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Figure C-1: DEP and ASLR status shown in Process ExplorerFigure C-2: Security cookie (/GS) reference in the function prologue and epilogue(IDA Pro)182 Appendix C
To check the system-wide configurations of Linux systems as wellas ELF binaries and processes for different exploit mitigation techniques,you can use my checksec.sh 9 script.C.2 RELRORELRO is a generic exploit mitigation technique to harden thedata sections of an ELF 10 binary or process. ELF is a common fileformat for executables and libraries that is used by a variety of UNIXlikesystems, including Linux, Solaris, and BSD. RELRO has twodifferent modes:Partial RELRO• Compiler command line: gcc -Wl,-z,relro.• The ELF sections are reordered so that the ELF internal datasections (.got, .dtors, etc.) precede the program’s data sections(.data and .bss).• Non-PLT GOT is read-only.• PLT-dependent GOT is still writeable.Full RELRO• Compiler command line: gcc -Wl,-z,relro,-z,now.• Supports all the features of Partial RELRO.• Bonus: The entire GOT is (re)mapped as read-only.Both Partial and Full RELRO reorder the ELF internal data sectionsto protect them from being overwritten in the event of a bufferoverflow in the program’s data sections (.data and .bss), but only FullRELRO mitigates the popular technique of modifying a GOT entry toget control over the program execution flow (see Section A.4).To demonstrate the RELRO mitigation technique, I made up twosimple test cases. I used Debian Linux 6.0 as a platform.Test Case 1: Partial RELROThe test program in Listing C-1 takes a memory address (see line 6)and tries to write the value 0x41414141 at that address (see line 8).01 #include 0203 int04 main (int argc, char *argv[])05 {06 size_t *p = (size_t *)strtol (argv[1], NULL, 16);07Mitigation 183
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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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msgbb_datapdatabb_rptrdb_basedatabu
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8180 /*8181 * Null terminate the st
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26736 /*26737 * SIOC[GS]TUNPARAM ap
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19165 * are also rejected as they i
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01 #include 02 #include 03 #include
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fffffe8000f7e4b0 unix:die+da ()ffff
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zero pagenot mappedzero pageis mapp
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gaining full control over EIP/RIP a
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112 return 1;113 }114115 printf ("O
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solaris$ isainfo -b64I then compile
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ip_output+0x10()ip_wput+0x37()putne
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Notes1. The source code of OpenSola
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4.1 Vulnerability DiscoveryTo find
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167 if (current_track + 1 > fourxm-
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Step 1: Find a Sample 4X Movie File
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Next, I modified the values of trac
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Table 4-2: List of the Assembler In
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63 #elif defined (HAVE_MEMALIGN)64
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linux$ gdb -q ./ffmpeg_g(gdb) run -
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(UINT_MAX / sizeof(AudioTrack) - 1)
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7ebe000-b7ec0000 r--p 0015c000 08:0
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5Browse and You’re OwnedSunday, A
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{SWI.ClassId_q.ClassId clsid = new
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27 except KeyboardInterrupt:28 prin
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Figure 5-4: Defining a breakpoint a
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Figure 5-7: User-controlled argumen
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Next, I tried to retrieve the size
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05 06 arg = String(232, "A") + Stri
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iDefense VCPnotifiedVulnerability d
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6.1 Vulnerability DiscoveryI used t
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Step 3: Check the Device Security S
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Below, the elements of the MajorFun
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At address .text:00010748, a pointe
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[..][..]//// Current stack location
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The transfer type is specified usin
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If the requested IOCTL code matches
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Figure 6-5: Graph view of the vulne
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.text:00010DBA push 1 ; _DWORD.text
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99 // .text:00010DEF cmp dword ptr
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nt!RtlpBreakWithStatusInstruction:8
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After I gained control over EIP, I
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7A Bug Older Than 4.4BSDSaturday, M
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Here are some examples:Source code
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1094 return (ENXIO);1095 if (t != t
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4. The assumed address of l_open()
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osx$ cat /Library/Logs/panic.logSat
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Back on the Linux host, I started t
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0x35574c, the value is used to calc
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48 define search_memloc49 set $max_
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As the debugger output shows, the E
Page 145: ApplenotifiedApple asks formore det
Page 148 and 149: I performed the following steps whe
Page 150 and 151: I then began fuzzing files of the A
Page 152 and 153: Figure 8-1: Playing the unmodifiedA
Page 154 and 155: • Line 40 copies the current proc
Page 156 and 157: As the debugger output shows, media
Page 158 and 159: The manipulated byte (0xff) that ca
Page 160 and 161: (gdb) x/12x 0x1301bfc0x1301bfc: 0x0
Page 162 and 163: ApplenotifiedApple confirmsthe vuln
Page 164 and 165: Every function of a process that is
Page 166 and 167: eip 0x43434343 0x43434343eflags 0x1
Page 168 and 169: The access violation is caused when
Page 170 and 171: is less than 12. If it is, the stri
Page 172 and 173: The program in Listing A-4 calls th
Page 174 and 175: 0x080483f3 : mov DWORD PTR [esp+0x4
Page 177 and 178: BDebuggingThis appendix contains in
Page 179 and 180: Information CommandsCommandDescript
Page 181 and 182: Information CommandsCommandrkbu add
Page 183 and 184: Figure B-3: Configuration settings
Page 185 and 186: Figure B-6: Attaching the kernel de
Page 187 and 188: Other CommandsCommandset disassembl
Page 189 and 190: linux# pwd/home/tk/gdb-292/srclinux
Page 191: Notes1. See the Solaris Modular Deb
Page 194 and 195: The many mitigation techniques coul
Page 198 and 199: 08 p[0] = 0x41414141;09 printf (“
Page 200 and 201: ConclusionIn case of a buffer overf
Page 202 and 203: zonecfg:wwwzone> set autoboot=truez
Page 204 and 205: Notes1. See Rob King, “New Leopar
Page 206 and 207: COMRaider, 72coordinated disclosure
Page 208 and 209: Rreadelf, 161RELRO, 67-69, 183-186r
Page 210: A Bug Hunter’s Diary is set in Ne
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