Posted on Leave a comment

Linux hacking guide for beginners

Hello, aspiring ethical hackers. In this blogpost, you will learn about Linux hacking. It comes under gaining access, third of the 5 phases of ethical hacking.

What is Linux hacking?

Although Linux hacking can be generalized as any type of hacking attempt made on Linux systems, gaining initial access to the Linux system can be termed as Linux Hacking.

Why is it important?

Linux hacking is one of the most important topics in ethical hacking. Why? According to the Statcounter global stats, as of March 2024 operating system market share, the topmost operating systems being used around the world are Linux or its variants. The same report also states that usage of Linux as desktop increased to 4.05% this year. Also note that majority of the servers around the world are Linux servers. So, learning Linux hacking can provide lot of knowledge. But what are the various methods used for hacking Linux systems.

Linux hacking techniques

There are multiple ways by which hackers can gain initial access on Linux systems. They are,

  1. Vulnerabilities in the operating system or kernel
  2. Application vulnerabilities.
  3. Payloads & malicious software.
  4. Password attacks.
  5. Misconfigured services.
  6. Social- engineering

1. Vulnerabilities in the operating system or kernel:

An operating system or kernel is the core of any Linux system. Organizations around the world use various versions of Linux operating system for different purposes. So, any vulnerability exposed in the operating system can be exploited by hackers to gain initial access.

For example, in 2014, a vulnerability named Heartbleed was detected in the OpenSSL package that comes inbuilt with Linux kernel. It was used to exploit HTTPS enabled websites of Yahoo, Google, Dropbox, Facebook and other thousands of websites.

2. Application vulnerabilities:

A lot of applications or programs are installed on Linux for performing various functions. Any vulnerabilities in these installed programs can be exploited successfully to hack the Linux system. For example, hackers exploited Apache ActiveMQ software to deploy Kinsing malware on the infected systems in November 2023, Apache ActiveMQ is used as a communication bridge between multiple components that can be hosted on separate servers.

3. Malicious payloads:

Hackers just don’t use vulnerabilities to gain access. They also use malicious payloads like malware and virus to hack Linux systems. Since 2023, malware especially ransomware designed for Linux systems in or the rise. This malware is usually delivered by exploiting vulnerabilities, phishing attack or drive-by downloads. Examples of some payload generators are msfvenom, Veil, MSFPC, Cypher etc.

4. Password attacks:

As already mentioned, most of the servers in the world are built on Linux as it is open source. These include services like FTP, HTTP, SSH etc. If credentials of any of these services are cracked by hackers, it will provide a way to gain access to the underlying Linux server. Learn more about password cracking.

5. Misconfigured services:

Sometimes, services being used in the target Linux systems can be misconfigured either by mistake or by ignorance. Hackers can exploit these misconfigurations to hack the Linux system. For example, in March 2023, an advanced malware campaign exploited misconfigurations in Apache Hadoop, YARN, Docker, Confluence and Redis on Linux instances.

7. Social-engineering:

No matter how strong the firewall on the network is or how secure the Linux devices are in a network, if the employees of the organization are not well trained, they can eventually give hackers access into the network or Linux devices. Social-engineering is often very underrated as a factor that allows hackers to hack Linux systems. Learn more about social engineering.

Posted on Leave a comment

Windows hacking guide for beginners

Hello, aspiring ethical hackers. This article is a beginners guide for Windows hacking. It comes under gaining access, third of the 5 phases of ethical hacking.

What is Windows hacking?

Although Windows hacking can be generalized to any hacking performed on the Windows operating system, gaining initial access to the Windows systems is known as Windows hacking.

Why is it important?

According to StatCounter Global Stats, over 72.52% of people worldwide use Windows as their Desktop. That is the reason why Windows hacking is one of the most important topics of ethical hacking.

