>When decoded, "%0A%0D" translates to <CR><LF>; something that should NEVER exist in a URL. Why NEVER? If you referring to cross site scripting or HTTP Response Splitting attack or Cache poisoning That is matter of server app to filter request data its not made for (i.e. sanitize request data). I saw web apps where you could have %0A%0D directly in url as parameter just to add line to posted comment(all other tags been filtered). >Ain't the HTTP Filter Just The Kewlest Ever? Yes it is cool...but as ISA server itself advise patterns checking might slow down your ISA. I believe its is due to search method coded for this pattern matching. IMHO It is just for temporary/small blocking rules rather than for building bigger http exploits blocking signature system. Some fast regex checking in http header would be nice :-). ________________________________ From: Jim Harrison [mailto:Jim@xxxxxxxxxxxx] Sent: Thursday, January 06, 2005 5:18 AM To: [ISAserver.org Discussion List] Subject: [isalist] Ain't the HTTP Filter Just The Kewlest Ever?!? http://www.ISAserver.org I was wandering through my ISA logs (I have no life; I admit it) and I discovered a crappy little trick Fandango is using to insert ads into your browser (Steve; you reading?): http://www.fandango.com/eyeblaster/addineyeV2.html?strHTML=%3Cscript%3E% 0D%0A%0A%3C%21--%0Avar%20gfEbInIframe%3Dfalse%3B%0Avar%20gEbAd%20%3D%20n ew%20Object%28%29%3B%0AgEbAd.nFlightID%20%3D%2061803%3B%0A//Remote%20ser vers%0AgEbAd.playRS%20%3D%20new%20Object%28%29%3B%0AgEbAd.playRS.strNUrl %20%3D%20%22http%3A//ad.doubleclick.net/imp%3Bv1%3Bi%3B12979394%3B0-0%3B 0%3B5755652%3B468%7C60%3B8301289%7C8319185%7C1%3B%3Bcs%3Dy%253fhttp%3A// m3.doubleclick.net%22%3B%0A//Interactions%0AgEbAd.interactions%20%3D%20n ew%20Object%28%29%3B%0AgEbAd.interactions%5B%22_eyeblaster%22%5D%20%3D%2 0%22ebN%3Dhttp%3A//ad.doubleclick.net/click%253Bh%3Dv3%7C31f4%7C2%7C0%7C %252a%7Cm%253B12979394%253B0-0%253B0%253B5755652%253B1-468%7C60%253B8301 289%7C8319185%7C1%253B%253B%257Esscs%253D%253fhttp%3A//m3.doubleclick.ne t%3B%22%3B%0A//--%3E%3C/script%3E%3Cscript%20src%3D%27http%3A//ds.servin g-sys.com/BurstingScript/ebServing.js%27%3E%3C/script%3E <http://www.fandango.com/eyeblaster/addineyeV2.html?strHTML=%3Cscript%3E %0D%0A%0A%3C%21--%0Avar%20gfEbInIframe%3Dfalse%3B%0Avar%20gEbAd%20%3D%20 new%20Object%28%29%3B%0AgEbAd.nFlightID%20%3D%2061803%3B%0A//Remote%20se rvers%0AgEbAd.playRS%20%3D%20new%20Object%28%29%3B%0AgEbAd.playRS.strNUr l%20%3D%20%22http%3A//ad.doubleclick.net/imp%3Bv1%3Bi%3B12979394%3B0-0%3 B0%3B5755652%3B468%7C60%3B8301289%7C8319185%7C1%3B%3Bcs%3Dy%253fhttp%3A/ /m3.doubleclick.net%22%3B%0A//Interactions%0AgEbAd.interactions%20%3D%20 new%20Objec> ..luckily, since I run my own blocking scripts, the HTTP Filter saw the "%0D%0A" sequence and said "hell NO!" "12217 0x80 Blocked by the HTTP Security filter: URL contains sequences which are disallowed" ..ok; you may ask - what does "%0D%0A " mean to me? When decoded, "%0A%0D" translates to <CR><LF>; something that should NEVER exist in a URL. There are also other characters that are normally associated with a technique called "script injection"; a method whereby the sender tricks your browser or server into doing something you'd really rather it didn't. Those characters are shown as "script" and "/script" surrounded by "%3C" and "%3E"; "<" and ">", respectively. This is an older (pretty useless, too) script injection method. They also try to obfuscate (developer term used to obfuscate the meaning of the conversation) other characters that might trigger filtering mechanisms, such as: "http%3A//" (translates to http://). Since none of my current scripts include the "%3Cscript" sequence, I'll create another blocking definition and post it. Needless to say, Fandango just made the top of my sh1tlist... Jim Harrison MCP(NT4, W2K), A+, Network+, PCG http://isaserver.org/Jim_Harrison/ http://isatools.org Read the help / books / articles! ------------------------------------------------------ List Archives: http://www.webelists.com/cgi/lyris.pl?enter=isalist ISA Server Newsletter: http://www.isaserver.org/pages/newsletter.asp ISA Server FAQ: http://www.isaserver.org/pages/larticle.asp?type=FAQ ------------------------------------------------------ Other Internet Software Marketing Sites: World of Windows Networking: http://www.windowsnetworking.com Leading Network Software Directory: http://www.serverfiles.com No.1 Exchange Server Resource Site: http://www.msexchange.org Windows Security Resource Site: http://www.windowsecurity.com/ Network Security Library: http://www.secinf.net/ Windows 2000/NT Fax Solutions: http://www.ntfaxfaq.com ------------------------------------------------------ You are currently subscribed to this ISAserver.org Discussion List as: davidf@xxxxxxx To unsubscribe visit http://www.webelists.com/cgi/lyris.pl?enter=isalist Report abuse to listadmin@xxxxxxxxxxxxx All mail to and from this domain is GFI-scanned. 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