linux login showing bash-4.1 command line

Linux Shell Login Showing bash-4.1 command line, How do i change bash-4.1# to user@hostname ?

How do i change bash-4.1# to user@hostname when login on linux PC Desktop Server

If you are facing above issue during login on Linux PC Desktop Servers so this may help to resolve the issue. 
What is Bash ? 

Bash is a Unix shell and command language written by Brian Fox for the GNU Project as a free software replacement for the Bourne shell. First released in 1989, it has been used as the default login shell for most Linux distributions. A version is also available for Windows 10 via the Windows Subsystem for Linux.

Problem occurs with login shells

If the problem occurs with login shells as well as non-login shells, the problem is probably the same as above. If it occurs only with login shells, you either don't have one of the files mentioned for login shells under the INVOCATION quote above, or they don't source your ~/.bashrc, which is normal on most linux distros. If none of those files exists, create ~/.bash_profile with this in it:
if [ -f ~/.bashrc ]; then
  . ~/.bashrc
This allows you, for the most part, to keep your configuration in one file (~/.bashrc).
If no matter what you do you cannot get a prompt back, you can create one and put it into ~/.bashrc this way:
if [ "$PS1 ]; then
    PS1= .... # see below
This is because $PS1 is set and has a default value for interactive shells, and you don't want to set it otherwise since other things may use this value to determine whether this is an interactive environment.
The bash man page contains a section PROMPTING which describes how to set a prompt with dynamic features such as your user name and current working directory, which would be, e.g.,:

To change bash-4.1# to user@hostname

Just go to /etc/skel 

run command $ls -a  it will show 

.bash_logout  .bash_profile  .bashrc  .kshrc 

Now cp bash_profile  .bashrc /home/username

try to log out and login again you will notice normal bash prompt. 


What is /etc/skel files under Linux systems ?

The /etc/skel directory contains some of the files and directories that are automatically copied over to a new linux user's when it is created using useradd command. it ensures that all the users gets same intial settings and environment.

Skel is basically derived from the "skeleton" because it contains basic structure of linux user home directory. under the path of /etc/skel directory contains files and directories. 

What is the use of /etc/skel directory in linux ?

If your linux system required to distribute default configuration files  you can add that to the directory, when you add any new user and you have chosen to create a home directory while setting up the new user, the files that are contained within /etc/skel directory are copied into the home directory of the new user.

What is a .bashrc file in linux ?

The .bashrc  file normally we can find under users's home area /home/username .bashrc is a script file that's executed when any user logs in. The file itself contains a series of configurations for the terminal session. This includes setting up or enabling coloring, completion, shell history, command aliases, and many more. this is a kind of hidden file and imple ls command won't show the file in your home area if you want to see your .bashrc file use the command ls -a command to view and make necessary changes if required.

type of cyber attack is being commonly performed by hacker

Basic fundamental of cyber security| beginner to expert guide| Type of Cyber Security & Tools 2021  

Cyber security is practices of protecting computer network, software program, computing resources and IT related equipment from unauthorized digital access and hacking attempt. 

साइबर सुरक्षा:- अनधिकृत डिजिटल एक्सेस और हैकर हमले से कंप्यूटर नेटवर्कसॉफ्टवेयर प्रोग्रामकंप्यूटर सिस्टम और आईटी से संबंधित उपकरणों की सुरक्षा करने का तरीका है।

Type of cyber attacks | साइबर हमले का प्रकार |  

1. Malware Attack :- Malware is a very common cybers attack, Trojan, Adware, Spyware, Suspicious Attachment, Virus Mails, Keylogger, Worms, E-mail attachment are the group of malicious software program use to execute "malware attack".  

मालवेयर अटैक- (ट्रोजनएडवेयरस्पाईवेयरसस्पेंस अटैचमेंटवायरस मेलकीलॉगरवर्म्स आदि मुख्य प्रकार है| 

2. Advance persistent Threat (APT) :- PSU or govt organization usually face Advance persistent Threat (APT) attack, through APT hacker  can get access for prolong period of time. In order to continually gain      access of confidential data. 

3. Denial of Service (DOS) :- DOS attack flood services request using multiple        servers. which stops legitimist service request. Advance version of DOS  is,  Distributed Denial of services (DDOS), where hacker send multiple requests to the resource,  flood the bandwidth result Denial of Service attack to harm the organization.   

4. SQL injection:-  Hacker can manipulate query in database, hacker can view, edit, delete any data in any vulnerable database server.

