Xerox  Multi-Function Device Security Target 
 
70 
Copyright
 2013 Xerox Corporation. All rights reserved. 
after  the  job  has  completed,  the  files  are  overwritten,  and  this  is  called 
Immediate Image Overwrite (IIO).  
The TOE automatically starts an IIO procedure for all abnormally terminated 
copy, print, scan or fax jobs stored on the HDD prior to coming “on line” when 
any of the following occurs:  a reboot or once the MFD is turned back on after 
a power failure/disorderly shutdown.  
The  image  overwrite  security  function  can  also  be  invoked  manually  (on 
demand)  by  the  system  administrator  (ODIO).    Once  invoked,  the  ODIO 
cancels all print and scan jobs, halts the printer interface (network), performs 
the  overwrites,  and  then  the  network  controller  reboots.    A  scheduling 
function allows ODIO to be executed on a recurring basis as set up by the 
System Administrator. 
A standard ODIO overwrites all files written to temporary storage areas of the 
HDD.    A  full  ODIO  overwrites  those  files  as  well  as  the  Fax  mailbox/dial 
directory and Scan to mailbox data. 
An ODIO cannot be aborted from either the WebUI or LUI. 
TSF_IOW overwrites the contents of the reserved section on the hard disk 
using a three pass overwrite procedure.  
7.1.2.  Information Flow Security (TSF_FLOW) 
FPT_FDI_EXP.1  
The  only  physical  shared-medium  interface  of  the  TOE  is  the  network 
interface. 
The TOE controls and restricts the data/information flow from the LUI, 
document scanner and document feeder to the network interface by brokering 
all data through an intermidary subsystem. A connectivity subsystem further 
processes the data before sending it to the network interface. 
The TOE provides separation between the optional fax processing board and 
the network interface and therefore prevents an interconnection between the 
PSTN and the internal network.  This separation is realized in software, as by 
design,  these  interfaces  may  only  communicate  via  an  intermediary.    All 
internal command calls (API) and response messages for both the  network 
and fax interfaces are statically defined within the TOE. No user or system 
administrator is able to change their formats or functionalities.  
The fax software runs two independent processes, for sending and receiving 
job data through the fax card respectively. There is no internal communication 
between these two processes. 
The same job data will never be active on both the fax interface and network 
interface at the same time.  For network interface to fax interface (LanFax) 
jobs, the entire job must be received  as an image and buffered in memory 
before it is sent out through the fax interface.  Likewise, for fax interface to 
network  interface  (fax  forwarding  to  email)  jobs,  the  entire  job  must  be