From: Chris McDonald STEWS-IM-CM-S (1/26/93) To: orvis%llnl.gov@wsmr-simtel20.ar, Mail*Link¨ SMTP Product Test 21 ****************************************************************************** PT-21 March 1991 ****************************************************************************** 1. Product Description: ZERODISK is a public domain (freeware) program to overwrite unallocated disk blocks. 2. Product Acquisition: ZERODISK is available in the MS-DOS repository on the USAISC-White Sands host simtel20. The author of the program is Steve Creps. The program is in the path: pd1:zerodisk.arc.1. 3. Product Tester: Chris Mc Donald, Computer Systems Analyst, Directorate of Information Management, White Sands Missile Range, NM 88002-5030, DSN 258-7548 or DDN: cmcdonal@wsmr-emh03.army.mil 4. Product Test: a. In February 1991 I was asked by a customer for a list of programs, available on simtel20, which can overwrite unclassified-sensitive information. In the process of that search I came across ZERODISK. Although there are at least two dozen different public domain and shareware programs available in the repository which address overwriting and permanent destruction of data in a file, this program was different from the rest. For this reason I am issuing a product test report. b. The customer in question had realized that the basic MS-DOS delete and erase commands do not actually overwrite or destroy information contained in the file. While this may seem to be a self-evident fact, users of MS-DOS systems do not necessarily read the documentation provided to them; nor do they necessarily receive any formal instruction on MS-DOS commands. Since there are dozens of utilities of varying degrees of sophistication which can recover data under the appropriate set of circumstances, data confidentiality should be a concern for those users who rely exclusively on the standard MS-DOS commands. c. With one or two exceptions the other public domain and shareware programs on simtel20 overwrite a file because a user designates the file or groups of files to be overwritten. These programs may not necessarily be difficult to understand, but they do require a user to type a specific syntax to issue commands. Most importantly, these programs require a user to indicate a file name or file specification (i.e., *.com, *.bat, etc.). The high-end shareware packages have dozens of options and usually provide menu-driven instructions. But what if a user does not want to remember syntax, or options, or file names? Then ZERODISK is the answer. d. The program overwrites all unallocated disk blocks by writing zeroes to a temporary file until there is no more space left on the given device. One invokes the program by entering: zerodisk. One has the option to specify the drive, such as zerodisk a:; otherwise the device containing the current zerodisk program is zeroed. The program does not touch any existing files. It looks only for those files that have been deleted or erased with the MS-DOS commands as well as overwriting all other unallocated disk space. e. The best use of the program came up inadvertently when another user gave me a disk with several text files on it. After I ran all of my anti-viral scanning programs against the disk with negative results, I decided to view the disk with Norton Utilities. I noticed that the user had deleted several files and decided to see if I could recover the deleted files. Needless to say the recovery operation was successful. In the process I retrieved the user's Standard Form 171 information which he had submitted to another government agency. I also recovered other personal information which clearly the user had never intended me to see. f. I tested ZERODISK on a variety of different systems, MS-DOS 3.0 or higher, with no problems encountered. In all cases the unallocated disk blocks were overwritten with zeros. Attempts to recovery the information using Norton Utilities and Professional Master Key were unsuccessful. The time to overwrite unallocated disk space on a floppy is acceptable. Execution of ZERODISK on a hard drive can be slow, depending upon the size of the drive and upon the amount of unallocated space which will actually be overwritten. 5. Product Advantages: a. ZERODISK is free and does what it says it will do. b. If one is in the business of passing information to other people on floppy disks, one can now deny the opportunity for "browsing". c. There are no complicated syntax statements to remember. 6. Product Disadvantages: a. ZERODISK can only address the destruction of unclassified-sensitive information. It provides a single overwrite which during the test was sufficient to defeat recovery by several software utilities. While a user could obviously invoke the program an unlimited amount of times, the National Security Agency has very specific criteria on the declassification of Type 1 classified magnetic media. b. The program has no formal certification or endorsement from any official group. Approval of the program will probably require the authorization of respective information system security officers, or whoever within an organization is responsible for data security. 7. Comments: The emphasis within military departments has been to ensure that no "remanence" of classified national defense information remains on data media. Concern for unclassified-sensitive information has never generated the same type of emphasis. While a commercial program like Norton Utilities will allow a user to overwrite erased and unallocated disk space, every user will simply not have a legal copy available for use. On the other hand, ZERODISK can be on everyone's system as a tool. [The opinions expressed in this evaluation are those of the author, and should not be taken as representing official Department of Army positions or a commercial endorsement.] 2 ------------------ RFC822 Header Follows ------------------ Received: by internetqm.llnl.gov with SMTP;26 Jan 1993 21:23:57 U Received: from icdc.llnl.gov by icdc.llnl.gov (PMDF #12441) id <01GTZM5E3GOGERWQLD@icdc.llnl.gov>; Tue, 26 Jan 1993 21:23 PST Received: from pierce.llnl.gov by icdc.llnl.gov (PMDF #12441) id <01GTZM4XY0YOERWQFW@icdc.llnl.gov>; Tue, 26 Jan 1993 21:23 PST Received: by pierce.llnl.gov (4.1/LLNL-1.18/llnl.gov-05.92) id AA16527; Tue, 26 Jan 93 21:18:21 PST Received: from WSMR-SIMTEL20.ARMY.MIL by pierce.llnl.gov (4.1/LLNL-1.18/llnl.gov-05.92) id AA16471; Tue, 26 Jan 93 21:16:03 PST Received: from wsmr-emh03.army.mil by WSMR-SIMTEL20.ARMY.MIL with TCP; Tue, 26 Jan 1993 22:15:10 -0700 (MST) Resent-date: Tue, 26 Jan 1993 21:23 PST Date: Tue, 26 Jan 93 21:53:51 MST From: Chris McDonald STEWS-IM-CM-S Subject: Product Test 21 Resent-to: BILL_ORVIS@QUICKMAIL.llnl.GOV To: orvis%llnl.gov@wsmr-simtel20.army.MIL Resent-message-id: <01GTZM5E3GOGERWQLD@icdc.llnl.gov> Message-id: <9301270516.AA16471@pierce.llnl.gov> X-Envelope-to: BILL_ORVIS@QUICKMAIL.llnl.gov X-VMS-To: IN%"orvis%llnl.gov@wsmr-simtel20.army.MIL" ======================================================================