5. Man-in-the-middle Attack :-  Man-in-the-middle Attack is also      through malware, known as the network attack or eavesdropping attack, where hacker can hijacks session between the client and the server, and capture data during transections due to unsecure public network.  

6. Type of Password attack: 

  • Dictionary attack
  • Brute force (trail and error method), It takes long time using combination and permutation.
  • keylogger attack can capture users typed data. 
  • Shoulder surfing, by looking over the user's shoulder.
  • Rainbow table (Attacker use hash table to find the password of user capture hash value). 

7. Social Engineering Attack :- Convince someone to get personal information.

8. Phishing attack:- Practices to send fake mail and get access non targeted attack.

9. Spear Phishing Attack:- Targeted attack individual or group by identify the flaws and gullibility of victims.

10. Whaling Phishing Attack:- when target to wealthy and powerful people such as CEO, CFO are targeted. 

Tools and idea to Prevent Cyber Attack and Security method :-

1. Firewall - Software, Hardware.

2. Honeypot (honeypot is a computer security mechanism set to detect,  deflect, or, in some manner, counteract attempts from unauthorized access.)

3. Strong Password policy

4. Anti Virus

5. Avoid E-mail from unknown Sources.  

6. DMZ : A demilitarized zone, is a subnetwork that sits between the public internet and private networks adds an extra layer of security to protect the sensitive data stored on internal networks DMZ approach makes it more difficult for a hacker to gain direct access to an organization’s data.

Some of the popular Cyber Attacks:

1. WanaCry ransomware attack in 2017 due to windows Vulnerability found in (server message block) SMB  within a day more than 2,30,000 computers were infected across 150 countries. it encrypted the data of users demanded $300 to $600 to decrypt.

2. In February 2019, Dunkin Donuts users were targeted and users 

credentials were stolen. 

Why Cyber Attack are being done ?  साइबर अटैक क्यों किया जा रहा है ?

The of purpose of cyber attack is to temper data for monitory gain or harm any user/organization.


1. Disrupting business Continuity.

2. Manipulating data.

3. Create fear and chaos by disrupting critical infrastructure.

4. Financial loss of the target.

5. Achieve military objectives.

6. Demand ransom.

7. Damage reputation of the target.

8. Propagating religious or political beliefs.

Terminologies of Cyber Security:

1. Network:- Network is a group of devices connected to each other through wired or  wireless. 

2. Server/Client :- Server is a computer hardware or software that provides functionality for other programs or devices, called "clients". This architecture is called the client–server model.

3. Internet :- Internet is globally connected set of network.

4. Network Protocol :- Network Protocol is the defined set of rules that determine the data connectivity and transmission between devices through internet.  

5. TCP/UDP : If TCP/UDP would not have been there our network would have collapse. 

6. IP address : IP address helps to identify any device or website on internet, IP address is a 32 bit numerical address like ( assigned to each equipment on network, without IP any device can not connect to the internet.

7. Media Access Control (MAC):- Mac is also called Physical Address of any network equipment (Physical Address: ‎E0-69-95-DE-07-1D it's a unique identification number that assigned to each hardware in the network. known as physical address and it's can't be changed. 

Some of the most important cyber security related terminology.

What is cybersecurity ?

Cybersecurity refers to the protection of hardware, software, and data from attackers/hackers. The primary purpose of cyber security is to protect against cyberattacks like accessing, changing, or destroying sensitive information.

Elements of cybersecurity. 

The Major elements of cybersecurity are, Information security, Network security, Operational security, Application security, End-user awareness, Business continuity planning. 

Advantages of cyber security awareness

Awareness of cyber security helps you to  protects your business, organization against ransomwaremalwaresocial engineering, and phishing. It helps to  protects end-users. It gives good protection for both data as well as networks. Increase recovery time after a breach. Cybersecurity prevents unauthorized users.


Cryptography is a technique used to protect information from third parties called adversaries. Cryptography allows only sender and recipient of a message to read details about it.

Differentiate between IDS and IPS.

Intrusion Detection System (IDS) detects intrusions, The administrator has to be careful while preventing the intrusion. In the Intrusion Prevention System, the system finds the intrusion and prevent it from hackers.

What is CIA ?

Confidentiality, Integrity, and Availability (CIA) is a popular model which is designed to develop a security policy, CIA model three concepts:

  • Confidentiality: Ensure the sensitive data is accessed only by an authorized user. 
  • Integrity: Integrity means the information is in the right format.
  • Availability: Ensure the data and resources are available for users who need them.

