Presentation on theme: "Securing Gateways Identifying/Defending E-Mail Attacks A. Padgett Peterson, P.E., CISSP Corporate Information Protection Lockheed Martin Corporation Orlando,"— Presentation transcript:
Securing Gateways Identifying/Defending Attacks A. Padgett Peterson, P.E., CISSP Corporate Information Protection Lockheed Martin Corporation Orlando, Florida Las Vegas, 26 July, 2000
26 July 2000appbh002 The Problem In recent months the most serious problems have been from the “Mass Mailer” viruses May take many forms –Word Documents: Melissa –Excel spreadsheets: Papa –VBS files: Loveletter –Script files: KAK All have common roots Are other vectors but less common
26 July 2000appbh003 What makes MassMailers easy
26 July 2000appbh004 Mass Mailers From a corporate/agency standpoint, the really disruptive mechanism are those which broadcast using global address lists (GAL) –potential for thousands of messages –50,000 Melissa seen –200,000 LoveLetter
26 July 2000appbh005 Mass Mailers Thusfar.EXE files are constrained to local access e.g. PrettyPark uses.WAB - has no access to GAL All attacks using GAL are VB based (VBA/VBS/ActiveX)
26 July 2000appbh006 Mass Mailing
26 July 2000appbh007 Looking Sdrawkcab Early vendor told that inclusion of CreateObject in VBS was not a good idea Ignored as usual Russian New Year attack demonstrated capability of embedded scripting Patch issued for RNY WORD/EXCEL. Required 32 Mb download. Ignored PowerPoint.
26 July 2000appbh008 Looking Sdrawkcab - Dec 1997 Outlook added HTML capability –discovering exactly which HTML was like pulling teeth
26 July 2000appbh009 Whazzat ? Image is on remote site Experiment #17, HTML generation test This is a test of HTML response capability If you see more than this message text please let me know Padgett
26 July 2000appbh0010 July 00 - Surprise asp The Office HTML Script vulnerability, allows malicious script code on a web page to reference an Excel 2000 or PowerPoint file in such a way as to cause a remotely hosted file to be saved to a visiting user's hard drive.
26 July 2000appbh0011 Since Then (over 50 Melissas now) etc, etc, etc
26 July 2000appbh0012 What is the common factor ? ALL use CreateObject Are other possible constructs –GetObject (must preexist) –CreateTextObject (using executable ASCII) –GetTextObject –and one more we’ll mention later but not many
26 July 2000appbh0013 Gateway Factor “Block all Scripting” –something about a baby and a bath ? “Block all executables” –care to be a bit more specific: ??_ AD? ASP BAS BAT BIN CDR CHM CMD COM CPL CRT CSC DEV DL? DO? EXE GMS GZ? HLP HT? IM? INI INS ISP JS? MD? MPP MPT MS? OBD OBT OCX OLE OV? PCD POT PP? RTF SCR SCT SHS SMM SYSVB? VS? VXD WBK WPD WS? XL? XML XTP
26 July 2000appbh0014 More Appropriate Allow only permitted extensions Block anything with fab four This re-establishes sandbox –but allows “safe” scripting & VBS
26 July 2000appbh0015 At Desktop Vendor has 8 Mb patch (2 Mb 2000) Affects many elements Does seem to work well with today’s problems, but what about tomorrow ? –Executable written to TEMP directory prior to screen popup exploit already being discussed
26 July 2000appbh0016 At Desktop Best answer probably Integrity Manager/Behavior blocker –no updates required unless new mechanism discovered doesn’t happen very often If network application tries to write to disk, or execute local file, ask first. –Mail, Browser, FTP,...
26 July 2000appbh0017 That other construct CLSID –essentially a call to an internal element –generally one marked “safe for scripting” –and shouldn’t be –may allow creation/writes without “CreateObject” –method used by BubbleBoy/KAK –shouldn’t be in a script anyway
26 July 2000appbh0018 Conclusions Gateways –filters need to be developed that are both specific and granular –need to be able to apply/reconfigure immediately (vendors often lag by several hours) library of special filters needs to be developed commitment from gateway for immediate action specific line of authority to direct filters consided “approved” attachments rather than bad
26 July 2000appbh0019 Conclusions II Gateways –can use multiple products - is a good idea re: scanners –choose defensible points and ones that can be reconfigured quickly. Desktop –Integrity Management/Behavior Blockers may be more appropriate slow updates very large numbers
26 July 2000appbh0020 Thank you Questions ? A. Padgett Peterson, P.E., CISSP