CVE-2014-0322: Microsoft Internet Explorer Use-After-Free Vulnerability

CVE-2014-0322 is a use-after-free vulnerability in Microsoft Internet Explorer that can allow a remote attacker to execute code on a vulnerable system. For IT and security teams, this class of browser flaw matters because successful exploitation can lead to full control of the endpoint under the user’s context, with potential for lateral movement, credential theft, or further payload delivery. Confirm exact scope and fixed builds against the vendor advisory.

CISA describes it as a use-after-free issue that permits remote code execution and directs organizations to apply updates per vendor instructions. Ransomware use is not documented for this CVE.

How it works

This vulnerability is classified as CWE-416 (use-after-free). In a use-after-free condition, the browser frees a block of memory but later continues to reference it. An attacker who can influence what occupies that memory can corrupt browser state and potentially redirect execution.

In practice for Internet Explorer, an attacker typically lures a user to crafted web content (for example via a malicious or compromised site). The content triggers the free-and-reuse sequence inside the browser’s rendering or scripting components. If the attacker controls the reused memory, they may achieve arbitrary code execution in the context of the logged-on user. Exact trigger mechanics and any required user interaction must be confirmed against the vendor advisory; do not rely on unverified public exploit descriptions.

Am I affected? How to find it in your systems

Internet Explorer has historically been present on Windows desktops and servers, including environments where it remains installed for legacy application compatibility even when another browser is the default. Inventory every Windows endpoint and identify whether Internet Explorer is installed or still invoked by line-of-business apps, ActiveX controls, or automated processes.

• Use software inventory (SCCM/ConfigMgr, Intune, WSUS reports, vulnerability scanners, or agent-based asset tools) to list hosts with Internet Explorer present and record the installed version/build.
• Compare those builds to the fixed versions listed in the Microsoft advisory for CVE-2014-0322; if your build is older than the remediated release, treat the host as affected until verified otherwise.
• Check Group Policy and application compatibility settings that force IE use (enterprise mode, document modes, or legacy web apps).
• For exploitation signs, review endpoint detection logs for unexpected IE child processes, crashes followed by suspicious process creation, anomalous network connections originating from iexplore.exe, or memory-corruption related alerts. Browser crash dumps and EDR telemetry around the time of web browsing may also surface indicators. Absence of alerts does not prove non-exploitation.

How to remediate

Patch first. Apply the Microsoft security update that addresses CVE-2014-0322 exactly as specified in the vendor advisory and CISA’s direction to apply updates per vendor instructions. Deploy through your normal channel (WSUS, Microsoft Update Catalog, Intune, or SCCM) and verify installation success across the estate.

• Prioritize internet-facing and high-risk user workstations, then jump servers and any hosts that still launch IE for internal apps.
• After patching, validate the IE build number matches the remediated version from the advisory.
• Where IE is no longer required, disable or remove it per Microsoft guidance and migrate remaining dependencies to a supported browser to shrink future attack surface.
• Enforce least privilege so that even successful browser exploits run with limited rights, and keep endpoint protection and attack-surface reduction rules enabled.

If you can't patch immediately

Implement compensating controls until the vendor update can be deployed:

• Network segmentation and egress filtering to limit what compromised browsers can reach.
• Application control or browser isolation (for example, restricting IE to a locked-down virtual environment or remote browser service) for users who still need it.
• Virtual patching via IPS/WAF rules that detect or block known exploit patterns for this vulnerability class, tuned to avoid breaking legitimate traffic; confirm rule coverage with your security vendor.
• Disable or restrict the affected component where feasible (for example, limiting IE use via software restriction policies, AppLocker/WDAC, or removing IE shortcuts and file associations).
• Heightened monitoring: alert on IE process anomalies, unusual child processes, and post-exploitation behaviors, and ensure EDR is in blocking mode where possible.
• User guidance to avoid untrusted sites and unsolicited links until patching is complete.

If your data may have been exposed

Actively exploited browser vulnerabilities can lead to endpoint compromise and subsequent data exposure. If you have indicators of exploitation or suspect a breach, follow your incident-response process: isolate affected hosts, preserve evidence, reset credentials, and assess lateral movement. You can also run a free exposure scan of your email addresses against known breach data to check whether associated accounts appear in prior dumps and to prioritize further monitoring and password hygiene.