Eicon Networks S92 Instrukcja Użytkownika Pobierz pdf (Strona 195)

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

Page 195

DoSattack

TheDoSattackthatIwilluseisaSmurfattack.AccordingtoSymantec,Smurfattack

isaformofDoSthatusesping:

“In thecaseofaSmurfDoSattack,theping'spacketreturnIPaddressisforgedwith

theIPofthetargetedmachine. ThepingisissuedtotheentireI Pbroadcastaddress.

Thiscauseseverymachinetorespondtotheboguspingpacketsandreplytothe

targetedmachine,whichfloodsit.ThisiscalledaSmurfattackbecausetheDoStool

usedtoperformtheattackiscalledSmurf.”

69

Asdescribedby pentics.net,

“Therearetwopartieswhoarehurt bythisattack...  theintermediary(broadcast)

deviceslet'scallthem"amplifiers",andthespoofedaddresstarget,orthe"victim".

Thevictimisthetargetofalargeamountoftrafficthattheamplifiersgenerate.”70

Sincewehave50compromisedDSLsystemsatourdisposal,anattackofa

reasonablestrengthcanbelaunched.Theroleofthesecompromisedsystemswillbe

discussedshortly.

TheAmplifiers

Whocanactasamplifier?

Basically,anynetworkwithroutersacceptingIPdirectedbroadcastandhosts

acceptingICMPpacketscanbeusedasamplifiers.

Howdowelocatetheseamplifiers?

69

http://www.symantec.com/avcenter/venc/data/smurf.dos.attack.html

70

http://www.pentics.net/denialofservice/whitepapers/smurf.cgi

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