> For the complete documentation index, see [llms.txt](https://ret2basic.gitbook.io/ctfnote/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ret2basic.gitbook.io/ctfnote/red-teaming/exploitation/password-spray.md).

# Password Spray

## What is Password Spray?

Rather than the usual dictionary brute force methods involving a dictionary of hundreds if not millions of password entries, the idea of **password spray** is to reverse the process: introduce a list of **as many users as possible**, while trying just **a single password** attempt against tens or hundreds of user accounts.

## Username Enumeration

Here is a username list example:

<https://github.com/insidetrust/statistically-likely-usernames>

We can enumerate usernames using SMTP `VRFY` method:

```shell
head -n 50 john.txt > users.txt
smtp-user-enum -M VRFY -U users.txt -t $IP
```

This is same as the Metasploit module `auxiliary/scanner/smtp/smtp_enum` .

## Password Selection

Now that we have validated some users, we should determine **one** (recommended) or two (maximum) commonly-used passwords we can use for our attack.

Regarding commonly used passwords, real-world experience has shown that one of the most commonly used passwords are usually found to be the **current season**, along with the current year, e.g., **Spring2022**.

Another very common password is **"CompanyName"** along with a numerical value, e.g., **FooCorp01**, **FooCorp02**, etc.

## SSH Password Spray

Spray a single server:

```shell
hydra -L users.txt -p <password> ssh://$IP -t 4
```

Spray multiple servers:

```shell
hydra -l <username> -p <password> -M ssh_servers.txt ssh -t 4
```

{% hint style="danger" %}
When bruteforcing SSH, always use **4 threads**. This is because >= 4 threads may get caught by defense mechanism.
{% endhint %}


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