HexRaysCodeXplorer - Hex-Rays Decompiler plugin for easier code navigation. Here are the main features of the plugin: - Automatic type REconstruction for C++ objects. - C-tree graph visualization – a special tree-like structure representing a decompiled routine in c_itemt terms. Useful feature for understanding how the decompiler works. - Navigation through virtual function calls in HexRays Pseudocode window. - Object Explorer – useful interface for navigation through virtual tables (VTBL) structures. In this presentation authors of HexRaysCodeXplorer will be discussing main functionality of the plugin and its application for reverse engineering. The authors will be presenting the algorithm for C++ type REconstruction. Also a special version of HexRaysCodeXplorer (ZeroNigths edition) will be released with new features developed specially for ZeroNights conference. New features will be committed GitHub from the stage

1. HexRaysCodeXplorer:
make object-oriented RE easier
Aleksandr MatrosovEugene Rodionov
@matrosov
@vxradius

2. C++ Code Reconstruction Problems
 Object identification
 Type reconstruction
 Class layout reconstruction




Identify constructors/destructors
Identify class members
Local/global type reconstruction
Associate object with exact method calls
 RTTI reconstruction
 Vftable reconstruction
 Associate vftable object with exact object
 Class hierarchy reconstruction

3. C++ Code Reconstruction: the truth is out there

4. An overview of the Flamer Framework
Vector<Command Executor>
Vector<Consumer>
DB_Query
ClanCmd
FileCollect
Driller
GetConfig
Munch
FileFinder
Mobile
Consumer
Cmd
Consumer
Vector<Task>
IDLER
CmdExec
Sniffer
Lua
Consumer
Vector<DelayedTasks>
Media
Consumer
Euphoria
Share
Supplier
LSS
Sender
Frog
Beetlejuice

5. An overview of the Flamer Framework
Vector<Command Executor>
Vector<Consumer>
DB_Query
ClanCmd
FileCollect
Driller
GetConfig
Munch
FileFinder
Mobile
Consumer
Cmd
Consumer
Vector<Task>
IDLER
CmdExec
Sniffer
Lua
Consumer
Vector<DelayedTasks>
Media
Consumer
Euphoria
Share
Supplier
LSS
Sender
Frog
Beetlejuice

6. An overview of the Flamer Framework
Vector<Command Executor>
Vector<Consumer>
DB_Query
ClanCmd
FileCollect
Driller
GetConfig
Munch
FileFinder
Mobile
Consumer
Cmd
Consumer
Vector<Task>
IDLER
CmdExec
Sniffer
Lua
Consumer
Vector<DelayedTasks>
Media
Consumer
Euphoria
Share
Supplier
LSS
Sender
Frog
Beetlejuice

7. HexRaysCodeXplorer

9. HexRaysCodeXplorer Features
 Hex-Rays decompiler plugin
 The plugin was designed to facilitate static
analysis of:
 object oriented code
 position independent code
 The plugin allows to:
 navigate through decompiled virtual methods
 partially reconstruct object type

10. Hex-Rays Decompiler Plugin SDK
 At the heart of the decompiler lies ctree structure:
 syntax tree structure
 consists of citem_t objects
 there are 9 maturity levels of the ctree structure

11. Hex-Rays Decompiler Plugin SDK
 At the heart of the decompiler lies ctree structure:
 syntax tree structure
 consists of citem_t objects
 there are 9 maturity levels of the ctree structure

12. Hex-Rays Decompiler Plugin SDK
 Type citem_t is a base class for:
 cexpr_t – expression type
 cinsn_t – statement type
citem_t
cexpr_t
cinsn_t
 Expressions have attached type information
 Statements include:
 block, if, for, while, do, switch, return, goto, asm
 Hex-Rays provides iterators for traversing the citem_t
objects within ctree structure:
 ctree_visitor_t
 ctree_parentee_t

13. Hex-Rays Decompiler Plugin SDK
 Type citem_t is a base class for:
 cexpr_t – expression type
 cinsn_t – statement type
citem_t
cexpr_t
cinsn_t
 Expressions have attached type information
 Statements include:
 block, if, for, while, do, switch, return, goto, asm
 Hex-Rays provides iterators for traversing the citem_t
objects within ctree structure:
 ctree_visitor_t
 ctree_parentee_t

14. HexRaysCodeXplorer: Gapz Position Independent Code

15. HexRaysCodeXplorer: Virtual Methods
 The IDA’s “Local Types” is used to represent object type

16. HexRaysCodeXplorer: Virtual Methods
 Hex-Rays decompiler plugin is used to navigate through
the virtual methods

17. HexRaysCodeXplorer: Virtual Methods
 Hex-Rays decompiler plugin is used to navigate through
the virtual methods

18. HexRaysCodeXplorer: Object Type REconstruction
 Hex-Rays’s ctree structure may be used to
partially reconstruct object type based on its
initialization routine (constructor)
 Input:
 pointer to the object instance
 object initialization routine entry point
 Output:
 C structure-like object representation

19. HexRaysCodeXplorer: Object Type REconstruction
 Hex-Rays’s ctree structure may be used to
partially reconstruct object type based on its
initialization routine (constructor)
 Input:
 pointer to the object instance
 object initialization routine entry point
 Output:
 C structure-like object representation

20. HexRaysCodeXplorer: Object Type REconstruction
 citem_t objects to monitor:
 memptr  call (LOBYTE, etc.)
 idx
 memref

21. HexRaysCodeXplorer: Object Type REconstruction
// reference of DWORD at offset 12 in buffer a1
*(DWORD *)(a1 + 12) = 0xEFCDAB89;

22. HexRaysCodeXplorer: Object Type REconstruction
// reference of DWORD at offset 12 in buffer a1
*(DWORD *)(a1 + 12) = 0xEFCDAB89;

23. HexRaysCodeXplorer 1.1 [ZeroNights Edition]
 Type Reconstruction:
 reconstruct type into IDA local types
 bugfixes =)
 ObjectExplorer:
 Auto structures for VTBL
 Click on VTBL and jump to code
 ObjectExplorer hints for VTBL

24. NO TIME for DEMO

27. Thank you for your attention!
Eugene Rodionov
Aleksandr Matrosov
@vxradius
@matrosov