CVE-2010-0249: Microsoft Internet Explorer Use-After-Free Vulnerability
Microsoft Internet Explorer contains an use-after-free vulnerability that could allow remote attackers to execute arbitrary code by accessing a pointer associated with a deleted object. The impacted product could be end-of-life (EoL) and/or end-of-service (EoS). Users should discontinue product utilization.
Overview
Internet Explorer versions 6 through 8 contain a use-after-free flaw in the browser's HTML object memory handling. When a user visits a specially crafted web page or opens a malicious Office document containing an ActiveX control, the browser accesses a pointer to memory that has already been freed, allowing an attacker to execute arbitrary code in the context of the logged-in user. This vulnerability was actively exploited in late 2009 and early 2010 as part of Operation Aurora, a targeted attack campaign against major technology companies.
Vulnerability details
The flaw is a use-after-free condition (CWE-416) in Internet Explorer's object lifecycle management. When certain HTML objects are deleted or incorrectly initialized, IE retains a dangling pointer to the freed memory region rather than invalidating it. Because the browser does not verify that the pointer still references valid, allocated memory before dereferencing it, attacker-controlled content can trigger the access at a predictable point in the page rendering or scripting path, corrupting memory in a way that redirects execution.
An attacker delivers a specially crafted HTML page or an Office document embedding a malicious ActiveX control to the victim, typically via a link or email attachment. When the victim opens the content in an affected version of Internet Explorer, the dangling pointer is accessed, and the attacker gains arbitrary code execution in the security context of the logged-in user. Users running with administrative rights face full system compromise; those with limited accounts face reduced but still significant impact. No authentication or prior access to the target system is required on the attacker's part.
Severity and impact
Exploitation status
This vulnerability is confirmed as actively exploited in the wild — it is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog.
Detection and monitoring
- Monitor the Windows Application event log (Event ID 1000) for iexplore.exe crashes with exception code 0xc0000005 (access violation) in modules outside the standard IE binary set, particularly where the faulting module is an unexpected or unsigned DLL, which may indicate heap manipulation during exploitation rather than a routine crash.
- Check for child processes spawned by iexplore.exe (such as cmd.exe, powershell.exe, or wscript.exe) that have no corresponding user-initiated action; a browser process creating a command shell is not normal behavior and is a strong indicator of successful code execution following exploitation.
Remediation
Additional hardening
- Apply Microsoft Security Bulletin MS10-002, which addresses this vulnerability across Internet Explorer 5.01, 6, 6 SP1, 7, and 8; if the product is end-of-life and the patch cannot be applied, discontinue use per CISA guidance.
- Enable Data Execution Prevention (DEP) for Internet Explorer 6 and 7; Microsoft confirmed DEP as a partial mitigation that can block attacker-supplied shellcode execution in some exploitation scenarios, though it is not a complete substitute for patching.
- Set the Internet zone security level to High and disable Active Scripting and ActiveX controls in the browser and in Microsoft Office to remove the primary delivery vectors for this vulnerability.
- Restrict or block access to Internet Explorer entirely on systems where it is not operationally required, and enforce browsing through a modern, supported browser to reduce attack surface.
Key dates
References
- http://support.microsoft.com/kb/979352
- https://docs.microsoft.com/en-us/security-updates/securitybulletins/2010/ms10-002
- https://learn.microsoft.com/en-us/security-updates/SecurityAdvisories/2010/979352
- https://nvd.nist.gov/vuln/detail/CVE-2010-0249
- http://www.kb.cert.org/vuls/id/492515
- http://blogs.technet.com/msrc/archive/2010/01/14/security-advisory-979352.aspx
Frequently asked questions
Does CVE-2010-0249 affect my FedRAMP authorization?
If Microsoft Internet Explorer runs inside your authorization boundary, yes, this matters now. CVE-2010-0249 appears in CISA's Known Exploited Vulnerabilities (KEV) catalog, and its June 3, 2026 remediation deadline has already passed. For a FedRAMP-authorized service, an unpatched KEV is an assessor finding. An overdue one is visible to both your assessor and your sponsoring agency. At this point, your path is either to remediate it or formally document the mitigation and the delay.
How does Knox help me handle CVE-2010-0249?
Knox does not patch Microsoft Internet Explorer on your behalf. Remediation is your responsibility under the FedRAMP shared-responsibility model. What Knox provides is the pre-authorized, single-tenant boundary to remediate within, plus Knox's automated continuous monitoring platform and audit-artifact coverage that support your documentation posture heading into your next assessment. Applying the fix is yours to own; managing your compliance posture while you do it is not something you have to handle alone.
How does Knox's monitoring help with vulnerabilities like this?
Knox's automated continuous monitoring platform watches your environment continuously for newly disclosed vulnerabilities and compliance issues, including cases like CVE-2010-0249. Exposure surfaces during ongoing monitoring rather than only when an assessor flags it at review time, giving your team earlier visibility and more room to act.
How do I get FedRAMP authorized with Knox?
Knox runs a FedRAMP-as-a-Service platform. It gives SaaS vendors a pre-authorized cloud boundary on AWS, Azure, and GCP. Your application inherits 60-80% of the required security controls. You reach FedRAMP authorization in about 90 days for roughly 90% less than the traditional $3.5M path. Book a meeting and Knox will map your path to authorization.
CVE-2010-0249's remediation deadline of June 3, 2026 has passed. What happens now?
If CVE-2010-0249 remains unremediated, it is already a Plan of Action and Milestones (POA&M) item. A growing POA&M list is what turns a routine continuous-monitoring review into a difficult agency conversation. Closing it out now and documenting the delay is what keeps your authorization clean and your agency relationship intact.
Ready to achieve FedRAMP authorization in 90 days or less?
Schedule a meeting to discuss scope, parse readiness, and map your company’s accelerated path to FedRAMP authorization.
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