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Overview

Overview. Firefox exploit Code injection using buggy javascript interpeter Javascript code exploiting the bug The bug in C++ The bug in assembly code Instrumentation: Finding values Daikon: Finding invariants LiveShield: Enforcing invariants. Remote Code Execution Exploit. html. Load.

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Overview

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  1. Overview • Firefox exploit • Code injection using buggy javascript interpeter • Javascript code exploiting the bug • The bug in C++ • The bug in assembly code • Instrumentation: Finding values • Daikon: Finding invariants • LiveShield: Enforcing invariants DARPA AC MIT Site Visit

  2. Remote Code Execution Exploit html Load Java script From: http://aviv.raffon.net/2005/12/11/MozillaUnderestimateVulnerabilityYetAgainPlusOldVulnerabilityNewExploit.aspx April 10, 2007 DARPA AC MIT Site Visit DARPA AC MIT Site Visit 2

  3. JavaScript Exploit Code // spray payload memory = new Array(); for (i=0;i<heapBlocks;i++) // Insert x86 instructions for calling shell code. memory[i]= …; // Invoke injected code InstallTrigger.install.call(0x9800000, "a", "a"); April 10, 2007 DARPA AC MIT Site Visit DARPA AC MIT Site Visit 3

  4. JavaScript Interpreter (C++ code) // getting C++ object from JavaScript object nsIDOMInstallTriggerGlobal *nativeThis = (nsIDOMInstallTriggerGlobal*)JS_GetPrivate(cx, obj); // bug: doesn’t check the type of nativeThis nativeThis->UpdateEnabled(globalObject, XPI_WHITELIST, &enabled); // exploit point April 10, 2007 DARPA AC MIT Site Visit DARPA AC MIT Site Visit 4

  5. Disassembled Code nativeThis->UpdateEnabled(globalObject, XPI_WHITELIST, &enabled); // exploit point push ecx push 1 push dword ptr [ebp-10h] push ebx call dword ptr [eax+0Ch] // ptr[eax+0Ch] is the method address April 10, 2007 DARPA AC MIT Site Visit DARPA AC MIT Site Visit 5

  6. Overview • Firefox exploit • Instrumentation: Finding values • Register and memory values, jumps, calls, and returns • Daikon: Finding invariants • LiveShield: Enforcing invariants DARPA AC MIT Site Visit

  7. Instrumentation April 10, 2007 • To find invariants without source code or debug symbol access • Captures important values • Finding exploit root causes is challenging • Currently manually select locations for instrumentation • Memory firewall (Determina) may help to locate DARPA AC MIT Site Visit DARPA AC MIT Site Visit 7

  8. Binary Variable Examples • Binary variable: a variable in machine (binary) code • Name: instruction address and register name • Value : value of register or reference mov dword ptr [ebp-34h],esi mov eax,dword ptr [ebx] push ecx April 10, 2007 DARPA AC MIT Site Visit DARPA AC MIT Site Visit 8

  9. Binary Variable Examples • Binary variable: a variable in machine (binary) code • Name: instruction address and register name • Value : value of register or reference mov dword ptr [ebp-34h],esi mov eax,dword ptr [ebx] push ecx April 10, 2007 DARPA AC MIT Site Visit DARPA AC MIT Site Visit 9

  10. x86 Instrumentation Output • Binary variable: a variable in machine (binary) code • Name: instruction address and register name • Value : value of register or reference mov dword ptr [ebp-34h],esi mov eax,dword ptr [ebx] push ecx instrumentation xpinstal.dll:0xa111 BV esi 0x00000000 xpinstal.dll:0xa114 BV ebx 0x01f13bcc xpinstal.dll:0xa114 BV [ebx] 0x6005c6d8 xpinstal.dll:0xa116 BV ecx 0x0012ecf4 April 10, 2007 DARPA AC MIT Site Visit DARPA AC MIT Site Visit 10

  11. Output for Firefox Normal Runs call dwordptr [eax+0Ch] xpinstal.dll:0xa11d BV [eax+0Ch] 0x6004592d […] xpinstal.dll:0xa11d BV [eax+0Ch] 0x6004592d […] xpinstal.dll:0xa11d BV [eax+0Ch] 0x6004592d […] April 10, 2007 DARPA AC MIT Site Visit DARPA AC MIT Site Visit 11

