Reverse Engineering 101

Reversing 101 - Yasin Sürer (2013 - Gazi University, The Department of Computer Engineering Graduate - Ankara/Turkey)

Transcript

1. Reverse Engineering 101 Yasin SÜRER http://twitter.com/yasinsurer
2. Jargon A zero-day(or zero-hour or day zero) attack or threat is an attack that exploits a previously unknown vulnerability in a computer application. An exploit is a piece of software, a chunk of data, or sequence of commands that takes advantage of a bug A shellcode is a small piece of code used as the payload in the exploitation of a software vulnerability A rootkit is a stealthy type of software, often malicious, designed to hide the existence of certain processes or programs from normal methods of detection and enable continued privileged access to a computer.
3. Attacker Mindset Vulnerability Research Find the vulnerability, and developing weaponized-exploits. Exploit Development Zero-day attack uses advanced-exploitationtechnique Understanding undocumented system functions malware authors; Rootkit, worm, keylogger, spyware etc.
4. Defensive Perspective Patch and Vulnerability Analysis Developing signatures against zero-day threats for IDS/IPS appliance Binary Code Analysis Finding new zero-day vulnerabilities to take advantage on defensive perspective Advanced Exploit Development Penetration Test and Vulnerability assesment. Malware Analysis Anti-Virus, Anti-Spyware and Digital Forensics companies
5. Real-World Crime Example May 2008 in New York for the Dave & Busters case May 2008 in Massachusetts for the TJ Maxx case August 2009 in New Jersey in connection with the Heartland Payment case.
7. State-Sponsored Attack Example The group obtained a sponsor who paid them 2000 RMB ($325) per month Their sponsor is likely the People's Liberation Army (PLA) Tan Dailin attacks on US Department of Defense in May and June 2006 GinWui Rootkit (Manipulate Service, Start and Kill Process etc.) iDefense says,35 zero-day Microsoft Office Exploit
8. State-Sponsored Attack Example
9. Advanced Persistent Threat
10. ‘’We do not call those types of threats as Advanced Persistent Threat since they use widely known, old-school tactics’’ Microsoft
11. US Department of Defense Offensive Contractors
23. Reverse Engineering
24. What is Reverse Engineering ? Static Analysis or Reversing Static program analysis is the analysis of computer software that is performed without actually executing programs Dynamic Analysis or Reversing Dynamic program analysis is the analysis of computer softwarethat is performed by executing programs on a real or virtual processor.
25. x86 Architecture & Assembly
26. Arithmetic Instructions mov eax, 5 ; eax=5 mov ebx, 3 ; ebx=3 add eax, ebx ; eax = eax + ebx sub ebx, 2 ; ebx = ebx -2
27. Accessing Memory cmp eax, 2 ; compare eax with 2 je label ; if(eax == 2) ja label ; if(eax > 2) jb label ; if(eax < 2) jbe label ; if(eax <= 2) jne label ; if(eax != 2) jmp label ; jump label
28. Function Calls call function ; store return addr on the stack ; and jump to function! func: push esi ; save esi … pop esi ; restore esi ret ; read return addr from the stack ; and jump to it.
29. Modern Compiler Native Language Intermediate Representation Low-level Intermediate representation x86 Assembly
30. Binary Reverse Engineering How the compiler works and to translate it into machine code Understanding operating system structures Understanding executable (PE/ELF) file formats We need to think like the compiler, but in reverse!
31. Toolbag
32. Reverser Toolbag (1) IDA Disassembler from Hex-Rays IDA is a disassembler for computer software which generates assembly language source code from machine-executable code OllyDbg is Free Debugger OllyDbg is an x86 debugger that emphasizes binary code analysis, which is useful when source code is not available Windbg from Microsoft It can be used to debug user mode applications, drivers, and the operating system itself in kernel mode.