Windows hacking techniques

There are multiple ways by which hackers can gain initial access on Windows systems. They are,

  1. Vulnerabilities in the operating system or kernel
  2. Application vulnerabilities.
  3. Payloads & malicious software.
  4. Password attacks.
  5. Misconfigured services.
  6. Social- engineering

1. Vulnerabilities in the operating system or kernel:

An operating system or kernel is the core of any Windows system. Enterprises around the world use Windows operating system for various purposes. As already mentioned, according to StatCounter Global Stats, over 72.52% of people worldwide use Windows as their Desktop. So, any vulnerability exposed in the operating system can be exploited by hackers to gain initial access.

For example, in 2008, ms08-067 vulnerability was exploited by Conficker worm to infect millions of devices around the world. Similarly, another vulnerability in Windows software, Eternal Blue (ms17-010) was exploited by NSA for intelligence gathering and counter terrorism missions. When this vulnerability got leaked, it was exploited by the WannaCry ransomware attack that infected 2,30,000 Windows PCs across 150 countries.

2. Application vulnerabilities:

A lot of applications or programs are installed in Windows operating system to perform various functions. Any vulnerabilities in these installed programs can be exploited successfully to hack the Windows system. For example, macros feature in Microsoft office has been exploited for a long time by hacker groups around the world to gain initial access until this was banned officially by Microsoft. Macros is a feature in Microsoft office to automate procedures.

In 2022, Chinese hacker group Cicada, exploited VLC Media Player, a popular and open source multimedia player to hack Windows systems and installed malware for espionage purpose. They did this by embedding a malicious file alongside the VLC Media Player’s export functions.

3. Malicious payloads:

Hackers just don’t use vulnerabilities to gain access. They also use malicious payloads like malware and virus to hack Windows systems. These payloads can be spread by using dive-by downloads or phishing. For example, Zeus trojan that specializes stealing banking information is spread through same techniques mentioned above. Examples of some payload generators are msfvenom, Veil, MSFPC, Cypher etc.

4. Password attacks:

Some Enterprise Windows systems are enabled with remote access so that employees can connect to them remotely for the purpose of their work. The protocols enabling remote access like SSH, FTP, Telnet and RDP etc. Cracking the credentials of these services give hackers a way to gain access to the servers and subsequently to the Windows system. Learn more about password cracking.

As recently as November 2023, a Russian Hacker group (Midnight Blizzard) used password spraying attack, a type of password attack to compromise some corporate accounts of Microsoft users.

5. Misconfigured services:

Sometimes, services being used in the target Windows network can be misconfigured either by mistake or on purpose. Hackers can exploit these misconfigurations to hack the Windows system. In October 2022, Microsoft company exposed one endpoint to public internet without authentication. This led to data leak of 65,000 customers in 111 countries. The total size of the stolen data was 2.4 terabytes.

7. The human factor:

No matter how strong the firewall on the network is or how secure the Windows devices are in a network, if the employees of the organization are not well trained, they can eventually give hackers access into the network or Windows devices. Social-engineering is often very underrated as a factor that allows hackers to hack Windows systems. Learn more about social engineering.

Posted on Leave a comment

Covering tracks in ethical hacking

Hello, aspiring ethical hackers. In this blogpost, you will learn about covering tracks which is the last of the 5 phases of ethical hacking.

What is Covering tracks?

Covering tracks or clearing tracks is the phase of ethical hacking in which a hacker tries to erase all the evidence on the target system that can lead back to the hacker. For covering tracks, hackers perform various actions. They are,

1. Uninstalling executables and scripts:

Hackers install many scripts and executables on the target system as part of their hacking attack. These scripts may help hackers cracking passwords, privilege escalation, maintaining access etc. Detection of these scripts and executables on the target system can lead the investigators to the hacker. So, hackers uninstall or delete any scripts or executables they have used in carrying the hacking attack.

2. Clearing logs:

Every operating system has its own logs that record different operational activities being performed on the operating system. They also record any actions performed by hackers. When an incident investigator observes these logs, he can easily deduce what the hacker did on the target system. To prevent this, hackers clear these logs to hide whatever they did on the target system.

