HeapViewer

An IDA Pro plugin to examine the heap, focused on exploit development.

Currently supports the glibc malloc implementation (ptmalloc2).

3rd place winner of the 2018 Hex-Rays Plugin Contest

Requirements

• IDA Pro >= 6.9

Tested on

• glibc <= 2.27 (x86, x64)

Features

• Heap tracer (malloc/free/calloc/realloc)
• Malloc chunk info
• Multi-arena info (chunks, top, last-remainder)
• Bins info (fastbins, unsortedbin, smallbins y largebins)
• Tcache info (glibc >= 2.26)
• GraphView for linked lists (bins/tcache)
• Magic utils:
  • Unlink merge info
  • Fake fastbin finder
  • House of force helper
  • Useful libc offsets
  • Calc chunk size (request2size)
  • IO_FILE structs

Install

Just drop the heap_viewer.py file and the heap_viewer folder into IDA's plugin directory.

Because IDA not load libc-dbg symbols in the debug session, is necesary generate a config file before using the plugin. To make this, simply install the libc6-dbg package in the remote linux machine and execute the script utils\get_config.py. Then, paste the content in the heap_viewer\files\config.json file.

get_config.py

$ python get_config.py
[*] config.json:

{
  "libc_offsets": {
    "32": {
      "mp_": 1921312,
      "main_arena": 1922976,
    },
    "64": {
      "mp_": 3883648,
      "main_arena": 3886144,
    }
  },
  "libc_version": "2.27"
}

If you not have the dbg symbols for given libc (ex: CTFs ;D), you can use the get_main_arena tool, and get the main_arena offset for that libc. This is enough so the plugin works correctly. Simply put the main_arena offset in the config.json file.

Examples:

$ ./main_arena_offset
[*] libc version:       2.27
[*] libc file:          /lib/i386-linux-gnu/libc-2.27.so
[*] libc address:       0xf7ceb000
[*] main_arena:         0xf7ec07a0
[*] main_arena offset:  0x1d57a0

$ LD_PRELOAD=./libc_64.so.6 ./main_arena_offset
...

Screenshots

Tracer

Arena & chunk info

Tcache entries

Bins

Bin graph

Fastbin graph

Tcache graph

Find fake fastbin

Unlink merge info

Useful libc offsets

Learning Resources

I'd recommend the following resources alongside this tool for learning heap exploiting.

• shellphish's how2heap

Author

• Daniel García Gutiérrez - @danigargu

Contribuitors 🍺

Special mention to my colleagues soez, wagiro and DiaLluvioso for give me some ideas during the development of the plugin. And of course, the @pwndbg project, from which I picked up some things about heap parsing.

Contributors

Bugs / Feedback / PRs

Any comment, issue or pull request will be highly appreciated :-)