33. Reverser Toolbag (2) Virtual Machines (Virtualbox, VMWare, Hyper-V) A virtual machine (VM) is a software implemented abstraction of the underlying hardware, which is presented to the application layer of the system. Packet Sniffers (Wireshark, tcpdump) The sniffer captures packets, if needed, decodes the packet's raw data, showing the values of various fields in the packet Sysinternals Suite technical resources and utilities to manage, diagnose, troubleshoot, and monitor a Microsoft Windows environment.
34. PEiD
35. IDA Pro
36. IDA Pro (2)
37. IDA Pro (3)
38. IDA Pro (4)
39. OllyDbg
40. OllyDbg (2)
41. Windbg
42. Windbg (2)
43. Intro to Windbg • r: display current register content • t: trace-step (until call) • pt: single-step (until-ret) • g: process run (go!) • .hh: help command. (for example .hh t) • lm: list modules
44. Sysinternal: Process Explorer
45. Sysinternal: Process Monitor
46. Sysinternal: Autoruns
47. ImpREC
48. LordPE
49. Anti-Reverse Engineering Anti-Debugging, the implementation of one or more techniques within computer code that ‘’hinders attempts’’ at reverse engineering or debugging a target process Anti-Dumping, describes the process of taking an executable that has been protected and after the executable has been decrypted into memory Code obfuscation is the deliberate act of creating obfuscated code, i.e. source or machine code that is difficult for humans to understand. Executable compression is any means of compressing an executable file and combining the compressed data with decompression code into a single executable
50. Executable Compression (Packed Executables)
51. Packed Executable
52. Packed Executable
53. Packed Executable
54. Packed Executable
55. Packed Executable
56. Anti-Debugging
57. Anti-Debugging
58. Anti-Debugging
59. Anti-Debugging
60. Anti-Debugging
61. Anti-Debugging
62. FATMAL (Real-World Example)
63. FATMAL
64. Loader
65. Loader
66. Payload InstallBot()
67. Payload
68. Payload
69. Payload
70. Payload
71. Payload
72. Who could be behind the FATMAL attack?
75. Memory Analysis - Sality -
76. Memory Analysis
77. Memory Analysis
78. Memory Analysis
79. Memory Analysis
80. Memory Analysis
81. Resources
83. Analysis of Mobile Threats
84. Mobile Market 49% 19% 13% 11% 5% 3% Android iPhone BlackBerry Windows Phone Symbian Other
85. Mobile Threats 79 19 0,3 0,7 0,3 0,7 Android Symbian Windows Mobile iPhone BlackBerry J2ME
86. Mobile Threats 66,1 0,7 1 2,7 0,3 5,6 7 11,2 3,7 Trojan Downloader Spy Adware Backdoor Hacktool Monitoring Riskware Spyware Application
87. Android Android is a Linux-based operating system, runs on custom Linux. Google I/O statshot, 900 million Android devices activated Google play hits 600.000 application, 20 billion total installs. Manufacturers; Samsung, HTC, Asus, Amazon, Sony, Toshiba, Acer…
88. Android Apps Android Market APK/ZIP Metadata (manifest, images) Dex File (classes.dex)
89. Android Architecture
90. Geinimi
91. Geinimi
92. Geinimi
93. Geinimi
94. Geinimi
95. Geinimi
96. Geinimi
97. 5 years of silence…
98. The ProGuard tool shrinks, optimizes, and obfuscates your code by removing unused code and renaming classes, fields, and methods with semantically obscure names. DexGuardis our specialized optimizer and obfuscator for Android. Create apps that are faster, more compact, and more difficult to crack.
99. Obfuscation
100. Obfuscation
101. Obfuscation
102. Modifying The bytecode
103. Android Application Dalvik VM! Activity Thread Zygote Activity Manager Launcher
104. Modifying the byte-code JNI Native Code Dalvik bytecode Modified!
105. Processor
107. so what…
108. Malware writers is getting ready to implement x86 techniques for Android.
109. Questions…