https://github.com/elfmaster/dsym_obfuscate
Obfuscates dynamic symbol table
https://github.com/elfmaster/dsym_obfuscate
Last synced: 4 days ago
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Obfuscates dynamic symbol table
- Host: GitHub
- URL: https://github.com/elfmaster/dsym_obfuscate
- Owner: elfmaster
- Created: 2018-12-18T01:20:56.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2019-01-10T05:25:59.000Z (over 6 years ago)
- Last Synced: 2024-11-12T07:38:33.594Z (6 months ago)
- Language: C
- Size: 225 KB
- Stars: 134
- Watchers: 11
- Forks: 26
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
- awesome-hacking-lists - elfmaster/dsym_obfuscate - Obfuscates dynamic symbol table (C)
README
# dsym_obfuscate
Obfuscates dynamic symbol table by removing .dynstr, and replacing it at runtime.
Currently only works on binaries linked only to libc.so (More work to be accomplished)
Bypasses symbol versioning by marking the DT_VERNEED d_tag as a DT_DEBUG, and sets the
DT_VERNEEDNUM d_val to 0.
Currently only works on non PIE executable's. This can easily be fixed.
# Build
```
git clone https://github.com/elfmaster/libelfmaster
cd libelfmaster
make
sudo make install
cd ~/dsym_obfuscate
make
```
# Test
```
elfmaster@dreamcity:~/git/dsym_obfuscate$ nm -D test
U fopen
w __gmon_start__
U __libc_start_main
U pause
U puts
U strtok
elfmaster@dreamcity:~/git/dsym_obfuscate$ ./dsymobf ./test
backing up dynstr
Loaded basename: libc.so.6
Copying over: libc.so.6 to index 1
Injecting constructor.o into ./test
Commiting changes to ./test
elfmaster@dreamcity:~/git/dsym_obfuscate$ nm -D test
U
U
U
U
w __gmon_start__
U __libc_start_main
elfmaster@dreamcity:~/git/dsym_obfuscate$ ./test
Hi
^C
```
# Further work
Get this working on PIE binaries, and binaries that are linked to libraries
other than libc.so.
Currently we just backup the dynamic symbol table, but in practice you would
want to encrypt it with a stream cypher, back it up, and then decrypt it
before restoring at runtime.