VMware Workstation Shared Folders Directory Traversal Vulnerability
iDefense Security Advisory 04.27.07 http://labs.idefense.com/intelligence/vulnerabilities/ Apr 27, 2007
VMware Workstation is a software virtualization system which allows multiple virtual computers to run on a single system. For more information visit the following URL.
Remote exploitation of a design error in the "Shared Folders" feature of VMware Inc.'s VMware Workstation could allow an attacker to write arbitrary content from a guest system to arbitrary locations on the host system.
The "Shared Folders" feature of VMware Workstation allows folders on the physical "host" system to be shared with virtual "guest" systems. Due to a flaw in the code which validates that the filename is safe, an attacker or malicious code within the guest system can read or write files on the host system in the context of the user running Workstation.
Exploitation allows an attacker to read or write arbitrary files on the host system.
In order to exploit this vulnerability, the VMware system must have at least one folder shared. Although the "Shared Folders" feature is enabled by default, no folders are shared by default. If the 'Read Only' option for a shared folder is set, the attacker will only be able to read files from the host.
The documentation states that VMware Tools must be installed in order to use the "Shared Folders" feature. While this is true of normal use of the feature, VMware Tools is not required to exploit this vulnerability. The vulnerable functionality is supplied by the "Backdoor I/O Port" interface. Some details of the interface protocol are publicly available. These details provide a starting point which allow an attacker to reverse engineer enough of the protocol to implement their own tool for performing these operations.
iDefense confirmed this vulnerability to exist in VMware Workstation 5.5.3 build 34685 on a Windows XPSP2 host. Other versions may also be affected.
Disabling the "Shared Folders" feature in VMware will prevent exposure to this vulnerability.
VI. VENDOR RESPONSE
VMware Inc. has addressed this vulnerability by releasing new versions of their software. More information is available in the release notes provided by VMware Inc.
VII. CVE INFORMATION
The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2007-1744 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org/), which standardizes names for security problems.
VIII. DISCLOSURE TIMELINE
03/20/2007 Initial vendor notification 03/20/2007 Initial vendor response 04/27/2007 Coordinated public disclosure
This vulnerability was discovered by Greg MacManus of iDefense Labs.
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X. LEGAL NOTICES
Copyright © 2007 iDefense, Inc.
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