  12. Normal VS Exploit Runs • Normal run xpinstal.dll:0xa11d BV [eax+0Ch] 0x6004592d • Exploit run xpinstal.dll:0xa11d BV [eax+0Ch] 0x1200002c April 10, 2007 DARPA AC MIT Site Visit DARPA AC MIT Site Visit 12

  13. Overview • Firefox exploit • Instrumentation: Finding values • Daikon: Finding invariants • Grouping values into basic blocks • Grouping basic blocks into program points • Finding invariants among variables in a program point • LiveShield: Enforcing invariants DARPA AC MIT Site Visit

  14. Basic Block Basic Block Basic Block Grouping values into basic blocks Thread Address (dll+offset) opcode (BV=Binary Variable) • ... • 1588 xpinstal.dll:0x5ebe BV esp 0x0012df20 • 1588 xpinstal.dll:0x5ebe ICALL ret xpinstal.dll:0x5ec1 • xpinstal.dll:0x5ecf BV esp 0x0012df1c • 1588 xpinstal.dll:0x5ecf BV [4+esp] 0x1e78e98 • ... • 1588 xpinstal.dll:0x5ed9 BV [0+esp] 0x60045ec1 • xpinstal.dll:0x5ed9 RET to xpinstal.dll:0x5ec1 • xpinstal.dll:0x5ec1 BV eax 0x00000002 • ... DARPA AC MIT Site Visit

  15. Grouping basic blocks into program points • You might need variables from previous basic-blocks to find the right invariant • For example: • The right invariant might be: • The size of the buffer is less than 256: Some.dll:0x1bb1d mov eax, … char* p = …; while (*p) { … } Some.dll:0x1bccc mov …, [eax] eax@Some.dll:0x1bccc - eax@Some.dll:0x1bb1d < 256 DARPA AC MIT Site Visit

  16. Algorithm to create Daikon input • Partition the basic blocks into functions • Build a control-flow-graph for each function • Calculate dominators • The program point of each basic block includes the binary-variables in its dominators DARPA AC MIT Site Visit

  17. Invariant for Firefox Exploit Buggy Code xpinstal.dll:0xa11d call [eax+0Ch] xpinstal.dll:0xa120 cmp … Invariant [eax+0Ch]@xpinstal.dll:0xa11d == 0x6004592d DARPA AC MIT Site Visit

  18. Overview • Firefox exploit • Instrumentation: Finding values • Daikon: Finding invariants • LiveShield: Enforcing invariants • Code in C that is woven into the application when loaded into the code cache • Determina’s product • Distributed and managed in the central controller DARPA AC MIT Site Visit

  19. LiveShield for Firefox Exploit <file name="xpinstal.dll"/> <patch offset="0xa116"> <function type="detector" name="ff_detector"/> <function type="protector" name="ff_protector“ return="0xa120"/> </patch> LiveShield hotp_exec_status_t ff_detector(const hotp_context_t *hotp_context) { if (POI(EAX+0xC) != 0x6004592d) return HOTP_EXEC_EXPLOIT_DETECTED | HOTP_EXEC_LOG_EVENT; return HOTP_EXEC_EXPLOIT_NOT_DETECTED; } LiveShield hotp_exec_status_t ff_protector(hotp_context_t *hotp_context) { UNREFERENCED_PARAMETER(hotp_context); return HOTP_EXEC_CHANGE_CONTROL_FLOW | HOTP_EXEC_LOG_EVENT; } LiveShield DARPA AC MIT Site Visit

  20. Demo • Run the FireFox exploit • Turn on a previously generated LiveShield • Run the FireFox exploit again on a different community workstation DARPA AC MIT Site Visit

  21. Firefox Exploits DARPA AC MIT Site Visit

  22. IE Exploits DARPA AC MIT Site Visit

  23. IE exploit – Illegal function call • Exactly like the FireFox exploit • Same fix: skip the call <body onLoad="window();"> jscript.dll:75c5f429 call [ecx+0x8] DARPA AC MIT Site Visit

