计算机专业英语10 网络和计算机安全039Word下载.docx

计算机专业英语10 网络和计算机安全039Word下载.docx

《计算机专业英语10 网络和计算机安全039Word下载.docx》由会员分享，可在线阅读，更多相关《计算机专业英语10 网络和计算机安全039Word下载.docx（12页珍藏版）》请在冰豆网上搜索。

1.SecurityViolationDefinition

Computerornetworksecurityhasbeenviolatedwhenunauthorizedaccessbyanypartyoccurs.

2.WhySecurity?

Computersecurityisrequiredbecausemostorganizationscanbedamagedbyhostilesoftwareorintruders.Theremaybeseveralformsofdamagewhichareobviouslyinterrelated.Theseinclude:

•Damageordestructionofcomputersystems.

•Damageordestructionofinternaldata.

•Lossofsensitiveinformationtohostileparties.

•Useofsensitiveinformationtostealitemsofmonetaryvalue.

•Useofsensitiveinformationagainsttheorganization'

scustomerswhichmayresultinlegalactionbycustomersagainsttheorganizationandlossofcustomers.

•Damagetothereputationofanorganization.

•Monetarydamageduetolossofsensitiveinformation,destructionofdata,hostileuseofsensitivedata,ordamagetotheorganization'

sreputation.

Themethodsusedtoaccomplishtheseunscrupulousobjectivesaremanyandvarieddependingonthecircumstances.Thisguidewillhelpadministratorsunderstandsomeofthesemethodsandexplainsomecountermeasures.

3.SecurityIssues

Computersecuritycanbeverycomplexandmaybeveryconfusingtomanypeople.Itcanevenbeacontroversialsubject.Networkadministratorsliketobelievethattheirnetworkissecureandthosewhobreakintonetworksmayliketobelievethattheycanbreakintoanynetwork.Ibelievethatoverconfidenceplaysanimportantroleinallowingnetworkstobeintrudedupon.Therearemanyfallaciesthatnetworkadministratorsmayfallvictimto.Thesefallaciesmayallowadministratorstowrongfullybelievethattheirnetworkismoresecurethanitreallyis.

Thisguidewillattempttoclarifymanyissuesrelatedtosecuritybydoingthefollowing:

•Helpyoudeterminewhatyouareprotecting.

•Breakcomputersecurityintocategories.

•Explainsecuritytermsandmethods.

•Pointoutsomecommonfallaciesthatmayallowadministratorstobeoverconfident.

•Categorizemanycommonattacksagainstnetworksandcomputers.

•Explainsomeattackmethods.

•Describetoolsthatcanbeusedtohelpmakeanetworkmoresecure.

4.SecurityInterdependence

Therearemanydifferentaspectstocomputerandnetworksecurity.Thesedifferentareasofcomputersecurityareinterdependentoneachotherinorderforanetworktobesecure.Ifoneormoreareasofcomputersecurityareignored,thentheentiresecurityintegrityoftheorganization'

snetworkmaybecompromised.Aclearexampleofthisisintheareaofcomputervirusorwormprotection.Computervirusprotectionprogramscanonlyfilterknownvirusesorworms.Therearevirusesorwormsthatarenotyetrecognizedasvirusprogramsimmediatelyaftertheirrelease.Thebestwaytomakeunrecognizedvirusorwormprogramslesseffectiveisbyquicklyremovingthevulnerabilitiesthattheyuse.Someofthesevulnerabilitiesareoperatingsystemandapplicationprogramerrors.Whensecuritypatchesarecreatedforsoftware,theyshouldbequicklyapplied.Inthiswaythevulnerabilitytovirusesisminimizedbutnoteliminated.Thereareotherstepswhichmayfurtherreducethisvulnerability,butitcanneverbecompletelyeliminated.

5.SecurityLimitationsandApplications

Ifyouarereadingthisdocumentandarethinkingthatyoucangetalltheinformationrequiredtomakeyournetworkcompletelysecure,thenyouaresadlymistaken.Inmanyways,computersecurityisalmostastatisticalgame.Youcanreducebutnoteliminatethechancethatyoumaybepenetratedbyanintruderorvirus.Thisismainlyforonereason:

Noonecaneverknowallthesoftwarevulnerabilitiesofallsoftwareusedonasystem.

Thisiswhyeventhosewhoconsiderthemselveshackerswillsaythatthenumberonecomputersecuritythreatisthelackofqualityintheapplicationsandoperatingsystems.

