Bug Hunter Diary

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Step 4: Find the User-Controlled Input ValuesNext, I disassembled the binary C:\Program Files\WebEx\WebEx\824\atucfobj.dll with IDA Pro. 8 In IDA, the imagebase of atucfobj.dll was0x10000000. So NewObject() was located at address 0x1000767f (imagebase+ offset of NewObject(): 0x10000000 + 0x767F) in the disassembly (seeFigure 5-6).Figure 5-6: Disassembly of the NewObject() method in IDA ProBefore I started reading the assembly, I had to ensure what functionargument holds the user-controlled string value provided throughthe VBScript in Listing 5-1. Since the argument is a string, I guessedthat my value was being held in the second parameter, lpWideCharStr,shown in IDA. I wanted to be sure, however, so I defined a new breakpointat the NewObject() method and had a look at the arguments in thedebugger (see Section B.2 for a description of the following debuggercommands).As illustrated in Figure 5-7, I defined the new breakpoint at theaddress of NewObject() (0:009> bp 01d5767f), continued the executionof Internet Explorer (0:009> g), and again navigated to the http://www.webex.com/ domain. When the breakpoint was triggered, I inspectedthe value of the second function argument of NewObject() (0:000> ddpoi(esp+8) and 0:000> du poi(esp+8)). As the debugger output shows,the user-controlled data (a wide-character string consisting of 12 As)was indeed passed to the function through the second argument.Finally, I had all information I needed to start auditing themethod for security bugs.78 Chapter 5
Figure 5-7: User-controlled argument of NewObject() after defining a new breakpointStep 5: Reverse Engineer the Object MethodsTo recap, I found an obvious vulnerability that happens while theActiveX control processes the user-supplied string value that getspassed to NewObject(). Figure 5-8 illustrates the code path to reachthe vulnerable function.Figure 5-8: Code path to reach the vulnerable function (created in IDA Pro)Browse and You’re Owned 79
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A Bug Hunter’s Diary. Copyright
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Chapter 3: Escape from the WWW Zone
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B.2 The Windows Debugger (WinDbg) .
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IntroductionWelcome to A Bug Hunter
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1Bug HuntingBug hunting is the proc
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After I’ve found a bug, I want to
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Table 1-1: Debuggers Used in This B
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2Back to the ’90sSunday, October
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16361637 /* clear the SEQ table */1
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If a TiVo file is loaded by VLC, th
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Get the →vulnerableWindows versio
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EIP = 41414141 . . . Mission EIP co
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NoteTo configure Process Explorer t
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See the following excerpt from the
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3. Immunity Debugger is a great Win
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NoteInput/output controls (IOCTLs)
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Page 44 and 45: 8180 /*8181 * Null terminate the st
Page 46 and 47: 26736 /*26737 * SIOC[GS]TUNPARAM ap
Page 48 and 49: 19165 * are also rejected as they i
Page 50 and 51: 01 #include 02 #include 03 #include
Page 52 and 53: fffffe8000f7e4b0 unix:die+da ()ffff
Page 54 and 55: zero pagenot mappedzero pageis mapp
Page 56 and 57: gaining full control over EIP/RIP a
Page 58 and 59: 112 return 1;113 }114115 printf ("O
Page 60 and 61: solaris$ isainfo -b64I then compile
Page 62 and 63: ip_output+0x10()ip_wput+0x37()putne
Page 64 and 65: Notes1. The source code of OpenSola
Page 66 and 67: 4.1 Vulnerability DiscoveryTo find
Page 68 and 69: 167 if (current_track + 1 > fourxm-
Page 71 and 72: Step 1: Find a Sample 4X Movie File
Page 73 and 74: Next, I modified the values of trac
Page 75 and 76: Table 4-2: List of the Assembler In
Page 77 and 78: 63 #elif defined (HAVE_MEMALIGN)64
Page 79 and 80: linux$ gdb -q ./ffmpeg_g(gdb) run -
Page 81 and 82: (UINT_MAX / sizeof(AudioTrack) - 1)
Page 83 and 84: 7ebe000-b7ec0000 r--p 0015c000 08:0
Page 85 and 86: 5Browse and You’re OwnedSunday, A
Page 87 and 88: {SWI.ClassId_q.ClassId clsid = new
Page 89 and 90: 27 except KeyboardInterrupt:28 prin
Page 91: Figure 5-4: Defining a breakpoint a
Page 95 and 96: Next, I tried to retrieve the size
Page 97 and 98: 05 06 arg = String(232, "A") + Stri
Page 99: iDefense VCPnotifiedVulnerability d
Page 102 and 103: 6.1 Vulnerability DiscoveryI used t
Page 104 and 105: Step 3: Check the Device Security S
Page 106 and 107: Below, the elements of the MajorFun
Page 108 and 109: At address .text:00010748, a pointe
Page 110 and 111: [..][..]//// Current stack location
Page 112 and 113: The transfer type is specified usin
Page 114 and 115: If the requested IOCTL code matches
Page 116 and 117: Figure 6-5: Graph view of the vulne
Page 118 and 119: .text:00010DBA push 1 ; _DWORD.text
Page 120 and 121: 99 // .text:00010DEF cmp dword ptr
Page 122 and 123: nt!RtlpBreakWithStatusInstruction:8
Page 124 and 125: After I gained control over EIP, I
Page 127 and 128: 7A Bug Older Than 4.4BSDSaturday, M
Page 129 and 130: Here are some examples:Source code
Page 131 and 132: 1094 return (ENXIO);1095 if (t != t
Page 133 and 134: 4. The assumed address of l_open()
Page 135 and 136: osx$ cat /Library/Logs/panic.logSat
Page 137 and 138: Back on the Linux host, I started t
Page 139 and 140: 0x35574c, the value is used to calc
Page 141 and 142: 48 define search_memloc49 set $max_
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As the debugger output shows, the E
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ApplenotifiedApple asks formore det
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I performed the following steps whe
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I then began fuzzing files of the A
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Figure 8-1: Playing the unmodifiedA
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• Line 40 copies the current proc
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As the debugger output shows, media
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The manipulated byte (0xff) that ca
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(gdb) x/12x 0x1301bfc0x1301bfc: 0x0
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ApplenotifiedApple confirmsthe vuln
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Every function of a process that is
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eip 0x43434343 0x43434343eflags 0x1
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The access violation is caused when
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is less than 12. If it is, the stri
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The program in Listing A-4 calls th
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0x080483f3 : mov DWORD PTR [esp+0x4
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BDebuggingThis appendix contains in
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Information CommandsCommandDescript
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Information CommandsCommandrkbu add
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Figure B-3: Configuration settings
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Figure B-6: Attaching the kernel de
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Other CommandsCommandset disassembl
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linux# pwd/home/tk/gdb-292/srclinux
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Notes1. See the Solaris Modular Deb
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The many mitigation techniques coul
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Figure C-1: DEP and ASLR status sho
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08 p[0] = 0x41414141;09 printf (“
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ConclusionIn case of a buffer overf
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zonecfg:wwwzone> set autoboot=truez
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Notes1. See Rob King, “New Leopar
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COMRaider, 72coordinated disclosure
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Rreadelf, 161RELRO, 67-69, 183-186r
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A Bug Hunter’s Diary is set in Ne
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