Increase the maximum line length

Oct 13, 2025 by talynt.org 95 views

Introduction

HashCat is a popular password cracking tool that supports a wide range of hash types, including bcrypt, Blowfish (Unix), and many others. In this article, we will explore the process of using HashCat to decrypt a bcrypt $2*$ hash, which is a type of Blowfish (Unix) hash. We will also discuss the line-length exception that can occur when using HashCat with this type of hash.

**Understanding bcrypt $2*$ Hashes**

Bcrypt $2*$ hashes are a type of Blowfish (Unix) hash that uses a specific algorithm to encrypt passwords. The $2*$ prefix indicates that the hash is a bcrypt hash, and the following characters represent the salt and the number of iterations used to encrypt the password. The bcrypt algorithm is designed to be slow and computationally expensive, making it more resistant to brute-force attacks.

**Using HashCat with bcrypt $2*$ Hashes**

To use HashCat with a bcrypt $2*$ hash, you will need to specify the hash type and the hash itself in the HashCat command. The command will look something like this:

hashcat -m 3200 -a 0 -o output.txt example_hash.txt

In this command, -m 3200 specifies the hash type (bcrypt $2*$ ), -a 0 specifies the attack mode (dictionary attack), and -o output.txt specifies the output file. The example_hash.txt file contains the hash to be cracked.

The Line-length Exception

When using HashCat with a bcrypt $2*$ hash, you may encounter a line-length exception. This exception occurs when the hash is too long to fit on a single line, causing HashCat to fail. To resolve this issue, you can use the -L option to specify the maximum line length. For example:

hashcat -m 3200 -a 0 -L 100 -o output.txt example_hash.txt

In this command, -L 100 specifies the maximum line length (100 characters).

Resolving the Line-length Exception

If you encounter a line-length exception, you can try the following:

Increase the maximum line length: You can increase the maximum line length by specifying a higher value for the -L option. For example:

hashcat -m 3200 -a 0 -L 200 -o output.txt example_hash.txt

Use a different hash type: If the line-length exception persists, you can try using a different hash type. For example, you can use the -m 3201 option to specify the bcrypt $2*$ hash type without the line-length exception.
Use a different attack mode: You can try using a different attack mode, such as the -a 1 option to specify a brute-force attack.

Example Use Case

Let's say you have a bcrypt $2*$ hash that you want to crack using HashCat. The hash is:

$2a $05$ LhayLxezLhK1LhWvKxCyLOj0j1u....

To crack this hash, you can use the following command:

hashcat -m 3200 -a 0 -o output.txt example_hash.txt

Conclusion

In conclusion, using HashCat with bcrypt $2*$ hashes can be a bit tricky due to the line-length exception. However, by specifying the maximum line length and using different hash types and attack modes, you can resolve this issue and crack the hash successfully. Remember to always use the correct hash type and attack mode to ensure the best results.

Troubleshooting

If you encounter any issues while using HashCat with bcrypt $2*$ hashes, you can try the following:

Check the hash type: Make sure you are using the correct hash type (-m 3200) for bcrypt $2*$ hashes.
Check the attack mode: Make sure you are using the correct attack mode (-a 0) for dictionary attacks.
Check the maximum line length: Make sure you are specifying the correct maximum line length (-L) to avoid the line-length exception.
Check the output file: Make sure you are specifying the correct output file (-o) to store the cracked hash.

Additional Resources

For more information on using HashCat with bcrypt $2*$ hashes, you can refer to the following resources:

HashCat documentation: https://hashcat.net/docs/
Bcrypt documentation: https://en.wikipedia.org/wiki/Bcrypt
Blowfish (Unix) documentation: https://en.wikipedia.org/wiki/Blowfish_(cipher)
HashCat bcrypt $2*$ , Blowfish (Unix) Line-length exception: Q&A ===========================================================

**Q: What is a bcrypt $2*$ hash?**

A: A bcrypt $2*$ hash is a type of Blowfish (Unix) hash that uses a specific algorithm to encrypt passwords. The $2*$ prefix indicates that the hash is a bcrypt hash, and the following characters represent the salt and the number of iterations used to encrypt the password.

Q: What is the line-length exception in HashCat?

A: The line-length exception in HashCat occurs when the hash is too long to fit on a single line, causing HashCat to fail. This can happen when using bcrypt $2*$ hashes, which can be quite long.

Q: How do I resolve the line-length exception in HashCat?

A: To resolve the line-length exception, you can try the following:

Increase the maximum line length: You can increase the maximum line length by specifying a higher value for the -L option. For example:

hashcat -m 3200 -a 0 -L 200 -o output.txt example_hash.txt

Use a different hash type: If the line-length exception persists, you can try using a different hash type. For example, you can use the -m 3201 option to specify the bcrypt $2*$ hash type without the line-length exception.
Use a different attack mode: You can try using a different attack mode, such as the -a 1 option to specify a brute-force attack.

**Q: What is the difference between bcrypt $2$ and bcrypt $2a$ ?**

A: The main difference between bcrypt $2*$ and bcrypt $2a*$ is the number of iterations used to encrypt the password. Bcrypt $2*$ uses 2^10 iterations, while bcrypt $2a*$ uses 2^12 iterations.

**Q: Can I use HashCat to crack bcrypt $2a*$ hashes?**

A: Yes, you can use HashCat to crack bcrypt $2a*$ hashes. However, you will need to specify the correct hash type (-m 3201) and the correct number of iterations (2^12).

Q: How do I specify the correct hash type in HashCat?

A: To specify the correct hash type in HashCat, you can use the -m option followed by the hash type number. For example:

hashcat -m 3200 -a 0 -o output.txt example_hash.txt

In this command, -m 3200 specifies the bcrypt $2*$ hash type.

**Q: Can I use HashCat to crack hashes that are not bcrypt $2*$ ?**

A: Yes, you can use HashCat to crack hashes that are not bcrypt $2*$ . HashCat supports a wide range of hash types, including MD5, SHA-1, and many others.

Q: How do I specify the correct attack mode in HashCat?

A: To specify the correct attack mode in HashCat, you can use the -a option followed by the attack mode number. For example:

hashcat -m 3200 -a 0 -o output.txt example_hash.txt

In this command, -a 0 specifies the dictionary attack mode.

Q: Can I use HashCat to crack hashes that are stored in a database?

A: Yes, you can use HashCat to crack hashes that are stored in a database. HashCat supports a wide range of database formats, including MySQL and PostgreSQL.

Q: How do I specify the correct database format in HashCat?

A: To specify the correct database format in HashCat, you can use the -d option followed by the database format name. For example:

hashcat -m 3200 -a 0 -d mysql -o output.txt example_hash.txt

In this command, -d mysql specifies the MySQL database format.

Q: Can I use HashCat to crack hashes that are stored in a file?

A: Yes, you can use HashCat to crack hashes that are stored in a file. HashCat supports a wide range of file formats, including text files and binary files.

Q: How do I specify the correct file format in HashCat?

A: To specify the correct file format in HashCat, you can use the -f option followed by the file format name. For example:

hashcat -m 3200 -a 0 -f text -o output.txt example_hash.txt

In this command, -f text specifies the text file format.

Conclusion

In conclusion, HashCat is a powerful tool for cracking hashes, including bcrypt $2*$ hashes. By understanding the line-length exception and how to resolve it, you can use HashCat to crack hashes successfully. Remember to always specify the correct hash type, attack mode, and database or file format to ensure the best results.