Firewall in cyber security.

Firewall is a security system designed for the network. A firewall is set on the boundaries of any system or network which monitors and controls network traffic. Firewalls are mostly used to protect the system or network from malware, worms, and viruses. Firewalls can also prevent content filtering and remote access.

Type of Firewall:

  • Packet-filtering firewalls.
  • Circuit-level gateways.
  • Stateful inspection firewalls.
  • Application-level gateways (proxy firewalls)
  • Next-gen firewalls.
  • Software firewalls.
  • Hardware firewalls.
  • Cloud firewalls.

What is Traceroute ?

Traceroute is a tool, that shows the network packet path. It lists all the points that the network packet passes through on LAN/WAN. Traceroute is used mostly when the packet does not reach on the destination. Traceroute is used to check where the connection breaks or stops or to identify the failure.

(9) Differentiate between HIDS and NIDS ? 

  • HIDS :- Host-based intrusion detection system, use to monitoring and analyze the  computing system as well as the network packets on network interfaces, 

  • NIDS, Network intrusion detection system,  works in real-time, which means it tracks live data and flags issues as they happen. It detects malicious traffic on a network, in order to analyze network traffic, including all unicast traffic.

It monitors suspicious system activities and traffic of a specific device, It monitors the traffic of all device on the network.

What is  SSL ?

SSL stands for Secure Sockets Layer. It is a technology creating encrypted connections between a web server and a web browser. It is used to protect the information in online transactions and digital payments to maintain data privacy.

 Data leakage 

Data leakage is an unauthorized transfer of data to the outside world. Data leakage occurs via email, optical media, laptops, and USB keys.

What is Brute force attack, How can we prevent it ?

It is a trial-and-error method to find out the right password or PIN. Hackers repetitively try all the combinations of credentials. In many cases, brute force attacks are automated where the software automatically works to login with credentials. There are ways to prevent Brute Force attacks. using Setting password length. Increase password complexity. Set limit on login failures.  

Port scanning service

It is the technique for identifying open ports and service available on a specific host. Hackers use port scanning technique to find information for malicious purposes. 

Name the different layers of the OSI model.

Seven different layers of OSI models are as follows:

  • Physical Layer
  • Data Link Layer
  • Network Layer
  • Transport Layer
  • Session Layer
  • Presentation Layer
  • Application Layer

What is a VPN and it's usage ?

VPN stands for Virtual Private Network. It is a network connection method for creating an encrypted and safe connection. This method protects data from interference, snooping, censorship.

Black Hat hackers.

Black hat hackers are people who have a good knowledge of breaching network security. These hackers can generate malware for personal financial gain or other malicious reasons. They break into a secure network to modify, steal, or destroy data so that the network can not be used by authorized network users.

White hat hackers.

White hat hackers or security specialist are specialized in penetration testing. They protect the information system of an organization.

 Grey hat hackers.

Grey hat hackers are computer hacker who sometimes violate ethical standards, but they do not have malicious intent.

 How can we reset a password-protected BIOS configuration ?

There are various ways to reset BIOS password. Some of them are as follows:

  • Remove CMOS battery.
  • By utilizing the software.
  • By utilizing a motherboard jumper.
  • By utilizing MS-DOS.

 What is MITM attack ?

A MITM or Man-in-the-Middle is a type of attack where an attacker intercepts communication between two persons. The main intention of MITM is to access confidential information.

ARP and its working process.

It is a protocol used for finding MAC address associated with IPv4 address. This protocol work as an interface between the OSI network and OSI link layer.

About botnet.

It's a number of internet-connected devices like servers, mobile devices, IoT devices, and PCs that are infected and controlled by malware.

Main difference between SSL and TLS.

The main difference between these two is that SSL verifies the identity of the sender. SSL helps you to track the person you are communicating to. TLS offers a secure channel between two clients.

Abbreviation of CSRF ?

CSRF stands for Cross-Site Request Forgery. 

What is 2FA, how can we implement it for a public website ?

TFA stands for Two Factor Authentication. It is a security process to identify the person who is accessing an online account. The user is granted access only after presenting evidence to the authentication device. 

Difference between asymmetric and symmetric encryption.

Symmetric encryption requires the same key for encryption and decryption. On the other hand, asymmetric encryption needs different keys for encryption and decryption.

Full form of XSS ? 

 XSS stands for cross-site scripting. 

Explain WAF:- WAF stands for Web Application Firewall. WAF is used to protect the application by filtering and monitoring incoming and outgoing traffic between web application and the internet.

