CVE-2011-1787 in Player
Summary
by MITRE
Race condition in mount.vmhgfs in the VMware Host Guest File System (HGFS) in VMware Workstation 7.1.x before 7.1.4, VMware Player 3.1.x before 3.1.4, VMware Fusion 3.1.x before 3.1.3, VMware ESXi 3.5 though 4.1, and VMware ESX 3.0.3 through 4.1 allows guest OS users to gain privileges on the guest OS by mounting a filesystem on top of an arbitrary directory.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 11/08/2021
The vulnerability described in CVE-2011-1787 represents a critical race condition flaw within the VMware Host Guest File System implementation that affects multiple VMware products including workstation player fusion and enterprise virtualization platforms. This race condition exists in the mount.vmhgfs component which handles the mounting of guest operating system filesystems within VMware environments. The flaw specifically manifests when guest operating system users can exploit the timing window between directory creation and filesystem mounting operations to manipulate the filesystem hierarchy.
The technical nature of this vulnerability stems from improper synchronization mechanisms in the HGFS mounting process where the system fails to properly validate or secure directory access during the mount operation sequence. When a guest OS user attempts to mount a filesystem, the race condition allows them to position their mount point to overlap with an arbitrary directory on the guest system, effectively creating a privilege escalation vector. This occurs because the mounting process does not adequately verify that the target directory is properly secured or that no other concurrent operations are modifying the directory structure.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with the ability to manipulate the guest operating system's filesystem hierarchy in potentially dangerous ways. An attacker can mount a filesystem on top of critical system directories such as /bin, /etc, or other privileged locations, potentially allowing them to replace system binaries, modify configuration files, or gain elevated privileges within the guest environment. This creates a significant threat vector for attackers who wish to establish persistent access or escalate their privileges within virtualized environments. The vulnerability affects a wide range of VMware products including workstation player fusion and enterprise platforms, making it particularly concerning for organizations using multiple VMware solutions.
The exploitation of this race condition requires careful timing and understanding of the filesystem operations, but once successful, provides attackers with substantial control over the guest operating system. The vulnerability is particularly dangerous in enterprise environments where multiple virtual machines may be running with varying privilege levels, as it could allow attackers to move laterally between VMs or gain access to sensitive data. Security researchers have classified this vulnerability as a privilege escalation issue with potential for significant impact in virtualized environments. Organizations should immediately apply patches to all affected VMware products, including VMware Workstation 7.1.4, Player 3.1.4, Fusion 3.1.3, and the corresponding ESXi and ESX versions. The fix involves implementing proper synchronization mechanisms to prevent the race condition during filesystem mounting operations, ensuring that directory access is properly secured throughout the mount process. This vulnerability highlights the importance of proper concurrency control in virtualization software and demonstrates how seemingly minor implementation flaws can result in significant security implications within complex virtualized environments. The issue aligns with CWE-362 which addresses race conditions and ATT&CK technique T1059 which covers command and scripting interpreter usage in privilege escalation scenarios.