Microsoft Internet Explorer 11 iertutil LCIEGetTypedComponentFromThread use after free ⚔ [Disputed]

Summaryinfo

A vulnerability described as critical has been identified in Microsoft Internet Explorer 11. Affected is the function LCIEGetTypedComponentFromThread of the component iertutil. Such manipulation leads to use after free. The attack can be executed remotely. There is not any exploit available. There is ongoing doubt regarding the real existence of this vulnerability.

Detailsinfo

A vulnerability was found in Microsoft Internet Explorer 11 (Web Browser) and classified as critical. Affected by this issue is the function LCIEGetTypedComponentFromThread of the component iertutil. The manipulation with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability.

The weakness was released 11/18/2016 by Berend-Jan Wever (SkyLined) as Microsoft Internet Explorer 11 iertutil LCIEGetTypedComponentFromThread use-after-free details as not defined mailinglist post (Full-Disclosure). The advisory is available at seclists.org. The vendor was not involved in the coordination of the public release. The attack may be launched remotely. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $25k-$100k at the moment (estimation calculated on 04/07/2017). It is expected to see the exploit prices for this product decreasing in the near future. The advisory points out:

This looks like a pretty straightforward use-after-free, but I did not investigate at what point in the repro the memory gets freed and when it gets re-used, so I do not know if an attacker has any chance to force reallocation of the freed memory before reuse. The issue can be triggered with MemGC enabled; the object that is freed does not appear to be protected by MemGC. The repro requires that MSIE is run in single-process mode in order to trigger the use-after-free. It is not known if it is possible to tweak the repro to have MSIE take a similar code-path that leads to a use-after-free when MSIE is not in single-process mode.

The real existence of this vulnerability is still doubted at the moment. The advisory illustrates:

ZDI reports they are unable to reproduce the issue.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Type

• Web Browser

Vendor

• Microsoft

Name

• Internet Explorer

Version

• 11

License

• commercial

Support

• end of life

Website

• Vendor: https://www.microsoft.com/

CPE 2.3info

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CPE 2.2info

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