source: https://www.securityfocus.com/bid/81/info

netconfig creates the file /tmp/tmpmsg insecurely and follows symbolic links. An attacker can create a symbolic link from /tmp/tmpmsg to any file and wait for root to run the program. This will clober the target file. The file created has permissions -rw-r--r--.

$ ln -s /tmp/tmpmsg /etc/passwd
< wait for root to run netconfig >