Under what circumstances might this vulnerability be exploited other than as a denial of service attack against a Hyper-V host? 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 address read would not be returned to the guest VM. In most circumstances, this would result in a denial of service of the Hyper-V host (bugcheck) due to reading an unmapped address. It is possible to read from a memory mapped device register corresponding to a hardware device attached to the Hyper-V host which may trigger additional, hardware device specific side effects that could compromise the Hyper-V host's security. According to the CVSS metric, the Hyper-V attack vector is adjacent (AV:A). What does that mean for this vulnerability? Where the attack vector metric is Adjacent (A), this represents virtual machines connected via a Hyper-V Network Virtualization (HNV) logical network. This configuration forms an isolation boundary where the virtual machines within the virtual network can only communicate with each other. In this attack vector, the vulnerable component is bound to the network stack, but the attack is limited to systems configured to use the HNV network. According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability? Successful exploitation of this vulnerability requires an attacker to gather information specific to the environment and take additional actions prior to exploitation to prepare the target environment.
<a href="https://twitter.com/rthhh17">HongZhenhao</a> with <a href="https://twitter.com/tiangonglab">TianGong Team of Legendsec at Qi'anxin Group</a>