CISA’s required action for CVE-2013-0074 is to the impacted product is end-of-life and should be disconnected if still in use. In practice, find every instance of Microsoft Silverlight in your estate, apply the vendor security update or documented mitigation, and if no fix can be applied, remove internet exposure or take the product out of service. After patching, review logs for signs of earlier exploitation, because attackers used this flaw in the wild.
What a safe Silverlight remediation plan looks like
For this CVE, the practical answer is not “patch and move on.” Silverlight is end-of-life, so exposure management matters as much as the update itself. Start by locating every installation, confirm whether it is actually reachable from the internet or only used internally, and treat any instance you cannot update as a removal or isolation candidate.
When a vendor fix or documented mitigation exists, apply it to every reachable instance and then verify the affected hosts are no longer publicly accessible. If the product still exists only because of a legacy workflow, the safer control is to contain that workflow until the dependency can be retired.
How to reduce exposure when patching is delayed
The key decision is whether the vulnerable component can remain in service without being exposed to untrusted traffic. If the answer is no, mitigation should focus on taking the product out of service, restricting network paths, and removing browser-facing access rather than waiting for a “perfect” fix.
Use Zero-Day and Exploited Vulnerabilities Guide for the same emergency mindset that applies here: active exploitation changes the priority from normal patching to immediate containment, verification, and post-fix hunting.
That same triage approach is reinforced by the Vulnerability Management Guide, which is most useful when you need to decide what gets handled first, what can wait under exception, and how to confirm remediation actually happened.
What to check after remediation
Once the update or mitigation is in place, assume the flaw may already have been used against exposed systems. Review web, host, and endpoint logs for unusual process launches, unexpected network connections, or signs that the browser plugin was used as an initial access path.
It is also worth validating whether any systems still reference Silverlight in application code, configuration, or published content. A patch that leaves the dependency callable from a public site, internal portal, or old workstation image is not a real remediation.
Risk and Threat Considerations
This vulnerability is risky because it sits in a legacy client component that attackers can reach through ordinary user browsing. If the product remains installed and reachable, exploitation can become a low-friction entry point for initial compromise, especially where legacy applications keep it exposed longer than intended.
Failure mechanism: A user or system loads the vulnerable Silverlight component, the flaw is triggered during normal interaction, and the attacker uses the resulting execution path to establish foothold or run follow-on activity.
Impact: The likely outcomes are unauthorized code execution, endpoint compromise, and a need to investigate whether credentials, sessions, or adjacent systems were touched after the initial exploit.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
CIS Controls v8, NIST SP 800-53 Rev 5 and NIST CSF 2.0 set the technical controls, while ISO/IEC 27001:2022 defines the regulatory obligations.
| Framework | Control / Reference | Relevance |
|---|---|---|
| CIS Controls v8 | CIS-4 — Secure Configuration of Enterprise Assets and Software | Silverlight remediation depends on removing or restricting unsafe legacy software exposure. |
| CIS-7 — Continuous Vulnerability Management | This CVE requires prioritisation, patching, exception handling, and verification after remediation. | |
| CIS-12 — Network Infrastructure Management | Mitigation may require removing internet exposure when patching cannot happen immediately. | |
| Recommendation — Inventory Silverlight, harden or remove exposed instances, and disable unnecessary internet access. Prioritise the fix, track exceptions, and verify the vulnerable component is no longer exploitable. Restrict network paths and isolate any remaining Silverlight-dependent systems. | ||
| NIST SP 800-53 Rev 5 | SI-2 — Flaw Remediation | The page is about patching or mitigating a known vulnerability and validating remediation. |
| RA-5 — Vulnerability Monitoring and Scanning | Exposure discovery and post-remediation verification are central to the answer. | |
| CA-7 — Continuous Monitoring | The answer requires checking logs for earlier exploitation and confirming the control stayed effective. | |
| Recommendation — Apply the vendor update or mitigation and confirm the flaw is remediated across the estate. Scan for Silverlight instances, confirm exposure, and reassess after remediation. Monitor hosts and logs for signs of exploitation before and after remediation. | ||
| ISO/IEC 27001:2022 | A.8.8 — Management of technical vulnerabilities | The subject is operational handling of an exploited vulnerability in software assets. |
| A.8.9 — Configuration management | Removing exposure or disabling the product is a configuration control decision. | |
| Recommendation — Track the vulnerable software, apply the fix, and document compensating controls when patching is delayed. Disable unnecessary Silverlight exposure and remove legacy dependencies from production systems. | ||
| NIST CSF 2.0 | PR.IP-12 — Vulnerability Management | The question is fundamentally about remediation of a known exploited weakness. |
| DE.CM-01 — Networks and network services are monitored | Post-patch hunting depends on monitoring for exploitation evidence and suspicious activity. | |
| Recommendation — Treat the CVE as a managed vulnerability, not a one-off patch task, and close it with verification. Monitor logs and network activity for signs of exploitation after remediation. | ||
Practitioner Guidance
What to prioritise: Find every Silverlight instance first, then separate them into three buckets, patchable, isolateable, and must-retire. That ordering matters because the main risk is not just the CVE itself, it is any surviving internet-facing dependency on an abandoned client technology.
What to verify: Confirm both the update state and the exposure state. A host can be “patched” yet still be operationally unsafe if the application remains reachable from untrusted networks or still depends on the vulnerable plugin for business use.
Decision rule: If the affected system is still externally exposed and you cannot immediately apply the vendor update or documented mitigation, disconnect it or remove the Silverlight dependency before accepting further exposure.
Practitioner takeaway: For end-of-life components, remediation is a containment problem as much as a patching problem, and the safer outcome is often removal of the dependency rather than preservation of the platform.
Related resources from NHI Mgmt Group
- How do you patch or mitigate CVE-2013-3896 (Microsoft Silverlight Information Disclosure)?
- CVE-2013-0074 (Microsoft Silverlight Double Dereference)
- How do you patch or mitigate CVE-2013-3893 (Microsoft Internet Explorer Resource Management Errors)?
- How do you patch or mitigate CVE-2023-29360 (Microsoft Streaming Service Untrusted Pointer Dereference)?