I forgot the password to my bitcoin backup and would like to brute-force decrypt it.
I have been given this information;
"The manual backup files are encrypted using your chosen backup password. You can use OpenSSL to decrypt:
openssl enc -d -aes-256-cbc -a -in <filename>"
Unfortunately, I don't have much experience doing this and all I can do it get it in terminal asking for the password. Can anybody give me instructions on how to brute-force decrypt a file using OpenSSL?
n.b. The password was quite simple, using only letters and perhaps one number.
... all I can do it get it in terminal asking for the password.
You need to add -passin pass:XXX options, where XXX is the password you want to try.
There's more options for -passin, see PASS PHRASE ARGUMENTS for openssl(1) command.
You will also need to understand the -k and -K options to openssl enc.
Can anybody give me instructions on how to brute-force decrypt a file using OpenSSL?
Run something like this in a loop:
# Build your list of candidates
PASSWORDS=...
for PASSWORD in $PASSWORDS; do
openssl enc -d -aes-256-cbc -a -in <filename> -passin pass:$PASSWORD
RET=$?
if [ $RET -eq 0 ]; then
echo "Candidate password: $PASSWORD"
fi
done
openssl enc returns 0 on success, non-zero otherwise. Note: you will get false positives because AES/CBC can only determine if "decryption works" based on getting the padding right. If the file decrypts but is not recovered, then remove that candidate password.
Authenticated encryption would fix the ambiguity, but you would have needed to encrypt with AES/CCM, AES/GCM, AES/EAX etc.
If you want to try on your own there is now a bruteforcing tool that will do it very efficiently, called bruteforce-salted-openssl. Note that the digest used back in the days by openssl was md5 (rather than sha256 today), so you would have to specify the digest (-m md5)
Related
I would like to decrypt a text using a 32 characters key and a salt from command line in my MacOS. I have encrypted it in Windows using a program. But, whenever I try to decrypt it from command line I couldn't and get an error.
echo -n PuYNZO+SLqFo6g97gxKr2uAPRUph/sZgaJ3T5YIBPIc= | openssl enc -d -a -aes-256-cbc -K TheTestKeyUsedIs32CharactersLong -S 53616c7455736564 -iv 0 -p
hex string is too short, padding with zero bytes to length
hex string is too short, padding with zero bytes to length
non-hex digit
invalid hex key value
When I try to encrypt
100836
in MacOS it gives me completely different string.
U2FsdGVkX19TYWx0VXNlZA4AWDWo5nzi8p5pYyAeUMg=
using following command:
openssl enc -aes-256-cbc -a -S 53616c7455736564 -iter 5 -k TheTestKeyUsedIs32CharactersLong -in input.txt -out openssl_output.txt
From the application I am using in Windows
100836
is converting into
PuYNZO+SLqFo6g97gxKr2uAPRUph/sZgaJ3T5YIBPIc=
My salt text is SaltUsed
My 32 bit character key is TheTestKeyUsedIs32CharactersLong
Input is PuYNZO+SLqFo6g97gxKr2uAPRUph/sZgaJ3T5YIBPIc=
Should be decrypted in 100836
But, result is completely unexpected.
I have also tried a java program to decrypt it but there I was getting other strings so thought to correct it with command line first and then will jump into the code.
I also tried the key in hex digits but still the response was incorrect and was not as expected.
#Wasif and I spent some time debugging in chat and in the end believe it's most likely a compatbility issue between OpenSSL 1.1.1.d on Windows and OpenSSL 1.1.1.b on macOS.
We went through a number of tests and permutations, using (Key, IV) tuples in hex, using passwords, with and without salts, and ultimately our testing came down to a simple check.
Using openssl enc -a -aes-256-cbc -pass pass:MYPASSWORD -p -in input.txt on Windows we got:
salt=E70092FEBA619144
key=29631452F8C259DFE6FD8E9372EC4B20392395F36B7A0B11769CEBEA987E90A0
iv =93BF2E94462A43B23EF585C0F4B3F1A8
U2FsdGVkX1/nAJL+umGRRGi3ybIPFXf7qrgov7SyXnI=
Using openssl aes-256-cbc -d -a -pass pass:MYPASSWORD -in cipherText.txt (which contains 'U2FsdGVkX1/nAJL+umGRRGi3ybIPFXf7qrgov7SyXnI=' on the Mac we got:
4593573484:error:06FFF064:digital envelope routines:CRYPTO_internal:bad decrypt
Despite this simple test failing, the Mac and Windows boxes successfully encrypted and decrypted locally.
Weird, but this looks like version incompatibility.
Try specifying the digest alorithm:
Default digest has changed between different versions.
