Microsoft Security Response Center

**Are the any prerequisites to a successful attack?** Yes, only systems with the IPSec service running are vulnerable to this attack.

**What type of privileges could an attacker gain through this vulnerability?** A local, authenticated attacker could gain elevated local system or administrator privileges through a vulnerability in the Win32k.sys driver.

**What type of information could be disclosed by this vulnerability?** The type of information that could be disclosed if an attacker successfully exploited this vulnerability is the contents of Kernel memory. An attacker could read the contents of Kernel memory from a user mode process.

**According to the score, privileges required is equal to low. In this situation, what does that mean?** An attacker with non-admin credentials can potentially carry out an exploit using this vulnerability. **How can an attacker exploit this vulnerability?** The authenticated attacker could take advantage of this vulnerability to execute malicious code through the RPC runtime. **What is RPC runtime?** See this article for more information on RPC and RPC Runtime.

**What type of privileges could an attacker gain through this vulnerability?** A local, authenticated attacker could gain elevated local system or administrator privileges through a vulnerability in the Win32k.sys driver.

**How could an attacker exploit this vulnerability?** In most situations, an unauthenticated attacker could send a specially crafted packet to a targeted server utilizing the HTTP Protocol Stack (http.sys) to process packets. **Is this wormable?** Yes. Microsoft recommends prioritizing the patching of affected servers.

**What configurations or versions could be at risk from this vulnerability?** This bypass could affect any Hyper-V configurations that are using Router Guard. **What is the exposure if the vulnerability was bypassed?** Certain packets that would normally be blocked or dropped could be processed. This could allow an attacker to bypass set policy, potentially influencing router paths.

**What information could be disclosed through this vulnerability?** An attacker could potentially read small portions of heap memory.

**How could an attacker exploit this vulnerability?** An authenticated attacker could run a specially crafted application on a vulnerable Hyper-V guest to exploit this vulnerability. **What privileges could an attacker gain?** An attacker who successfully exploited this vulnerability could potentially interact with processes of another Hyper-V guest hosted on the same Hyper-V host.

**What is the scope of this security update?** This update resolves an elevation of privilege vulnerability specific to Active Directory Domain Services environments with incoming trusts. Prior to this update, an attacker could elevate privileges across the trust boundary under certain conditions.