What is Hacking exactly ?  Hacking is a process of finding weakness in computer or private networks to exploit its weaknesses and gain access.

For example, using password cracking technique to gain access to a system.

Who are  called hackers ?

A Hacker is a person who finds and exploits the weakness in computer systems, smartphones, tablets, or networks to gain access. Hackers are well experienced computer programmers with knowledge of computer security. 

What is network sniffing ?

Network sniffing is a tool used for analyzing data packets sent over a network. This can be done by the specialized software program or hardware equipment. Sniffing can be used to:

Capture sensitive data such as password.

Eavesdrop on chat messages

Monitor data package over a network

 Importance of DNS monitoring ?

Yong domains are easily infected with malicious software. You need to use DNS monitoring tools to identify malware.

Process of salting. What is the use of salting ?

Salting is that process to extend the length of passwords by using special characters. To use salting, it is very important to know the entire mechanism of salting. The use of salting is to safeguard passwords. It also prevents attackers testing known words across the system.

For example, Hash("QxLUF1bgIAdeQX") is added to each and every password to protect your password. It is called as salt.

What is SSH ?

SSH stands for Secure Socket Shell or Secure Shell. It is a utility suite that provides system administrators secure way to access the data on a network.

 SSL protocol in network security.

SSL verifies the sender's identity, but it does not provide security once the data is transferred to the server. It is good to use server-side encryption and hashing to protect the server against a data breach.

black box testing and white box testing.

Black box testing: It is a software testing method in which the internal structure or program code is hidden.

White box testing: A software testing method in which internal structure or program is known by tester.

Major vulnerabilities in network security.

Vulnerabilities refer to the weak point in software code which can be exploited by a threat actor. They are most commonly found in an application like SaaS (Software as a service) software.

 TCP Three-way handshake.

It is a process used in a network to make a connection between a local host and server. This method requires the client and server to negotiate synchronization and acknowledgment packets before starting communication.

 The term residual risk, What are three ways to deal with risk ?

It is a threat that balances risk exposure after finding and eliminating threats.

Three ways to deal with risk are:

  • Reduce it 
  • Avoid it
  • Accept it.

Define Exfiltration.

Data exfiltration refers to the unauthorized transfer of data from a computer system. This transmission may be manual and carried out by anyone having physical access to a computer.

Exploit in network security?

An exploit is a method utilized by hackers to access data in an unauthorized way. It is incorporated into malware.

Penetrating testing ?

It is the process of checking exploitable vulnerabilities on the target. In web security, it is used to augment the web application firewall.s

 Common cyber-attack.

Following are the common cyber-attacks which can be used by hackers to damage network:

  • Malware
  • Phishing
  • Password attacks
  • DDoS
  • Man in the middle
  • Drive-by downloads

Malvertising - (Malvertising is the use of online advertising to spread malware) Rogue software

User authentication process.

In order to authenticate users, they have to provide their identity. The ID and Key can be used to confirm the user's identity. This is an ideal way how the system should authorize the user. concept of cross-site scripting.

Cross-site scripting

Cross-site scripting refers to a network security vulnerability in which malicious scripts are injected into websites. This attack occurs when attackers allow an untrusted source to inject code into a web application.

Name the protocol that broadcast the information across all the devices.

Internet Group Management Protocol or IGMP is a communication protocol that is used in game or video streaming. It facilitates routers and other communication devices to send packets.

Way to protect email messages ?

Use cipher algorithm to protect email, credit card information, and corporate data.

Risks associated with public Wi-Fi network.

Public Wi-Fi has many security issues. Wi-Fi attacks include karma attack, sniffing, war-driving, brute force attack, etc.

Public Wi-Fi may identify data that is passed through a network device like emails, browsing history, passwords, and credit card data.

Data Encryption, Why it is important in network security ?

Data encryption is a technique in which the sender converts the message into a code. It allows only authorized user to gain access.

 Main difference between Diffie-Hellman and RSA.

Diffie-Hellman is a protocol used while exchanging key between two parties while RSA is an algorithm that works on the basis two keys called private and public key.

Remote access desktop protocol.

Remote Desktop Protocol (RDP) is developed by Microsoft, which provides GUI to connect two devices over a network, the user uses RDP client software to serve this purpose while other device must run RDP server software. This protocol is specifically designed for remote management and to access virtual PCs, applications, and terminal server.

What is Forward Secrecy?

Forward Secrecy is a security measure that ensures the integrity of unique session key in event that long term key is compromised.

