High
CVE-2021-34448
CVE-2021-34448
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Technical Analysis
Looking at Microsoft’s advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-34448 shows very little information other than that this is a scripting engine vulnerability which is exploitable across a wide range of Windows OS versions and is exploitable remotely. Further investigation though shows that Cisco Talos at https://blog.talosintelligence.com/2021/07/microsoft-patch-tuesday-for-july-2021.html mentions that this vulnerability is a memory corruption vulnerability triggered when opening a maliciously crafted email or visiting a malicious website.
Further examination of https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-34448 using the Download column (which is not enabled by default but can be added) shows several references to IE Cumulative Update which suggests this is potentially an IE related vulnerability. Further examination of past advisories named in the same way like https://msrc.microsoft.com/en-us/security-guidance/advisory/CVE-2017-0224 shows that IE scripting engine vulnerabilities are also referenced using the same style of language, so it would seem this is a memory corruption vulnerability within IE’s scripting engine.
Users should ideally apply patches to fix this issue given it has been exploited in the wild already, however if this is not possible then users should disable JavaScript in their browsers as most scripting engine vulnerabilities rely on taking advantage of flaws in the JavaScript engine of a given browser, which requires the browser to have JavaScript enabled in the first place. Note that this will break the operation of most sites so patching is preferred where possible.
CVSS V3 Severity and Metrics
General Information
Vendors
- microsoft
Products
- windows 10 1507,
- windows 10 1607,
- windows 10 1809,
- windows 10 1909,
- windows 10 2004,
- windows 10 20h2,
- windows 10 21h1,
- windows 7 -,
- windows 8.1 -,
- windows rt 8.1 -,
- windows server 2008 r2,
- windows server 2012 -,
- windows server 2012 r2,
- windows server 2016,
- windows server 2019
Exploited in the Wild
