數(shù)據(jù)庫安全外文翻譯

1、共共9頁第 頁DatabasSeecurity“WhydoIneedtosecuremydatabaseserver?NoonecanaccessititsinaDMZprotedctbeythefirewall!”Thisisoftentheresponsewhenitisrecommendedthatsuchdevicesareincludedwithinasecurityhealthcheck.Infact,databasesecurityisparamountindefendinganorganizationsinformation,asitmaybeindirectlyexposed

2、toawideraudiencethanrealized.Thisisthefirstoftwoarticlesthatwillexaminedatabasesecurity.Inthisarticlewewilldiscussgeneraldatabasesecurityconceptsandcommonproblems.InthenextarticlewewillfocusonspecificMicrosoftSQaLndOraclesecurityconcerns.Databasesecurityhasbecomeahottopicinrecenttimes.Withmoreandmor

3、epeoplebecomingincreasinglyconcernedwithcomputersecurity,wearefindingthatfirewallsandWebserversarebeingsecuredmorethanever(thoughthisdoesnotmeanthattherearenotstillalargenumberofinsecurenetworksoutthere).Assuch,thefocusisexpandingtoconsidertechnologiessuchasdatabaseswithamorecriticaleye.ommonensesec

4、urityeforewediscusstheissuesrelatintodatabasesecurityitisprudenttohigh-lightthenecessitytosecuretheunderlyingoperatingsystemandsupportingtechnologies.Itisnotworthspendingalotofeffortsecuringadatabaseifavanillaoperatingsystemisfailingtoprovideasecurebasisforthehardeningofthedata-base.Therearealargenu

5、mberofexcellentdocumentsinthepublicdomaindetailingmeasuresthatshouldbeemployedwheninstallingvariousoperatingsystems.OnecommonproblemthatisoftenencounteredistheexistenceofadatabaseonthesameserverasawebserverhostinganInternet(orIntranet)facingapplication.Whilstthismaysavethecostofpurchasingaseparatese

6、rver,itdoesseriouslyaffectthesecurityofthesolution.Wherethisisidentified,itisoftenthecasethatthedatabaseisopenlyconnectedtotheInternet.OnerecentexampleIcanrecallisanApacheWebserverservinganorganizationsInterneotffering,withanOracledatabaseavailableontheInternetonport152W1he.ninvestigatingthisissuefu

7、rtheritwasdiscoveredthataccesstotheOracleserverwasnotprotected(includinglackofpasswords),whichallowedtheservertobestopped.ThedatabasewasnotrequiredfromanInternetfacingperspective,buttheuseofdefaultsettingsandcarelesssecuritymeasuresrenderedtheservervulnerable.Thepointsmentionedabovearenotstrictlydat

8、abaseissues,andcouldbeclassifiedasarchitecturalandfirewallprotectionissuesalso,butultimatelyitisthedatabasethatiscompromised.Securityconsiderationshavetobemadefromallpartsofapublicfacingnet-work.Youcannotrelyonsomeoneorsomethingelsewithinyourorganizatiopnrotectingyourdatabasefromexposure.Attacktools

9、arenowavailableforexploitingweaknessesinSQLandOracleIcameacrossoneinterestingaspectofdatabasesecurityrecentlywhilecarryingoutasecurityreviewforaclient.Wewereperformingatestagainstanintranetapplication,whichusaedatabasebackend(SQL)tostoreclientdetails.Thseecurityreviewwasproceedingwell,withaccesscont

10、rolsbeingbasedonWindowsauthentication.OnlyauthenticatedWindowsuserswereabletoseedatabelongingtothem.Theapplicationitselfseemedtobehandlinginputrequests,rejectingallattemptstoaccessthedata-basedirectly.Wtheenhappenetdocomeacrossabackupoftheapplicationintheofficeinwhichwewereworking.Thismediacontained

11、abackupoftheSQLdatabase,whichwerestoredontoourlaptop.Allsecuritycontrolswhichwereinplaceoriginallywerenotrestoredwiththedatabaseandwewereabletobrowsethecompletedatabase,withnorestrictionsinplacetoprotectthesensitivedata.Thimsayseemlikeacontrivedwayofcompromisintghesecurityofthesystem,butdoeshighligh

12、tanimportantpoint.Itisoftennotthedirectapproachthatistakentoattackatarget,andultimateltyheendpointisthesame;systemcompromiseA.backupcopyofthdeatabasemaybestoredontheserver,andthusfacilitatesaccesstothedataindirectly.Thereisasimplesolutiontotheproblemidentifiedabove.SQL2000canbeconfiguredtousepasswor

13、dprotectionforbackups.Ifthebackupiscreatedwithpasswordprotection,thispasswordmbuesutsedwhenrestoringthepassword.Thiissaneffectiveanduncomplicatemdethoodfstoppingsimplecaptureofbackupdata.Itdoeshowevermeanthatthepasswordmustberemembered!CuernrttrendsTheraereanumberofcurrenttrendsinITsecurityw,ithanum

14、beorfthesebeinglinkedtodatabasesecurity.Thefocusondatabasesecurityisnowattractingtheattentionoftheattackers.AttacktoolsarenowavailableforexploitingweaknessesinSQLandOracle.Themergenceofthesteoolshasraisedthestakesandwehaveseenfocusedattacksagainstspecificdata-baseportsonserversexposedtotheInternet.O

