's security patches and updates, which address the underlying buffer overflow conditions in the ActiveX control. System administrators should implement the principle of least privilege by disabling ActiveX controls in Internet Explorer where possible, particularly in environments where users may encounter untrusted web content. Browser security enhancements including the use of enhanced protections such as Internet Explorer's SmartScreen filter and ActiveX filtering features can provide additional defense layers. Network-based mitigations such as firewalls and web application firewalls should be configured to block access to known malicious domains that may host exploit content. Additionally, organizations should conduct comprehensive vulnerability assessments to identify systems running affected versions of Windows and ensure that all security updates are properly deployed across the enterprise environment. The vulnerability also underscores the importance of regular security patch management and user education about the risks associated with visiting untrusted websites and downloading content from unknown sources.