Se­curely Delete Data With Eraser

Maximum PC - - R&D - –NATE DRAKE

YOU’LL NEED THIS

ERASER Down­load this free tool from

http://eraser.heidi.ie. THE REV­E­LA­TIONS BY ED­WARD SNOW­DEN about NSA spy­ing ac­tiv­i­ties and the re­cent in­tro­duc­tion of strin­gent data pro­tec­tion laws in the EU have left ev­ery­one, from pri­vacy-minded in­di­vid­u­als to big busi­nesses, wor­ried about data se­cu­rity. As any power user knows, any files that are nom­i­nally “deleted” by Win­dows usu­ally re­main on your hard drive. The OS sim­ply changes a few bits in the file header to tell the sys­tem the data is no longer re­quired. As use­ful as this is for le­git­i­mate users who may have deleted data by ac­ci­dent, bad ac­tors, such as hack­ers, can use freely down­load­able dig­i­tal foren­sic tools to re­cover your files in sec­onds.

Eraser, which comes to us cour­tesy of Heidi Com­put­ers in Wick­low, Ire­land, seeks to re­store the bal­ance. This free util­ity works by re­peat­edly over­writ­ing ev­ery bit of data in files or fold­ers you se­lect to delete it se­curely. Eraser is highly cus­tom­iz­a­ble: You can choose your own era­sure method, such as seven passes of pseudo-ran­dom data, and can even au­to­mate tasks, such as over­writ­ing free space on your hard drive. While Eraser isn’t com­pletely ef­fec­tive when it comes to flash mem­ory (see box­out, below-right) and more ad­vanced foren­sic tech­niques, you can gain some peace of mind know­ing you’re us­ing the very best era­sure meth­ods avail­able. 1 SET UP ERASER Open your web browser of choice and nav­i­gate to https://eraser. heidi.ie/down­load/. Click the “Down­load” tab and then choose the most re­cent stable ver­sion of Eraser, which is at the top of the list. Your browser is now redi­rected to Source Forge, which hosts the in­stal­la­tion files. Win­dows 10 dis­plays a se­cu­rity alert at this stage. Click “Yes” to be­gin in­stal­la­tion. The setup wizard first tries to in­stall the .NET Frame­work 4 on your ma­chine. If this is al­ready in­stalled on your ver­sion of Win­dows, you may see a sys­tem prompt. Click “Close” to pro­ceed. Se­lect “Next” on the wel­come screen, and check “I ac­cept the terms in the li­cense agree­ment.”

>> The wizard now asks you to choose an in­stal­la­tion type. A “Typ­i­cal” in­stall in­cor­po­rates of all Eraser’s main fea­tures. Choose a “Com­plete” in­stal­la­tion if you want to in­clude ad­di­tional func­tions, such as shell ex­ten­sions. Click the “In­stall” but­ton once you’ve cho­sen the type of in­stal­la­tion you want, then click “Fin­ish” to close the setup wizard. 2 ERASE DATA If you chose to in­stall shell ex­ten­sions, you can ac­cess Eraser with just a few clicks of your mouse. Open the File Ex­plorer, and nav­i­gate to the file or folder you wish to se­curely delete. Right-click to open the con­text menu, and move your mouse to “Eraser,” then choose “Erase” [ Im­age A]. The first time you do this in Win­dows 10, you’ll need to click “Yes” to grant Eraser per­mis­sion to make changes.

>> Eraser asks you to con­firm be­fore pro­ceed­ing. Re­mem­ber that any data re­moved will not be stored in the Re­cy­cle Bin prior to dele­tion, so care­fully check you have the right in­for­ma­tion be­fore click­ing “Yes.” Eraser dis­plays a no­ti­fi­ca­tion read­ing “Task Com­pleted” once your data has been se­curely erased. This may take some time, de­pend­ing on Eraser’s con­fig­u­ra­tion. 3 CON­FIG­URE ERASER SET­TINGS By de­fault, Eraser uses the Gut­mann method to delete files, which in­volves over­writ­ing data 35 times. While this is ul­tra-se­cure, it’s usu­ally overkill for most users, and can take hours or days to com­plete for larger files. For­tu­nately, Eraser sup­ports a num­ber of dif­fer­ent meth­ods to re­move data.

