unshield directory traversal

[Kurt Seifried <kseifried () redhat com>]

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=776193

Package: unshield
Version: 1.0-1
Tags: security

unshield is vulnerable to directory traversal via "../" sequences. As a
proof of concept, unpacking the attached InstallShield archive creates a
file in /tmp:

$ ls /tmp/moo
ls: cannot access /tmp/moo: No such file or directory

$ unshield x data1.cab
Cabinet: data1.cab
 extracting:
./Bovine_Files/../../../../../../../../../../../../../../../../../../../../../../../../../../../../../../../../../../../../../../tmp/moo
--------  -------
         1 files

$ ls /tmp/moo
/tmp/moo


-- System Information:
Debian Release: 8.0
 APT prefers unstable
 APT policy: (990, 'unstable'), (500, 'experimental')
Architecture: i386 (x86_64)
Foreign Architectures: amd64

Kernel: Linux 3.2.0-4-amd64 (SMP w/2 CPU cores)
Locale: LANG=C, LC_CTYPE=pl_PL.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: sysvinit (via /sbin/init)

Versions of packages unshield depends on:
ii  libc6         2.19-13
ii  libunshield0  1.0-1
ii  zlib1g        1:1.2.8.dfsg-2+b1

-- 
Kurt Seifried -- Red Hat -- Product Security -- Cloud
PGP A90B F995 7350 148F 66BF 7554 160D 4553 5E26 7993

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