7/2/2023 0 Comments Serious sam vulnerability![]() ![]() ![]() Finally, I will discuss mitigation measures. Next, I will demonstrate how Microsoft’s defenses can be bypassed to exploit SeriousSAM even on systems that are fully-patched by Microsoft’s Patch Tuesday update. In this blog post, I will first show how the SeriousSAM vulnerability can be exploited in its original form. Because of this, it is still possible to exploit the SeriousSAM vulnerability on patched systems under certain conditions. It turns out that the update is only a partial fix, as acknowledged by Microsoft’s advisory. The Microsoft Patch Tuesday update on Aug“addressed” SeriousSAM a.k.a. ![]() We will update this article with further information as it becomes available.Exploiting and Mitigating SeriousSAM / HiveNightmare ![]() The results show information about the process as well as the machine learning (ML) score, potentially unwanted application (PUA) score, local, and global reputation for the file corresponding to the process to aid in determining whether the file is suspicious or not. It is optimized to minimize the number of accesses to the Sophos File Journal to enable hunts over wider periods of time. This Live Discover query on Sophos Community, from Sophos MTR, will identify processes that have accessed either the SAM, SECURITY, or SYSTEM Registry hive files in Shadow volumes. For more information on how to delete shadow copies, see this Microsoft knowledgebase article.Delete any System Restore points and Shadow volumes that existed prior to restricting access to the contents of %windir%\system32\config.Identify whether Shadow volumes exist with either Command Prompt or PowerShell (Run as administrator):.Delete Volume Shadow Copy Service (VSS) shadow copies.Icacls $env:windir\system32\config\*.* /inheritance:e Windows PowerShell (Run as administrator):.Icacls %windir%\system32\config\*.* /inheritance:e Restrict access to the contents of %windir%\system32\config.This is still under investigation by Microsoft and a patch is not currently available however a workaround has been provided.īoth of these steps must be performed to prevent exploitation of this vulnerability.ĭeleting shadow copies may impact restore operations, including the ability to restore data with third-party backup applications that utilize the Volume Shadow Copy Service. This is the primary directory that contains the files for the Windows Registry, including the Security Account Manager (SAM) which stores users’ passwords.Īn attacker with the ability to execute code on a target host could exploit this vulnerability to elevate their privileges to SYSTEM.ĭue to the ACLs granting read access, Volume Shadow Copy Service (VSS) shadow copies of these files may exist, for instance as part of system restore points.įor more information, please read the article on Sophos Naked Security. Since Windows 10 build 1809, the Access Control Lists (ACLs) for %windir%\System32\config have been granting read access to non-admin users. HiveNightmare (CVE-2021-36934), also known as SeriousSAM, is a high severity zero-day elevation of privilege vulnerability in Windows currently under investigation by Microsoft. ![]()
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