>> Launch Eraser and click “Set­tings.” Find the “Erase Set­tings” sec­tion, and se­lect the drop-down menu marked “De­fault file era­sure method.” The US DoD (De­part­ment of De­fense) stan­dards for eras­ing data in­volve ei­ther three or seven passes, de­pend­ing on the sen­si­tiv­ity of the in­for­ma­tion. While the­o­ret­i­cally not as se­cure as the Gut­mann method, they are much more ef­fi­cient. Click “Save Set­tings” at the top-right to con­firm changes.

4 PLAU­SI­BLE DENIABILITY While delet­ing files with Eraser makes them very dif­fi­cult to re­cover, any­one with ac­cess to your hard drive can po­ten­tially view the clus­ters of pseudo-ran­dom data on your drive, and re­al­ize that you have some­thing to hide. Mer­ci­fully, Eraser sup­ports “plau­si­ble deniability.” This works by plac­ing a harm­less­look­ing file, such as an MP3, over erased data, mak­ing it much more dif­fi­cult to tell where sen­si­tive files were lo­cated pre­vi­ously. To do this, first choose a folder to use for de­coy files, such as a mu­sic al­bum. Open Era­sure’s set­tings, and check “Re­place erased files with the fol­low­ing files to al­low plau­si­ble deniability.” Next, click “Add folder,” and se­lect your cho­sen files [ Im­age B]. Click “Save Set­tings” once you are done.

>> Note that with the ad­vent of file jour­nal­ing and SSDs, plau­si­ble deniability has be­come dif­fi­cult to achieve in prac­tice. We strongly rec­om­mend us­ing full-drive en­cryp­tion (see “SSDs: A Spe­cial Case” below). 5 SCHED­UL­ING TASKS Eraser sup­ports au­to­mated dele­tion of data [ Im­age C]. This is use­ful for re­mov­ing files in ob­scure lo­ca­tions, such your web browser’s cache.

>> Click “Erase Sched­ule,” then se­lect “New Task.” Un­der “Task Prop­er­ties,” first en­ter a mean­ing­ful name in the name field, such as “Erase Google Chrome cache.” Choose “Re­cur­ring” un­der “Task Type,” then click “Add Data.” In the new win­dow, se­lect “Tar­get type”—for ex­am­ple, “files in a folder”—and choose an era­sure method, such as “Gut­mann.” Use “Browse” to en­ter the file or folder path, then click “OK” to con­firm. Fi­nally, click the “Sched­ule” tab to de­ter­mine the time and fre­quency of your new task, such as @ 13.30 daily. Click “OK” to set your new sched­uled task.

>> You can also use this fea­ture to reg­u­larly erase free space on your hard drive. Sim­ply choose “Un­used disk space” in the “Add Data” sec­tion. You can also man­u­ally over­write free space on any drive by right-click­ing it in File Ex­plorer, and choos­ing “Eraser > Erase Un­used Space.” 6 SE­CURE MOVE Eraser also in­cor­po­rates a handy fea­ture for mov­ing files and fold­ers se­curely. It does this by cre­at­ing a copy of your data in vir­tual mem­ory, se­curely eras­ing the orig­i­nal, and copy­ing the file or folder to a des­ti­na­tion of your choice.

>> To make use of this fea­ture, first open File Ex­plorer and nav­i­gate to the file or folder you wish to move. Rightclick to open the con­text menu, and choose “Eraser > Se­cure Move” [ Im­age D]. Eraser au­to­mat­i­cally opens a prompt ask­ing you to se­lect the tar­get des­ti­na­tion, such as a USB drive. Nav­i­gate to this and click “OK.” Eraser man­ages the copy process and se­curely re­moves data in the usual way.

>> By de­fault, Eraser over­writes drives with one pass of pseudo-ran­dom data. If this isn’t suf­fi­cient to abate your para­noia, ac­cess Eraser’s set­tings, and choose a more se­cure method from the drop-down menu un­der “De­fault drive era­sure method.” 7 SE­CURELY ERASE RE­CY­CLE BIN If there’s con­tent on your PC that you’ve deleted pre­vi­ously, fol­low the steps out­lined above to erase free space on your hard drive. If, how­ever, the files and fold­ers you want to re­move are still in your Re­cy­cle Bin, Eraser can se­curely move these in place. Sim­ply right-click the Re­cy­cle Bin and choose “Erase.” If you’ve pre­vi­ously en­abled the plau­si­ble deniability fea­ture, note that Era­sure doesn’t place de­coy files in the Re­cy­cle Bin. Be sure to use Eraser di­rectly on sen­si­tive data in fu­ture if you want to avoid scru­tiny of your hard drive.

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