CryKeX - Linux Memory Cryptographic Keys Extractor
- Application Independable
- Process Wrapping
- Process Injection
- Unix - should work on any Unix-based OS
- BASH - the whole script
- root privileges (optional)
- AES and RSA keys only
- Fails most of the time for Firefox browser
- Won't work for disk encryption (LUKS) and PGP/GPG
- Needs proper user privileges and memory authorizations
How it works
Some work has been already published regarding the subject of cryptograhic keys security within DRAM. Basically, we need to find something that looks like a key (entropic and specific length) and then confirm its nature by analyzing the memory structure around it (C data types).
The idea is to dump live memory of a process and use those techniques in order to find probable keys since, memory mapping doesn't change. Thanks-fully, tools exist for that purpose.
The script is not only capable of injecting into already running processes, but also wrapping new ones, by launching them separately and injecting shortly afterwards. This makes it capable of dumping keys from almost any process/binary on the system.
Of course, accessing a memory is limited by kernel, which means that you will still require privileges for a process.
Linux disk ecnryption (LUKS) uses anti-forensic technique in order to mitigate such issue, however, extracting keys from a whole memory is still possible.
Firefox browser uses somehow similar memory management, thus seems not to be affected.
Same goes for PGP/GPG.
An interactive example for OpenSSL AES keys:
sudo apt install gdb aeskeyfind rsakeyfind || echo 'have you heard about source compiling?'
Enter a password twice, then some text and before terminating:
openssl aes-128-ecb -nosalt -out testAES.enc
Finally, press Ctrl+D 3 times and check the result.
OpenSSL RSA keys:
When prompted for passphrase:
openssl genrsa -des3 -out testRSA.pem 2048
Let's extract keys from SSH:
openssl rsa -noout -text -in testRSA.pem
echo 'Ciphers firstname.lastname@example.org' >> /etc/ssh/sshd_config
TrueCrypt/VeraCrypt is also affected: Select "veracrypt" file in VeraCrypt, mount with password "pass" and:
echo 'cipher AES-256-CBC' >> /etc/openvpn/server.conf
sudo CryKeX.sh openvpn
Chromium-based browsers (thanks Google):
sudo CryKeX.sh veracrypt
Despite Firefox not being explicitly affected, Tor Browser Bundle is still susceptible due to tunneling:
As said, you can also wrap processes:
apt install libssl-dev
gcc -lcrypto cipher.c -o cipher