See
How to resolve the "EVP_DecryptFInal_ex: bad decrypt" during file decryption
Im trying to decrypt a text, which was encrypted with AES-256-ECB with the given key. To decrypt, Im using the same version of the openssl which was used for encryption (OpenSSL 1.1.1d 10 Sep 2019).
String to decrypt: VAWawVAWawxiyH20dI+t5NPAY9w== (inside file.txt)
Key: 461a966faef244e4808d6b2b8e928d01 (inside key.txt)
I tried those commands:
cat file.txt | base64 -d > file2.txt
openssl enc -AES-256-ECB -d -in file2.txt -out answer.txt --kfile key.txt
And im getting: bad magic number. Whats the problem?
openssl enc will normally use a password to derive a key. So it is the derived key that is used to decrypt the file. The derivation process requires a "salt", and openssl enc during encryption stores that salt at the beginning of the file along with a "magic number" to identify it. If the magic number is missing (usually because the file wasn't encrypted by openssl enc or because the password based key derivation derivation method wasn't used) then you get this error.
The -kfile option tells OpenSSL to read the password from a file and then derive the key from it. Probably want you intended was to not use password derivation at all, but to use the explicit key. In which case you need to use the -K option and supply the key on the command line using hex.
I am trying to encrypt using RC4 using openssl. I can match results with online cipher tools only with key as hex but not as plaintext.
Using password option with plaintext - DOES NOT MATCH.
# echo -ne "stackoverflow" | openssl rc4 -pass pass:"rc4cipher" -nopad -nosalt | xxd -p
Result : 8189898ec30bd96a81bca0e293
Getting the symmetric key for the password
#echo -ne "stackoverflow" | openssl rc4 -pass pass:"rc4cipher" -nopad -nosalt -p
key=1E8B649064CC6657312EE7346ED410A4
With hexa key for the above password (-k option) - MATCHES.
echo -ne "stackoverflow" | openssl rc4 -K "1E8B649064CC6657312EE7346ED410A4" -nopad -nosalt | xxd -p
Result :8189898ec30bd96a81bca0e293
I can match my result with online tools by using key as hex but not as plain text.
Can someone help please me with the option to use with openssl ?
Thanks,
Ak
Keys should consist of random binary data. They should not consist of text. If you need to perform password based encryption you need to use a password hash or, more precisely, a Password Based Key Derivation Function to turn the password into a key. Common PBKDF's are bcrypt, scrypt, PBKDF2 and Argon2.
And this is what OpenSSL (command line) does underneath: it uses a weak, OpenSSL proprietary algorithm called EVP_BytesToKey. This is basically only compatible with OpenSSL implementations or compatibility libs.
Most online tools (which you should never use to validate any implementation in the end) simply convert the text to binary using character-encoding such as UTF-8, Windows-1252 or any other - usually unspecified - encoding. This is not secure; it's as braindead as most click-bait encryption tools found online.
I had a question where I asked about dumping a tar'ed folder to an SSH target. This is useful when backing up servers that have no enough disk space. The solution I got and it works, is this:
tar czv <stuff to backup> | ssh user#server.com 'cat > /home/user/backupfolder/backup.tar.gz'
But the problem now is that I usually pipe tar to openssl to encrypt my packages with
tar zcpf / | openssl des3 -salt | dd of=backup.des3
My question: Now I wanna do the same, but with dumping the resulting archive directly into the SSH target, as given in that answered question but with OpenSSL encryption.
I tried the following:
tar zcpf / | openssl des3 -salt | ssh user#backupserver.com 'cat > /some/dir/backup.tar.gz'
This causes a race between the password asked by OpenSSL and the password asked by ssh, which results in a problem making OpenSSL refuse the input password when repeating it.
Note: Using a public key for logging in without a password isn't considered a useful solution for my case. (EDIT: Also passing the password to OpenSSL is not a solution).
Is there a way to do this without problems? I see the solution as to have OpenSSL ask me about the password, and then ssh ask me about the password, with no racing between them.
Thanks in advance. If you require any additional details, please ask.
You can pass the password with pass argument to encryption.
This should prevent seeking of encryption password later in time and then clash with the password prompt for SSH.
tar zcpf / | openssl des3 -salt -pass pass:1234 | ssh user#backupserver.com 'cat > /some/dir/backup.tar.gz'
EDIT:
This answer does not suit the OP's requirement. The edit made later mentions that passing password as argument is not acceptable.
So I finally managed to create my own bash script that will do the job and fix the problem. Remember that the script has to be run as root if you want to backup the root folder. You can make it fancier by adding root checker at the beginning of the script.
