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niklasb / libc-database

Build a database of libc offsets to simplify exploitation
https://libc.rip/
MIT License
1.72k stars 192 forks source link
ctf ctf-tools libc offsets pwn

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Web interface

libc-database now has a web service and frontend. Visit https://libc.rip/ to try it out! Read https://github.com/niklasb/libc-database/tree/master/searchengine if you are interested in the API.

Building a libc offset database

If you're getting errors, please check the "Requirements" section below.

Fetch the desired libc categories and extract the symbol offsets. It will not download anything twice, so you can also use it to update your database:

$ ./get  # List categories
$ ./get ubuntu debian  # Download Ubuntu's and Debian's libc, old default behavior
$ ./get all  # Download all categories. Can take a while!

You can also add a custom libc to your database.

$ ./add /usr/lib/libc-2.21.so

Find all the libc's in the database that have the given names at the given addresses. Only the last 12 bits are checked because randomization usually works on page size level.

$ ./find printf 260 puts f30
archive-glibc (libc6_2.19-10ubuntu2_i386)

Find a libc from the leaked return address into __libc_start_main.

$ ./find __libc_start_main_ret a83
ubuntu-trusty-i386-libc6 (libc6_2.19-0ubuntu6.6_i386)
archive-eglibc (libc6_2.19-0ubuntu6_i386)
ubuntu-utopic-i386-libc6 (libc6_2.19-10ubuntu2.3_i386)
archive-glibc (libc6_2.19-10ubuntu2_i386)
archive-glibc (libc6_2.19-15ubuntu2_i386)

Dump some useful offsets, given a libc ID. You can also provide your own names to dump.

$ ./dump libc6_2.19-0ubuntu6.6_i386
offset___libc_start_main_ret = 0x19a83
offset_system = 0x00040190
offset_dup2 = 0x000db590
offset_recv = 0x000ed2d0
offset_str_bin_sh = 0x160a24

Check whether a library is already in the database.

$ ./identify /usr/lib/libc.so.6
local-f706181f06104ef6c7008c066290ea47aa4a82c5

Or find a libc using a hash (currently BuildID, MD5, SHA1 and SHA256 is implemented):

$ ./identify bid=ebeabf5f7039f53748e996fc976b4da2d486a626
libc6_2.17-93ubuntu4_i386
$ ./identify md5=af7c40da33c685d67cdb166bd6ab7ac0
libc6_2.17-93ubuntu4_i386
$ ./identify sha1=9054f5cb7969056b6816b1e2572f2506370940c4
libc6_2.17-93ubuntu4_i386
$ ./identify sha256=8dc102c06c50512d1e5142ce93a6faf4ec8b6f5d9e33d2e1b45311aef683d9b2
libc6_2.17-93ubuntu4_i386

Download the whole libs corresponding to a libc ID.

$ ./download libc6_2.23-0ubuntu10_amd64
Getting libc6_2.23-0ubuntu10_amd64
    -> Location: http://security.ubuntu.com/ubuntu/pool/main/g/glibc/libc6_2.23-0ubuntu10_amd64.deb
    -> Downloading package
    -> Extracting package
    -> Package saved to libs/libc6_2.23-0ubuntu10_amd64
$ ls libs/libc6_2.23-0ubuntu10_amd64
ld-2.23.so ... libc.so.6 ... libpthread.so.0 ...

Requirements

General

To run these scripts, you will need following command on your PATH:

Debian-based (Ubuntu, Debian, Kali Linux, ParrotSec)

RPM-based (category 'rpm')

CentOS-based

In addition to the RPM-Based requirements, you will need:

Pacman-based

APK Based

Launchpad-based

In addition to the Debian-based requirements, you will need:

Install everything

To install everything on Debian 10, run these commands:

apt-get update
apt-get install -y \
  binutils file \
  wget \
  rpm2cpio cpio \
  zstd jq