{"id":20122,"date":"2021-06-03T00:02:00","date_gmt":"2021-06-02T22:02:00","guid":{"rendered":"http:\/\/159.69.82.204\/win\/?p=20122"},"modified":"2021-06-02T16:13:29","modified_gmt":"2021-06-02T14:13:29","slug":"poc-fr-hyper-v-schwachstelle-in-vmswitch-sys-cve-2021-28476","status":"publish","type":"post","link":"https:\/\/borncity.com\/win\/2021\/06\/03\/poc-fr-hyper-v-schwachstelle-in-vmswitch-sys-cve-2021-28476\/","title":{"rendered":"PoC for Hyper-V vulnerability (CVE-2021-28476) in vmswitch.sys"},"content":{"rendered":"

\"Windows\"[German<\/a>]There is a remote code execution vulnerability (CVE-2021-28476) in Microsoft's Hyper-V virtualization solution that allows a guest-to-host attack. Microsoft provided security updates in May 2021, so the vulnerability could be closed. Now a security researcher has published a proof of concept (PoC) for the vulnerability in vmswitch.sys. <\/p>\n

<\/p>\n

Hyper-V vulnerability CVE-2021-28476<\/h2>\n

\"\"is Microsoft's virtualization technology built into Windows Server (and also clients starting with Windows 8). The CVE-2021-28476 vulnerability in the Hyper-V module vmswitch.sys allows remote code execution from the guest operating system on the host. Microsoft writes about the vulnerability:<\/p>\n

\n

This issue allows a guest VM to force the Hyper-V host's kernel to read from an arbitrary, potentially invalid address. The contents of the read address would not be returned to the guest VM. Under most circumstances, this would result in a denial of service from the Hyper-V host (bugcheck, i.e., bluescreen) due to reading an unassigned address. However, it is possible to read from a device register mapped in memory that corresponds to a hardware device attached to the Hyper-V host, which could trigger additional hardware device-specific side effects that could compromise the security of the Hyper-V host.<\/p>\n<\/blockquote>\n

The vulnerability received a CVSS score of 8.6, and Microsoft has released security updates<\/a> for Windows clients from Windows 7 SP1 to Windows 10 version 1607, and Windows Server 2008 R2 to Windows Server 2016, as of May 11, 2021 (see also list of links at end of article). <\/p>\n

Proof of Concept for CVE-2021-28476<\/h2>\n

Axel Souchet has written an exploit as a proof of concept that demonstrates this remote code execution from the Hyper-V guest system on the host, as he announced in the following tweet<\/a>.<\/p>\n

\"Proof<\/a><\/p>\n

Details may be found on Github<\/a> – administrators should install the May 2021 security updates on the affected machines if they have not already done so.  <\/p>\n

Similar articles:
<\/strong>Patchday: Windows 10-Updates (May 11, 2021)<\/a>
Patchday: Windows 8.1\/Server 2012-Updates (May 11, 2021)<\/a>
Patchday: Windows 7\/Server 2008 R2-Updates (May 11, 2021)<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

[German]There is a remote code execution vulnerability (CVE-2021-28476) in Microsoft's Hyper-V virtualization solution that allows a guest-to-host attack. Microsoft provided security updates in May 2021, so the vulnerability could be closed. Now a security researcher has published a proof of … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[580,1218,2],"tags":[69,1405],"class_list":["post-20122","post","type-post","status-publish","format-standard","hentry","category-security","category-virtualization","category-windows","tag-security","tag-virtualisierung"],"_links":{"self":[{"href":"https:\/\/borncity.com\/win\/wp-json\/wp\/v2\/posts\/20122","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/borncity.com\/win\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/borncity.com\/win\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/borncity.com\/win\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/borncity.com\/win\/wp-json\/wp\/v2\/comments?post=20122"}],"version-history":[{"count":0,"href":"https:\/\/borncity.com\/win\/wp-json\/wp\/v2\/posts\/20122\/revisions"}],"wp:attachment":[{"href":"https:\/\/borncity.com\/win\/wp-json\/wp\/v2\/media?parent=20122"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/borncity.com\/win\/wp-json\/wp\/v2\/categories?post=20122"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/borncity.com\/win\/wp-json\/wp\/v2\/tags?post=20122"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}