15、necommonthemerunningthroughthesecurityindustryiosnthefocusapplicationsecuritya,ndinparticularbespokeWebapplications.WithefunctionalityofWebapplicationsbecomingmoreandmorecomplex,itbringsthepotentialformoresecurityweaknessesinbespokeapplicationcode.Inordertofulfillthefunctionalityofapplications,theba

16、ckenddatastoresarecommonlbyeingusedtoformatthecontentofWebpages.Thirsequiremsorecomplexcodingattheapplicationend.Withdevelopersusingdifferentstylesincodedevelopment,someofwhicharenotassecurityconsciousasother,thiscanbethesourceofexploitableerrors.SQLinjectionisonesuchhottopicwithintheITsecurityindus

17、tryatthemoment.Discussionsarenowcommonplaceamongtechnicalsecurityforums,withmoreandmorewaysandmeansofexploitingdatabasescomingtolightallthetime.SQiLnjectionisamisleadingterm,astheconceptappliestootherdatabases,includingOracle,DB2andSybase.hatisnectionnectiohssimplythemethodocommunicationithadatabase

18、usingcodeorcommandssentviaamethodorapplicationnotintendedbythedeveloper.ThemostcommonformofthisisfoundinWebapplications.Anyuserinputthatishandledbytheapplicationisacommonsourceofattack.OnesimpleexamploefmishandlingofuserinputishighlightedinFigure1.Manyofyouwillhaveseenthiscommonerrormessagewhenacces

19、singwebsites,andoftenindicatesthattheuserinputhasnotbeencorrectlyhandled.Ongettingthistypeoferror,anattackerwillfocusinwithmorespecificinputstrings.Specificsecurity-relatedcodingtechniquesshouldbeaddedtocodingstandardinusewithinyourorganization.Thedamagedonebythistypeofvulnerabilitycanbefarreaching,

20、thoughthisdependsonthelevelofprivilegestheapplicationhasinrelationtothedatabase.Iftheapplicationisaccessingdatawithfulladministratortypeprivileges,thenmaliciouslyruncommandswillalsopickupthisleveloafccess,andsystemcompromiseisinevitable.Againthisissueisanalogoustooperatingsystemsecurityprinciples,wh

21、ereprogramshouldonlyberunwiththeminimumofpermissionsthatisrequired.Ifnormaluseraccessisacceptable,thenapplythisrestriction.AgaintheproblemofSQLsecuritiysnottotallyadatabaseissue.Specificdatabasecommandorrequestsshouldnotbeallowtoedpassthroughtheapplicationlayer.Thiscanbepreventedbyemployinga“securec

22、oding”approach.Againthisisveeringoff-topic,butitisworthdetailingafewbasicstepsthatshouldbeemployed.Thefirststepinsecuringanyapplicationshouldbethevalidationandcontrolofuserinput.Stricttypingshouldbeusedwherepossibletocontrolspecificdata(e.g.ifnumericdataisexpected),andwherestringbaseddataisrequired,

23、specificnonalphanumericcharactersshouldbeprohibitedwherepossible.Wherethiscannotbeperformed,considerationshouldbemadetotryandsubstitutecharacters(foerxampletheuseofsinglequotes,whicharecommonlyusedinSQLcommands).Specificsecurity-relatedcodingtechniquesshouldbeaddedtocodingstandardinusewithinyourorga

24、nization.Ifalldevelopersareusingthesamebaselinestandards,withspecificsecuritymeasures,thiswillreducetheriskofSQLinjectioncompromises.Anothersimplemethodthatcanbeemployedistoremoveallprocedureswithinthedatabasethatarenotrequired.Thisrestrictstheextentthatunwantedorsuperfluousaspectsofthedatabasecould

25、bemaliciouslyused.Thisisanalogoustoremovingunwantedservicesonanoperatingsystem,whichiscommonsecuritypractice.verallnconclusion,mostofthepointshavemadeabovearecommonsensesecurityconcepts,andarenotspecifictodatabases.HoweverallofthesepointsDOapplytodatabasesandifthesebasicsecuritymeasuresareemployed,t

26、hesecurityofyourdatabasewillbegreatlyimproved.ThenextarticleondatabasesecuritywillfocusonspecificSQLandOraclesecurityproblems,withdetailedexamplesandadviceforDBAsanddevelopers.TherearealotofsimilaritiesbetweendatabasesecurityandgeneralITsecurity,withgenericsimplesecuritystepsandmeasuresthatcanbe(and

27、shouldbe)easilyimplementedtodramaticallyimprovesecurity.Whilethesemayseemlikecommonsense,itissurprisinghowmanytimeswehaveseenthatcommonsecuritymeasuresarenotimplementedandsocauseasecurityexposure.UseraccountandpasswordsecurityOneofthebasicfirstprincipalsinITsecuriitsy“makesureyouhaveagoodpassword”.WithinthisstatementIhaveassumedthatapasswordissetinthefirstplace,thoughthisisoftennotthecase.Itouchedoncommonsensesecurityinmylastarticle,butIthinkitisimportanttohighlightthisagain.Aswithopera