The first security advisory published by VMware in 2016 describes an important guest privilege escalation vulnerability in VMware Tools.
VMware Tools includes utilities designed to enhance the performance of the virtual machine (VM) guest operating system and improve VM management.
Dmitry Janushkevich from the Secunia Research Team discovered that the Shared Folders (HGFS) feature running on Windows is plagued by a memory corruption flaw (CVE-2015-6933) that can be exploited by an attacker to escalate their privileges in the guest operating system.
VMware has pointed out that the vulnerability cannot be exploited to escalate privileges from the guest operating system to the host, and host memory cannot be manipulated from the guest.
The vulnerability affects VMware ESXi 5.0, 5.1, 5.5 and 6.0, Workstation 11, Player 7, and Fusion 7. Workstation 12, Player 12 and Fusion 8 are not impacted.
VMware has patched the flaw with the release of 201512102-SG patches for ESXi, version 11.1.2 for Workstation, and version 7.1.2 for Player and Fusion. Once the patches and updates are installed, users need to update VMware Tools in all Windows guests that include the Shared Folders feature. As a workaround, users can simply remove the Shared Folders feature to prevent exploitation.
“VMware Tools installations initiated via vSphere (ESXi/vCenter) do not include the affected ‘Shared Folders’ (HGFS) feature unless a ‘Complete’ feature set was specified during the initial installation,” VMware noted in its advisory.