VMware Workstation Shared Folders Directory Traversal Vulnerability
iDefense Security Advisory 04.27.07
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
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
Exploitation allows an attacker to read or write arbitrary files on the
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
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
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 =A9 2007 iDefense, Inc.
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