COMMAND
VMware
SYSTEMS AFFECTED
Linux Distributions with VMware 1.1.2 (build 364)
PROBLEM
'harakiri' found following. VMware stores temporary log files
within the /tmp directory. It does not check whether all of these
files exist prior to creation, resulting in the potential for a
symlink attack.
VMware is a commercial application that enables the operation of
"guest" operating systems within the host system. This is
performed via the use of Virtual Machine technology. Due to the
low-level requirements of VMware, it is necessary to run the
program at a high privilege level, typically root.
VMware creates the file "/tmp/vmware-log" on startup. The
existance and owner of the file is not checked prior to writing
startup information to the file. NOTE: VMware uses other files
in the /tmp directory. The one cited above is only a single
example.
Local users may create a symlink from an arbitrary file to
/tmp/vmware-log. When VMware is executed, the file pointed to by
the symlink will be overwritten. This may be used as a local
denial of service attack. There may also be a method to gain
elevated privileges via the symlink attack, though none is known
at this time.
SOLUTION
Wait for a fix from the vendor. Set $TMPDIR to something sane
like $HOME/tmpfiles. The use of the /tmp directory is default in
VMware, but configurable with the tmpDirectory = <directory>
setting in the .cfg file for the guest operating system, or with
the TMPDIR=<directory> setting in your shell environment. This
is documented on VMware's website.