  24. IE exploit – buffer overflow <object type="////…/////AAAAAAAAAAAAAAAA"/> • String is checked for proper buffer size • Then '/' is changed into '_/_' • Invariant: • Fix: 761240CE lea eax, [ebp+0x104] ... 761240E1 mov [eax], 5Fh 761240E4 inc eax ... eax<=(ebp+0x104)+242) if (eax>(ebp+0x104)+242) eax = (ebp+0x104)+242 DARPA AC MIT Site Visit

  25. Current Protection Process • For example: Vista bug ms06-17 • Determina creates a LiveShield • Knowledge and labor intensive, tedious • Dec 20 : Microsoft informed • Mar 27 : attack in the wild • Apr 3: Microsoft develops a patch • Patch is deployed in the community DARPA AC MIT Site Visit

  26. Application Community Protection Process • Application Community learns • Exploit deployed by blackhats • Exploit automatically recognized • Patch automatically generated • 0-day exploit → 0-day patch DARPA AC MIT Site Visit

  27. Summary • Instrumentation: Finding values • Register and memory values, jumps, calls, and returns • Daikon: Finding invariants • Grouping values into program points • LiveShield: Enforcing invariants • Code in C that is woven into the application • Real exploits: 4 in Firefox, 5 in IE DARPA AC MIT Site Visit

  28. End • Any questions? DARPA AC MIT Site Visit

  29. Eventhandlers – buffer overflow <foo onclick=foo onclick=foo … > 748D94CF mov ecx, [eax+45Ch] eax+0x45C<=93 if (eax+0x45C>93) eax = 93 DARPA AC MIT Site Visit

  30. isComponentInstalled – buffer overflow obj.isComponentInstalled("…") lstrcatA(&subkey_buf, clsid); strlen(clsid)<=93 if (eax+0x45C>93) eax = 93 DARPA AC MIT Site Visit

  31. IE VML – buffer overflow <html xmlns:v="urn:schemas-microsoft-com:vml"> <head> <title>IE VML crash</title> <style> v\:* { behavior: url(#default#VML); } </style> </head> <body> <v:rect style="width:20pt;height:20pt" fillcolor="red"> <v:fill method="AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"/> </v:rect> </body> </html> DARPA AC MIT Site Visit

  32. Strechbelt – Denial of Service <img src="1000x1000.png" width="41943034" height="41943034"> if (width > MAX_WIDTH) width = MAX_WIDTH; if (height > MAX_HEIGHT) height = MAX_HEIGHT; DARPA AC MIT Site Visit

  33. 2218 false positives, out of 41360, which is 5.36% BB-xpinstal.dll_0xbe86-InFunction-xpinstal.dll_0x19818::: xpinstal.dll_0xbe86__0_esp__xpinstal.dll_0xbe86 > xpinstal.dll_0xbe86_esp_xpinstal.dll_0xbe86 xpinstal.dll_0xbe86__0_esp__xpinstal.dll_0xbe86 < xpinstal.dll_0xbe86__0_esp__xpinstal.dll_0xbe87 xpinstal.dll_0xbe86__0_esp__xpinstal.dll_0xbe86 > xpinstal.dll_0xbe86_esp_xpinstal.dll_0xbe87 xpinstal.dll_0xbe86_esp_xpinstal.dll_0xbe86 < xpinstal.dll_0xbe86__0_esp__xpinstal.dll_0xbe87 xpinstal.dll_0xbe86_esp_xpinstal.dll_0xbe86 - xpinstal.dll_0xbe86_esp_xpinstal.dll_0xbe87 + 4 == 0 xpinstal.dll_0xbe86__0_esp__xpinstal.dll_0xbe87 > xpinstal.dll_0xbe86_esp_xpinstal.dll_0xbe87 At ppt BB-xpinstal.dll_0xa10b-InFunction-xpinstal.dll_0x1b9f6:::, Invariant 'xpinstal.dll_0xa10b__12_eax__xpinstal.dll_0xa11d one of { 301989932, 1610897709 }' invalidated by sample xpinstal.dll_0xa10b__12_eax__xpinstal.dll_0xa11d=301989932: at line 13720 in file ff_exploit.dtrace.gz DARPA AC MIT Site Visit

  34. Application Communities MIT CSAIL, Determina

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