The concept of IV in encryption.

IV stands for the initial vector is an arbitrary number that is used to ensures that identical text encrypted to different ciphertexts. Encryption program uses this number only once per session.

Main difference between stream cipher and block cipher.

Parameter Stream Cipher Block Cipher.

Stream cipher operates on small plaintext units Block cipher works on large data blocks. Code requirement It requires less code. It requires more code.
Usage of key Key is used only once.Reuse of key is possible.
Application Secure Socket layer. File encryption and database.
Usage Stream cipher is used to implement hardware. Block cipher is used to implement software.

 Abbreviation of ECB and CBC

The full form of ECB is Electronic Codebook, and the full form of CBC is Cipher Block Chaining.

Buffer overflow attack.

Buffer overflow attack is an attack that takes advantage of a process that attempts to write more data to a fixed-length memory block.


Spyware is a malware that aims to steal data about the organization or person. This malware can damage the organization's computer system.

What is impersonation 

It is a mechanism of assigning the user account to an unknown user.

What is SRM?

SRM stands for Security Reference Monitor provides routines for computer drivers to grant access rights to object.

About computer virus.

A virus is a malicious software that is executed without the user's consent. Viruses can consume computer resources, such as CPU time and memory. Sometimes, the virus makes changes in other computer programs and insert its own code to harm the computer system.
A computer virus may be used to:
Access private data like user id and passwords
Display annoying messages to the user
Corrupt data in your computer
Log the user's keystrokes

What do you mean by Authenticode?

Authenticode is a technology that identifies the publisher of Authenticode sign software. It allows users to ensure that the software is genuine and not contain any malicious program.

Define CryptoAPI

CryptoAPI is a collection of encryption APIs which allows developers to create a project on a secure network.

Steps to secure web server.

Follow the following steps to secure your web server:
Update ownership of file.
Keep your webserver updated.
Disable extra modules in the webserver.
Delete default scripts.

Microsoft Baseline Security Analyzer.

Microsoft Baseline Security Analyzer or MBSA is a graphical and command-line interface that provides a method to find missing security updates and misconfigurations.

What is Ethical hacking?

Ethical hacking is a method to improve the security of a network. In this method, hackers fix vulnerabilities and weakness of computer or network. Ethical hackers use software tools to secure the system.

Explain social engineering and its attacks.

Social engineering is the term used to convince people to reveal confidential information. There are mainly three types of social engineering attacks: 1) Human-based, 2) Mobile-based, and 3) Computer-based. Human-based attack: They may pretend like a genuine user who requests higher authority to reveal private and confidential information of the organization. Computer-based attack: In this attack, attackers send fake emails to harm the computer. They ask people to forward such email. Mobile-based attack: Attacker may send SMS to others and collect important information. If any user downloads a malicious app, then it can be misused to access authentication information.

What is IP and MAC Addresses?

IP Address is the acronym for Internet Protocol address. An internet protocol address is used to uniquely identify a computer or device such as printers, storage disks on a computer network.
MAC Address is the acronym for Media Access Control address. MAC addresses are used to uniquely identify network interfaces for communication at the physical layer of the network.

What do you mean by a worm ?

A Worm is a type of malware which replicates from one computer to another.

Difference between virus and worm 
How they infect a computer ?

It inserts malicious code into a specific file or program. Generate it's copy and spread using email client. Dependency Virus need a host program to work They do not require any host to function correctly.

It linked with files It is linked with .com, .xls, .exe, .doc, etc. It is linked with any file on a network. Affecting speed It is slower than worm. It faster compared to a virus.

Tools used for packet sniffing.

Following are some tools used for packet sniffing.
  • Tcpdump
  • Kismet
  • Wireshark
  • NetworkMiner
  • Dsniff
 Anti-virus sensor systems

Antivirus is software tool that is used to identify, prevent, or remove the viruses present in the computer. They perform system checks and increase the security of the computer regularly.

Types of sniffing attacks.
Various types of sniffing attacks are:
  • Protocol Sniffing
  • Web password sniffing
  • Application-level sniffing
  • TCP Session stealing
  • LAN Sniffing
  • ARP Sniffing 

  • What is a distributed denial-of-service attack (DDoS)?
It is an attack in which multiple computers attack website, server, or any network resource.

 Concept of session hijacking.

TCP session hijacking is the misuse of a valid computer session. IP spoofing is the most common method of session hijacking. In this method, attackers use IP packets to insert a command between two nodes of the network.

 Methods of session hijacking.

