Eicon Networks S92 Manuel d'utilisateur télécharger pdf (Page 40)

YuChakTinMichael‘sGIACGCFWProjectAssignment

Page 40

inspectiontechnology.Aformofdynamicpacketfiltering,statefulinspectionworks

atthenetworklayerandtrackseachconnectiontraversingallinterfacesofthefirewall

tomakesuretheyarevalid.

Statefulinspectionis“superior”asitexaminesnotonlythepacketheaderbutalsothe

packetcontents.Suchinspectionisdoneallthewayuptotheapplicationlayer,

makingitpossibleforfilteringdecisionstobemadebasedoncontextthathasbeen

establishedbypriorpassedpackets.Asameasureagainstportscanning,stateful

inspectionfirewallsalwayscloseoffportsuntilconnectiontothespecificportis

requested.

ForthisprojectIusedFW1version4.0forx86,whichisnotcurrentbutiswhatI

haveonhand.ItrunsonWindowsNTServer4.0.Tomakethisfirewallsystemtruly

secure,thethingsthatneedtobedoneare:

n HardeningNTitself –applyallthelatestservicepacks,patchesandfixes;and

disablealltheunnecessaryservicesandcomponents.

n SecuringFW1–again,applyallthelatestpatchesandfixesforversion4.

Hardeni ngtheNTInstallation

AccordingtoCERT’sNTconfigurationguidelines,therearetwotypesofpatches

fromMicrosoft:ServicePacksandHotfixes.Servicepacksareforpatchingawide

rangeofvulnerabilitiesandbugs,whilehotfixesarereleasedmorefrequentlythan

servicepacksandareforpatchingmorespecificproblems

5

.

Keepinmindthough,thatservicepacksarecumulative,meaningweonlyneedto

installthelatestServicePack.Forfixes,however,weneedtodeterminewhatto

install(aswewon’tneedallofthem).ServicePackmustbeinstalledbeforethe

Hotfixes.

Wemayaccessalltheseservicepacksandupdatesfromacentrallocation:

http://www.microsoft.com/ntserver/nts/downloads/default.asp#RecommendedUpdates.

5

http://www.cert.org/tech_tips/win_configuration_guidelines.html

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Eicon Networks S92 Manuel d'utilisateur Page 40