#!/bin/bash
dirToBackup=/
targetDir=/path/to/encrypted/backup/file.des3
sshuser=user
sshserver=myserver.com
read -s -p "Enter Encryption Password: " mypassword1
printf "\n"
read -s -p "Repeat Encryption Password: " mypassword2
printf "\n"
#make sure the passwords match
if [ "$mypassword1" != "$mypassword2" ]
then
echo "Passwords don't match! Exiting."
exit
else
#if they match, make sure they're not empty
if [ -z "$mypassword1" ]
then
echo "Password cannot be empty... Exiting."
else
tar zcp $dirToBackup | openssl des3 -salt -pass pass:$mypassword1 | ssh ${sshuser}#${sshserver} "dd of=${targetDir}"
fi
fi
I want to encrypt and decrypt one file using one password.
How can I use OpenSSL to do that?
Security Warning: AES-256-CBC does not provide authenticated encryption and is vulnerable to padding oracle attacks. You should use something like age instead.
Encrypt:
openssl aes-256-cbc -a -salt -pbkdf2 -in secrets.txt -out secrets.txt.enc
Decrypt:
openssl aes-256-cbc -d -a -pbkdf2 -in secrets.txt.enc -out secrets.txt.new
More details on the various flags
Better Alternative: GPG
Though you have specifically asked about OpenSSL you might want to consider using GPG instead for the purpose of encryption based on this article OpenSSL vs GPG for encrypting off-site backups?
To use GPG to do the same you would use the following commands:
To Encrypt:
gpg --output encrypted.data --symmetric --cipher-algo AES256 un_encrypted.data
To Decrypt:
gpg --output un_encrypted.data --decrypt encrypted.data
Note: You will be prompted for a password when encrypting or decrypt. And use --no-symkey-cache flag for no cache.
RE: OpenSSL - Short Answer
You likely want to use gpg instead of openssl so see "Additional Notes" at the end of this answer. But to answer the question using openssl:
To Encrypt:
openssl enc -aes-256-cbc -in un_encrypted.data -out encrypted.data
To Decrypt:
openssl enc -d -aes-256-cbc -in encrypted.data -out un_encrypted.data
Note: You will be prompted for a password when encrypting or decrypt.
RE: OpenSSL - Long Answer
Your best source of information for openssl enc would probably be: https://www.openssl.org/docs/man1.1.1/man1/enc.html
Command line:
openssl enc takes the following form:
openssl enc -ciphername [-in filename] [-out filename] [-pass arg]
[-e] [-d] [-a/-base64] [-A] [-k password] [-kfile filename]
[-K key] [-iv IV] [-S salt] [-salt] [-nosalt] [-z] [-md] [-p] [-P]
[-bufsize number] [-nopad] [-debug] [-none] [-engine id]
Explanation of most useful parameters with regards to your question:
-e
Encrypt the input data: this is the default.
-d
Decrypt the input data.
-k <password>
Only use this if you want to pass the password as an argument.
Usually you can leave this out and you will be prompted for a
password. The password is used to derive the actual key which
is used to encrypt your data. Using this parameter is typically
not considered secure because your password appears in
plain-text on the command line and will likely be recorded in
bash history.
-kfile <filename>
Read the password from the first line of <filename> instead of
from the command line as above.
-a
base64 process the data. This means that if encryption is taking
place the data is base64 encoded after encryption. If decryption
is set then the input data is base64 decoded before being
decrypted.
You likely DON'T need to use this. This will likely increase the
file size for non-text data. Only use this if you need to send
data in the form of text format via email etc.
-salt
To use a salt (randomly generated) when encrypting. You always
want to use a salt while encrypting. This parameter is actually
redundant because a salt is used whether you use this or not
which is why it was not used in the "Short Answer" above!
-K key
The actual key to use: this must be represented as a string
comprised only of hex digits. If only the key is specified, the
IV must additionally be specified using the -iv option. When
both a key and a password are specified, the key given with the
-K option will be used and the IV generated from the password
will be taken. It probably does not make much sense to specify
both key and password.
-iv IV
The actual IV to use: this must be represented as a string
comprised only of hex digits. When only the key is specified
using the -K option, the IV must explicitly be defined. When a
password is being specified using one of the other options, the
IV is generated from this password.
-md digest
Use the specified digest to create the key from the passphrase.
The default algorithm as of this writing is sha-256. But this
has changed over time. It was md5 in the past. So you might want
to specify this parameter every time to alleviate problems when
moving your encrypted data from one system to another or when
updating openssl to a newer version.