Various methods of session hijacking are:
  • Using packet Sniffers
  • Cross-Site Scripting (XSS Attack)
  • IP Spoofing
  • Blind Attack
Popular hacking Tools.

Hacking Tools are computer programs and scripts that help you find and exploit weaknesses in computer systems, web applications, servers, and networks. There are varieties of such tools available on the market. Some of them are open source, while others are a commercial solution.

Explain honeypot and its Types.

Honeypot is a decoy computer system which records all the transactions, interactions, and actions with users.
Honeypot is classified into two categories: 1) Production honeypot and 2) Research honeypot. Production honeypot: It is designed to capture real information for the administrator to access vulnerabilities. They are generally placed inside production networks to increase their security.
Research Honeypot: It is used by educational institutions and organizations for the sole purpose of researching the motives and tactics of the back-hat community for targeting different networks.

Name common encryption tools.

Tools available for encryptions are as follows:
  • RSA
  • Twofish
  • AES
  • Triple DES
What is Backdoor.

It is a malware type in which security mechanism is bypassed to access a system.

Explain the 80/20 rule of networking.

This rule is based on the percentage of network traffic, in which 80% of all network traffic should remain local while the rest of the traffic should be routed towards a permanent VPN.

Define WEP cracking.

It is a method used for a security breach in wireless networks. There are two types of WEP cracking: 1) Active cracking and 2) Passive cracking.

Popular WEP cracking tools.

Well known WEP cracking tools are:
  • Aircrack
  • WebDecrypt
  • Kismet
  • WEPCrack
 What is a security auditing?

Security auditing is an internal inspection of applications and operating systems for security flaws. An audit can also be done via line by line inspection of code.

 Explain phishing.

It is a technique used to obtain a username, password, and credit card details from other users.

What is Nano-scale encryption?

Nano encryption is a research area which provides robust security to computers and prevents them from hacking.

 Define Security Testing?

Security Testing is defined as a type of Software Testing that ensures software systems and applications are free from any vulnerabilities, threats, risks that may cause a big loss.

What is Security Scanning?

Security scanning involves identifying network and system weaknesses and later provides solutions for reducing these risks. This scanning can be performed for both Manual as well as Automated scanning.

Famous hacking tools.

Following is a list of useful hacking tools.
  • Acunetix
  • WebInspect
  • Probably
  • Netsparker
  • Angry IP scanner:
  • Burp Suite
  • Savvius
Importance of penetration testing in an enterprise.

Here are two common application of Penetration testing.
Financial sectors like stock trading exchanges, investment banking, want their data to be secured, and penetration testing is essential to ensure security. In case if the software system is already hacked and the organization would like to determine whether any threats are still present in the system to avoid future hacks.

Disadvantages of penetration testing.

Disadvantages of penetration testing are:
Penetration testing cannot find all vulnerabilities in the system.
There are limitations of time, budget, scope, skills of penetration testers.
Data loss and corruption Down Time is high which increase costs.

What is security threat.

Security threat is defined as a risk which can steal confidential data and harm computer systems as well as organization.

What are physical threats?

A physical threat is a potential cause of an incident that may result in loss or physical damage to the computer systems.

 Examples of non-physical threats 

Following are some examples of non-physical threat: Loss of sensitive information Loss or corruption of system data Cyber security Breaches Disrupt business operations that rely on computer systems Illegal monitoring of activities on computer systems.

 What is Trojan virus?

Trojan is a malware employed by hackers and cyber-thieves to gain access to any computer. Here attackers use social engineering techniques to execute the trojan on the system.

Define SQL Injection

It is an attack that poisons malicious SQL statements to database. It helps you to take benefit of the design flaws in poorly designed web applications to exploit SQL statements to execute malicious SQL code. In many situations, an attacker can escalate SQL injection attack in order to perform other attack, i.e. denial-of-service attack.

Security vulnerabilities as per Open Web Application Security Project (OWASP). 

Security vulnerabilities as per open web application security project are as follows:
  • SQL Injection
  • Cross-site request forgery
  • Insecure cryptographic storage
  • Broken authentication and session management
  • Insufficient transport layer protection
  • Unvalidated redirects and forwards
  • Failure to restrict URL access
 Define an access token

An access token is a credential which is used by the system to check whether the API should be granted to a particular object or not.

 ARP Poisoning

ARP (Address Resolution Protocol) Poisoning is a type of cyber-attack which is used to convert IP address to physical addresses on a network device. The host sends an ARP broadcast on the network, and the recipient computer responds back with its physical address. ARP poisoning is sending fake addresses to the switch so that it can associate the fake addresses with the IP address of a genuine computer on a network and hijack the traffic.

