Eicon Networks S92 Manual de usuario descargar pdf (Pagina 191)

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

Page 191

Sincewejusttalkedaboutthedefaultports,onethingwecan try istoexplore

vulnerabilitiesrelatedtoFW1’sports.AsearchonCERTreturnsonesuch

vulnerability.Thisvulnerabilityinvolvesport259 andisrelatedtoFW1’sRDP

protocol:

“ByaddingafakedRDPheadertotypicalUDPtraffic,anycontentcan bepassedto

port259onanyhostoneithersideofthedevice.”

61

So,howdowelaunchanattackbasedonthisinformation?Thebestthingtodoisto

lookatthe“Proofofconceptcode”availableat

http://www.insidesecurity.de/fw1_rdp_poc.html.ThesourcecodeisavailableinC

language.Bycompilingourownattackprogramusingthesecodes,suchattackcanbe

launched.Keepinmindthough,thatthisvulnerabilityisfoundonly onFW1version

4.1. Thereisnoevidencethatidenticalvulnerabilityexistsinversion4.0.

ForGIACadministratortoworkonthisissue,itissuggestedthatthefollowing

workaroundssuppliedbyinsideSECURITYbefollowed:

“

Commentline2646ofbase.def(accept_fw1_rdp;) 

DeactivateimpliedrulesintheCheckPointpolicyeditor(andbuildyourownrules

formanagementconnections).

BlockUDPtraffictoport259onyourperimeterrouter.

”

62

Attacking–theTrojanroute:

Thisattackallowsustotakecontrolof FW1.

Wealreadyknowfromour“websitevisit”whatprotocolsareallowedinGIAC’s

securityarchitecture.RememberwetalkedaboutsecondaryDNSserverandzone

transfer?FW14.x’sdefaultpolicysettingdoesallowtrafficthatheadstowardsTCP

port53 topass.Sincemanyadministratorssimplyleavethisoptionasis,whatwecan

dothenistouseNSLOOKUP oranyothermeantoinitiateazonetransferagainstthe

61

http://www.kb.cert.org/vuls/id/310295

62

http://issrv1.insidesecurity.de/fw1_rdp.html

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Eicon Networks S92 Manual de usuario Pagina 191