Encrypt:
openssl enc -in infile.txt -out encrypted.dat -e -aes256 -k symmetrickey
Decrypt:
openssl enc -in encrypted.dat -out outfile.txt -d -aes256 -k symmetrickey
For details, see the openssl(1) docs.
DO NOT USE OPENSSL DEFAULT KEY DERIVATION.
Currently the accepted answer makes use of it and it's no longer recommended and secure.
It is very feasible for an attacker to simply brute force the key.
https://www.ietf.org/rfc/rfc2898.txt
PBKDF1 applies a hash function, which shall be MD2 [6], MD5 [19] or
SHA-1 [18], to derive keys. The length of the derived key is bounded
by the length of the hash function output, which is 16 octets for MD2
and MD5 and 20 octets for SHA-1. PBKDF1 is compatible with the key
derivation process in PKCS #5 v1.5. PBKDF1 is recommended only for compatibility with existing
applications since the keys it produces may not be large enough for
some applications.
PBKDF2 applies a pseudorandom function (see Appendix B.1 for an
example) to derive keys. The length of the derived key is essentially
unbounded. (However, the maximum effective search space for the derived key may be limited by the structure of the underlying
pseudorandom function. See Appendix B.1 for further discussion.)
PBKDF2 is recommended for new applications.
Do this:
openssl enc -aes-256-cbc -pbkdf2 -iter 20000 -in hello -out hello.enc -k meow
openssl enc -d -aes-256-cbc -pbkdf2 -iter 20000 -in hello.enc -out hello.out
Note: Iterations in decryption have to be the same as iterations in encryption.
Iterations have to be a minimum of 10000.
Here is a good answer on the number of iterations: https://security.stackexchange.com/a/3993
Also... we've got enough people here recommending GPG. Read the damn question.
As mentioned in the other answers, previous versions of openssl used a weak key derivation function to derive an AES encryption key from the password. However, openssl v1.1.1 supports a stronger key derivation function, where the key is derived from the password using pbkdf2 with a randomly generated salt, and multiple iterations of sha256 hashing (10,000 by default).
To encrypt a file:
openssl aes-256-cbc -e -salt -pbkdf2 -iter 10000 -in plaintextfilename -out encryptedfilename
To decrypt a file:
openssl aes-256-cbc -d -salt -pbkdf2 -iter 10000 -in encryptedfilename -out plaintextfilename
Note: An equivalent/compatible implementation in javascript (using the web crypto api) can be found at https://github.com/meixler/web-browser-based-file-encryption-decryption.
Update using a random generated public key.
Encypt:
openssl enc -aes-256-cbc -a -salt -in {raw data} -out {encrypted data} -pass file:{random key}
Decrypt:
openssl enc -d -aes-256-cbc -in {ciphered data} -out {raw data}
To Encrypt:
$ openssl bf < arquivo.txt > arquivo.txt.bf
To Decrypt:
$ openssl bf -d < arquivo.txt.bf > arquivo.txt
bf === Blowfish in CBC mode
There is an open source program that I find online it uses openssl to encrypt and decrypt files. It does this with a single password. The great thing about this open source script is that it deletes the original unencrypted file by shredding the file. But the dangerous thing about is once the original unencrypted file is gone you have to make sure you remember your password otherwise they be no other way to decrypt your file.
Here the link it is on github
https://github.com/EgbieAnderson1/linux_file_encryptor/blob/master/file_encrypt.py
Note that the OpenSSL CLI uses a weak non-standard algorithm to convert the passphrase to a key, and installing GPG results in various files added to your home directory and a gpg-agent background process running. If you want maximum portability and control with existing tools, you can use PHP or Python to access the lower-level APIs and directly pass in a full AES Key and IV.
Example PHP invocation via Bash:
IV='c2FtcGxlLWFlcy1pdjEyMw=='
KEY='Twsn8eh2w2HbVCF5zKArlY+Mv5ZwVyaGlk5QkeoSlmc='
INPUT=123456789023456
ENCRYPTED=$(php -r "print(openssl_encrypt('$INPUT','aes-256-ctr',base64_decode('$KEY'),OPENSSL_ZERO_PADDING,base64_decode('$IV')));")
echo '$ENCRYPTED='$ENCRYPTED
DECRYPTED=$(php -r "print(openssl_decrypt('$ENCRYPTED','aes-256-ctr',base64_decode('$KEY'),OPENSSL_ZERO_PADDING,base64_decode('$IV')));")
echo '$DECRYPTED='$DECRYPTED
This outputs:
$ENCRYPTED=nzRi252dayEsGXZOTPXW
$DECRYPTED=123456789023456
You could also use PHP's openssl_pbkdf2 function to convert a passphrase to a key securely.