Non-physical threats

Following are various types of non-physical threats:
  • Trojans
  • Adware
  • Worms
  • Spyware
  • Denial of Service Attacks
  • Distributed Denial of Service Attacks
  • Virus
  • Key loggers
  • Unauthorized access to computer systems resources
  • Phishing

Sequence of a TCP connection.

The sequence of a TCP connection is SYN-SYN ACK-ACK.

What is hybrid attacks.

Hybrid attack is a blend of dictionary method and brute force attack. This attack is used to crack passwords by making a change of a dictionary word with symbols and numbers.

What is Nmap?

Nmap is a tool which is used for finding networks and in security auditing.

Usage of EtterPeak tool ?

EtterPeak is a network analysis tool that is used for sniffing packets of network traffic.

Types of cyber-attacks.

There are mainly two types of cyberattacks: 
1) Web-based attacks,
2) System based attacks.

web-based attacks

Some web-based attacks are:
1) SQL Injection attacks, 
2) Phishing, 3) Brute Force, 4) DNS Spoofing, 4) Denial of Service, and 5) Dictionary attacks.

System-based attacks

Examples of system-based attacks are:
  • Virus
  • Backdoors
  • Bots
  • Worm
Types of cyber attackers. 

1) cybercriminals, 
2) hacktivists,
3) insider threats, 
4) state-sponsored attackers.

Accidental threats

Threats that are accidently done by organization employees. In these threats, an employee unintentionally deletes any file or share confidential data with outsiders or a business partner going beyond the policy of the company.

Learning Reference Resources of cyber security Courses Certificates. 

mrtg installation and configuration on centos linux

Now install MRTG and configure fast and easy steps guide for installation and configuration on centos. 

Linux based Multi Router Traffic Grapher installation guide on your Linux box.

Multi Router Traffic Grapher - MRTG is a powerful tool to monitor your organization network  traffic load live on network links. MRTG tool generates HTML (Hyper Text Markup Language) based web pages containing .PNG images files which helps you to provide a LIVE visual, graphical  representation of your running network traffic. now we can follow few easy steps to know how to install & configure Multi Router Traffic Grapher on the Cent OS Linux platform, we can use these easy steps in any our Linux distributions to complete the steps. 

Step 1. install the Apache web server using yum 

#yum -y install httpd

#service httpd restart

Step2. Install MRTG using through YUM package manager 

#yum -y install net-snmp mrtg net-snmp-utils

Step3. Configure the SNMP

#vi /etc/snmp/snmpd.conf

#mv /etc/snmp/snmpd.conf /etc/snmp/snmpd.conf-bak

#cd /etc/snmp/

#vi snmpd.conf

rocommunity public

syslocation "My Server Room"

syscontact Root <>

Now Save the Configuration

Step4. Restart the snmpd service

Step5. now to check the status

#snmpwalk -v2c -c public localhost system

Once done then configure the MRTG configure

Step6. Include your server IP on cfgmaker

#cfgmaker --snmp-options=:::::2 --ifref=descr --ifdesc=descr --global 'WorkDir: /var/www/html/mymrtg' public@ > /etc/mrtg/mrtg.cfg

Step7. Create the index file

#cd /var/www/html/

#mkdir mymrtg

#indexmaker --columns=1 /etc/mrtg/mrtg.cfg > /var/www/html/mymrtg/index.html

Step8. Configure mrtg.conf

#vi /etc/httpd/conf.d/mrtg.conf

Just only add the Alias and remove the remaining entries.

Alias /mrtg /var/www/html/mymrtg

Step9 . Restart the httpd service

#service httpd restart

#service snmpd restart

Yes now complete the installation we can run and test on your browser.

cyber security awareness | information assurance |

Cyber security awareness | information assurance | Education 

शाम को एक call आई, कोई लड़की थी बोली,” सर, मैं जॉब के लिए रजिस्ट्रेशन कर रही थी । गलती से आपका नम्बर डाल दिया है, क्योकि मेरे और आपके मोबाइल नंबर में काफी समानता है । आपके पास थोड़ी देर में एक ओटीपी (OTP) आएगी, प्लीज बता दो सर, मेरी ज़िन्दगी का सवाल है।

चूँकि बात बिल्कुल सही लग रही थी, मैनें मोबाइल इनबॉक्स (inbox) चेक किया, दो मैसेज (message) आए हुए थे। एक पर ओटीपी था, दूसरा एक मोबाइल से आया मैसेज। लिखा था; “dear सर, आपके पास जो ओटीपी आयी है, प्लीज इस नंबर पर भेज दीजिये…Thanks in advance.”