Thebottomlinehereisthatunlessyoucanremovealltheapplicationandoperatingsystemproblemsthatallowvirusesandintruderstopenetratenetworks,youcanneversecureyournetwork.Additionallytheusersonyournetworkarepotentiallyagreatersecurityriskthananyprograms.Obviouslyremovingallvulnerabilitiesisimpossibleandwillnotsecureyournetworkagainstusererrors.Ihaveevenconsideredthepossibilitythatanoperatingsystemwithoutanetworkinterfacecanbecompletelysecure,buteventhiscannotbeguaranteed.UnknownvirusesorTrojanprogramscancreepinwithapplicationsonCDsorfloppies.Thishasbeenknowntohappen.Althoughanattackermaynotbeabletogetdatafromthesystem,theycandamageordestroydata.

6.LayeredSecurity

Thefactthatcompletesecurityisimpossibleisthereasonsecurityexpertsrecommend"

layeredsecurity"

.Theideaistohavemultiplewaysofpreventinganintrusiontodecreasethechancethatintrusionswillbesuccessful.Forexample,youshouldhavevirusprotectiononyourclientcomputers.Tohelplayerthissecurityyoushouldalsofiltervirusesatyouremailserver.Tohelpevenmore,youshouldblockthemostdangeroustypesofemailattachmentstopreventunrecognizedvirusesandotherhostilesoftwarefromenteringyournetwork.Anothergooddefenselayerwouldalsoincludeeducatingyourusersaboutviruses,howtheyspread,andhowtoavoidthem.

Hackers

Therearemanydocumentsthatattempttodefinethetermhacker.Ibelievethatthetermhackerisaconnotativeterm.Thismeansthatitismoredefinedbypeople'

sbeliefsratherthanbyadictionary.Somebelievethatahackerisaveryskilledcomputerperson.Othersbelievethathackersarethosethatperformunauthorizedbreakintocomputersystems.Themediaandmanysourceshavecausedmanyuninformedpeopletobelievethatahackerisathreattocomputerandnetworksecuritywhilethisisnotthecase.Ahackerisnomorelikelytobreakthelawthananyoneelse.Iusethemoreaccuratedescriptiveterm,"

intruder"

todescribethosewhointrudeintonetworksorsystemswithoutauthorization.

8.PhysicalSecurity

Thisguidewillnottalkaboutphysicalcomputersecuritybeyondthisparagraph.Yourorganizationshouldbeawarehowphysicallysecureeveryaspectofitsnetworkisbecauseifanintrudergetsphysicalaccess,theycangetyourdata.Besurethatyourorganizationproperlysecureslocationsandconsiderthefollowing:

•Servers-Containyourdataandinformationabouthowtoaccessthatdata.

•Workstations-Maycontainsomesensitivedataandcanbeusedtoattackothercomputers.

•Routers,switches,bridges,hubsandanyothernetworkequipmentmaybeusedasanaccesspointtoyournetwork.

•Networkwiringandmediaandwheretheypassthroughmaybeusedtoaccessyournetworkorplaceawirelessaccesspointtoyournetwork.

•Externalmediawhichmaybeusedbetweenorganizationalsitesortoothersitestheorganizationdoesbusinesswith.

•Locationsofstaffwhomayhaveinformationthatahostilepartycanuse.

•Someemployeesmaytakedatahomeormaytakelaptopshomeoruselaptopsontheinternetfromhomethenbringthemtowork.Anyinformationontheselaptopsshouldbeconsideredtobeatriskandtheselaptopsshouldbesecureaccordingtoproperpolicywhenconnectedexternallyonthenetwork.

9.SomeTerms

Thisparagraphdescribessomecommonlyusedcomputersecurityterms.

•Protocol-Welldefinedspecificationallowingcomputercommunication.

•Confidentiality-Informationisavailableonlytopeoplewithrightfulaccess.

•Integrity-Informationcanonlybechangedbyauthorizedpersonnel.Thereceiverofthemessageshouldbeabletotellthemessagewasnotmodified.

•Availability-Informationisavailabletoonlythosewhoneedit.

•Verification-nonrepudiation-Thereisproofthatthesendersentthemessage

•Authentification-Thereceiverofthemessageshouldbeabletobesureoftheoriginofthemessage.Requiresadigitalsignature（Onewayhash,publickeyalgorithm,andsymmetricalgorithm）orapublickeyalgorithm.

•Spyware-Acomputerprogramwhosepurposeistospyonyourinternetactivitiesusuallyformarketingpurposesandusuallydonebyashadycorporateentity.

•Malware-Acomputerprogramwithsomeevilintent.Itmayonthesurfacehaveagoodoru