McAfee coverage for July 2021 CVE-2021-36934 "HiveNightmare/SeriousSAM" vulnerability

[AdithyanT]

Hi All,

McAfee is aware of the "HiveNightmare/SeriousSAM" vulnerability, CVE-2021-36934, and is investigating product countermeasures. This article will be updated as we learn more. 

Article Reference here: https://kc.mcafee.com/corporate/index?page=content&id=KB94710

Workaround
Microsoft's Security Response Center recommends restricting access to the contents of %windir%\system32\config\ and deleting any Volume Shadow Copy Service (VSS) shadow copies that were created before restricting access. For more information, see: Microsoft update guide on CVE-2021-36934.

[AdithyanT · Accepted solution]

Solution via Expert rule:

Rule Name	Block CVE-2021-36934: 'HiveNightmare/SeriousSam'
Severity	High
Action	Block Report
Rule type	Files
Rule content	Rule {     Process {         Include AggregateMatch -xtype "ex1" {             Exclude VTP_PRIVILEGES -type BITMASK { -v 0x8 }         }         Include AggregateMatch -xtype "ex2" {             Exclude GROUP_SID { -v "S-1-16-16384" }             Exclude GROUP_SID { -v "S-1-16-12288" }         }         Include AggregateMatch -xtype "ex3" {             Exclude OBJECT_NAME { -v "vssadmin.exe" }         }     }     Target {         Match FILE {             Include OBJECT_NAME { -v "**\\windows\\system32\\config\\SAM" }             Include OBJECT_NAME { -v "**\\windows\\system32\\config\\SYSTEM" }             Include OBJECT_NAME { -v "**\\windows\\system32\\config\\SOFTWARE" }             Include OBJECT_NAME { -v "**\\windows\\system32\\config\\SECURITY" }             Include -access "READ"         }     } }

Edit: Edited the rule on 24 July 2021 to match the new rule updated on KBA.

[SWISS]

I mean HOW do you know you don't target software that also uses vssadmin.exe like Veaam, Acronis, DIsk2VHD or PowerShell Scripts which do a snapshot before they change large amount of critical things like Bloatware uninstallers etc.

How should we test that? It will take a week or so? How do you want to catch a 0day with a -7day_test?

Please Explain? Are we too stupid to understand?

And finally and for once explain if such an expert rules is posted here WHEN and FAST will it appear under regular EPO-Server and ENS so customers can activate it? How is that that process and timeline? Like the AMCORE at 17:00 CET or when?