> For the complete documentation index, see [llms.txt](https://cas-cyber.gitbook.io/cas-cybersecurity/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cas-cyber.gitbook.io/cas-cybersecurity/master.md).

# Reconnaissance

### Passive/Active Information Gathering

#### Active Reconnaissance

In this process, you will directly interact with the computer system to gain information. This information can be relevant and accurate. But there is a risk of getting detected if you are planning active reconnaissance without permission. If you are detected, then system admin can take severe action against you and trail your subsequent activities.

#### Passive Reconnaissance

In this process, you will not be directly connected to a computer system. This process is used to gather essential information without ever interacting with the target systems

A good start for this is the OSINT Framework, which provides a powerfull wiki: [https://www.osintframework.com ](https://www.osintframework.com/)

<div align="left"><img src="/files/-Mg6fSKej6tRzXlzBlrX" alt="The OSINT Framework wiki"></div>

The list is huge and I'll just cover a few of them, which I also used during the CAS.

### Find Email Adresses

Hunter: <https://hunter.io/search/>

![huntio.io search field (you need to register if you want to see results)](/files/-Mg7LZmHAZwt6EB9dBmj)

Results looks like this:

![Gathered e-mail addresses from domain csnc.ch](/files/-Mg7Nosc3vVPgDcBC1N1)

Another cool tool is called theHarvester: <http://www.edge-security.com/theharvester.php>&#x20;

> theHarvester -d csnc.ch -l 1000 -b bing

<div align="left"><img src="/files/-Mg7SjkjiBT2e9EP7ARg" alt="Output from theHarvester"></div>

Another useful tool to check if a gathered e-mail adress is valid or not can be: <https://www.mailboxvalidator.com/demo>

![sample input for mail adress](/files/-Mg7VDJm0_-hNKZRDprV)

Result:

![sample above belongs to a Catch-all domain](/files/-Mg7WNHQ5CNPmh_udbcl)

### Check e-mail adress for breached data:

{% embed url="<https://haveibeenpwned.com/>" %}

{% embed url="<https://dehashed.com/>" %}

### Subdomain and Certificate Search

{% embed url="<https://pentest-tools.com/information-gathering/find-subdomains-of-domain#>" %}

{% embed url="<https://crt.sh/>?" %}

{% embed url="<https://search.censys.io/>" %}

{% embed url="<https://spyse.com/>" %}

### Vulnerability search

{% embed url="<https://github.com/1N3/Sn1per>" %}

### DNS Enumeration

{% embed url="<https://dnsdumpster.com/>" %}

### Reconnaisance Tools

{% embed url="<https://www.spiderfoot.net/>" %}

This is just a short overview! For more ressources please check out the OSINT Framework Website :)


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