Fig: Event Viewer in Windows where all logs can be viewed
Fig: In Linux all logs are stored in the “/var/log/” directory

3. Timestamping files:

Every file on the operating system has a time stamp which reveals information about the file like the date of its creation, last modified time etc. Hackers change this timestamp of the files appropriately to prevent detection of the modifications they made to files inadvertently while hacking.

Fig: Timestamp of a file in Windows
Fig: Timestamp of a file in Linux

4. Modifying registry values:

The Windows Registry in the Windows operating system is a hierarchical database that contains information, settings, options, and other values for programs and hardware installed on the Windows operating system. Changes made to some program can also be detected by viewing this registry. So, hackers also modify these registry values to hide their malicious activity.

Fig: Windows Registry
Posted on Leave a comment

Maintaining access in ethical hacking

Hello, aspiring ethical hackers. In this blogpost, you will learn about maintaining access in ethical hacking. Maintaining access is the fourth phase in the total 5 phases of ethical hacking. In this phase, hackers try to hold on to the initial access or foothold they have gained on the network.

This is done using various methods. They are,

1. Elevating privileges:

Most of the time when hackers gain initial access on the target system or network, it is a lower privileged one. So, as soon as hackers gain access, they try to elevate their privileges on the target system to be able to perform important actions on the target network or system. Learn more about privilege escalation.

2. Backdooring:

In this method of maintaining access, hackers try to install a backdoor on the target system or network. They do this by either modifying the legitimate components or by installing specific backdoors like C&C servers, genuine remote administration software etc.

3. Rootkits:

Sometimes, hackers install rootkits on the target system or network. A rootkit is a type of malware that masks its existence from the system software including Antivirus. Normally a rootkit provides higher level of access or sometimes even kernel level access to hackers.

4. Persistence scripts:

Hackers also use widely available persistence scripts to maintain access on the target system of the network.

5. Tunneling:

Maintaining access is not always about installing a backdoor or rootkit etc on the target system. Sometimes, it involves tunneling. Tunneling is a process in which data is usually shared between two different networks privately without being detected.

Posted on

5 phases of ethical hacking for beginners

Hello, aspiring ethical hackers. In this blogpost, you will learn what is ethical hacking and the 5 phases of ethical hacking.

What is Ethical Hacking?

Ethical hacking is hacking that is performed while following the ethics and rules. It is a procedure of detecting vulnerabilities and weaknesses in the target organization’s network and exploiting them with the written permission of an individual or organization. It is performed to find out and fix the vulnerabilities in the network that can be exploited by bad hackers aka Black Hat hackers.

What are the 5 phases of ethical hacking?

Ethical hacking consists of 5 phases. They are,

1. Foot printing:

Also known as information gathering or reconnaissance, in this phase ethical hackers try to collect as much information as possible about the target organization or individual that may be helpful to them in the next phases of ethical hacking. Learn more about Footprinting.

2. Scanning & enumeration:

In this phase, the target organization’s network is probed to find any path of entry that can provide a way for ethical hackers into the network. It includes scanning for live systems in the network range, scanning for open ports on the LIVE systems and services running on them and scanning for any vulnerabilities in those services.

Then these services are enumerated to find any user accounts or other Information about the target networks. Learn more about scanning & enumeration.

3. Gaining access:

In this phase ethical hacking, ethical hackers exploit one of the vulnerability or weakness found in the second phase and gain a shell on the target system or network. Learn more about gaining access.

4. Maintaining access:

In this phase, ethical hackers after gaining initial access on the target system or network, try to maintain this access for future and continuous use. Learn more about various techniques used for maintaining access.

5. Covering tracks:

In this phase, ethical hackers try to hide or erase all their operations performed on the target system or network until now. This is to remove any evidence of their malicious activity. In Black Hat Hacking, they do this to prevent tracing of the hack back to them. This phase is also known as clearing tracks. Learn more about covering tracks.