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Re: Vim: Insecure Temporary File Creation During Build: Arbitrary Code Execution
From: "Nikolai Weibull" <now () bitwi se>
Date: Fri, 18 Jul 2008 09:38:28 +0200
On Fri, Jul 18, 2008 at 00:54, Jan Minář <rdancer () rdancer org> wrote:
The attacker has to create the temporary file ``/tmp/Makefile-conf<PID>'' before it is first written to at (1). In the time between (1) and (2), arbitrary commands can be written to the file. They will be executed at (2).
Patch fixing this vulnerability can be found at the following URL: http://www.rdancer.org/vulnerablevim-configure.in.patch
Using mktemp is a lot safer than using $$, but the file can still be written to between the creation and setup of the file and the eval. Dealing with temporary files in shell scripts is always racy. This fixes the easily guessed PID-pattern problem and as mktemp creates its file in a hopefully non-shared directory, increases security a great deal, but it's still racy. Why not use pipes instead? eval "`cd /usr/lib/python2.4/config && (cat Makefile - <<'eof' __: @echo "python_MODLIBS='$(MODLIBS)'" @echo "python_LIBS='$(LIBS)'" @echo "python_SYSLIBS='$(SYSLIBS)'" @echo "python_LINKFORSHARED='$(LINKFORSHARED)'" eof ) | make -f - __ | sed '/ directory /d'`" (I really don't see the point of the sed. Isn't that information output to stderr anyway (in which case it should be suppressed?)) I'm not sure if this requires too much from make and sh, though. It works with Bash's sh emulation.
Current thread:
- Vim: Insecure Temporary File Creation During Build: Arbitrary Code Execution Jan Minář (Jul 18)
- Re: Vim: Insecure Temporary File Creation During Build: Arbitrary Code Execution Nikolai Weibull (Jul 18)
- Re: [Full-disclosure] Vim: Insecure Temporary File Creation During Build: Arbitrary Code Execution Robert Buchholz (Jul 25)