मैं बोला, “बता दूंगा, पर आप पहले एक काम करो..

हाँ सरबोलिए..

जो नंबर आपने रजिस्ट्रेशन में डाला है, वो मेरा नम्बर है और उसी से मिलता-जुलता नम्बर आपके पास भी है, तभी आपसे ये गलती हुई, है न?”

हाँ सर..

ओके, उसी नम्बर से मुझे आप कॉल करो, ताकि मैं वेरीफाई (verify) कर सकूँ कि आप सही हो..

वो क्या है सर, उस नम्बर में बैलेंस नही है। सरएक लड़की की बात पर आपको भरोसा नही…?”

बात लड़की, लड़के और भरोसे की नही है। मैं आपको नही जानता, तो फिर बिना जांचे-परखे कैसे भरोसा कर लूँ…”

तो फिर रहने दीजिएआप जैसे कठोर लोगों की वजह से ही आज मानवता से लोगों का भरोसा उठ गया है ।

एक-दो कठोर शब्दों के साथ उस सुमधुर कर्कशा ने फोन काट दिया।

तभी मेरे बैंक का ईमेल का नोटिफिकेशन स्क्रीन पर फ़्लैश हुआ । बैंक का नोटिफिकेशन में लिखा था;

"Dear Sir/Madam,

You are trying to change your internet banking password, click the link below…

जैसी मुझे उम्मीद थी वही हुआमानवता के नाम पर भी इतनी ठगबाज़ीधोखेबाज़ी

मुझे RESULT पता था फिर भी नंबर रीडायल किया तो उधर से जवाब आया

The customer, you are trying to reach is not available…

जैसा कि मैंने अपनी बहुत से पोस्ट में लोगो को हैकिंग और साइबर क्राइम से बचाव के बारे बताया है वैसे ही बताना चाहूंगा कि वास्तव में इस हैकिंग ट्रिक में हैकिंग की दो तकनीक का प्रयोग किया जा रहा था फिशिंग और विशिंग। फिशिंग के द्वारा आपको अपने जाल में फसाया जाता है और विशिंग में आप अपनी इच्छा से हैक होने के लिए जानकारियां शेयर कर देते हैं।

इसलिए ख़ुद सावधान रहें-औरों को सचेत करें"


remote jobs near me us uk india from home

Remote jobs near me us, uk, India work from home. 

A remote job is one for which you do not need to be present in an office or physical location on a daily basis.


Remote jobs can be done from home or anywhere with a Wi-Fi internet  connection or other digital tools.

Sometimes, any company allows workers to work from home a certain number of days per week, while other companies are 100% remote, which means that all work is decentralized now.

Working a remote job still requires you to perform the same duties as you would in a traditional job, but your responsibilities include being independent, managing your time wisely, and remaining on task without immediate oversight.

Here I am listing some of the best platform where one can find and apply for it. 


We Work Remotely is the largest remote work community in the world. With over 2.5M monthly visitors, WWR is the #1 destination to find and list incredible remote jobs.


Experience the startup ecosystem — invest in startups, research the fastest-growing companies, and find a job you love.


Remote jobs for Digital Working Nomads. Work remotely from your home or places around the world.


All Things Remote Work, 142 leading remote companies and virtual teams answer your top questions about remote work.


Indeed is an American worldwide employment website for job listings launched in November 2004. It is a subsidiary of Japan's Recruit Co. Ltd. and is co-headquartered in Austin, Texas and Stamford, Connecticut with additional offices around the world.


We help you find them. We curate & train developers to qualify silicon valley standards.

Cyber Security Salary Jobs Interview Questions Certificate

Detail info about Cyber Security | How Cyber Security affect us | Useful tips for Cyber security awareness in our day to day life. 

Cyber Security related detail information such as Cyber Security Related Salary, Jobs, Interview Questions answers, Certificate.

साइबर सुरक्षा सम्बंधित संपूर्ण जानकारी | वेतन, नौकरियां, साक्षात्कार, सम्बंधित प्रश्न, उत्तर, प्रमाण पत्र |

According to the BLS, cyber security a
nalysts pulled in a median annual wage of $98,350 in 2018. Pay Scale, on the other hand, reports that those in the field make an average salary of $75,746 per year, with salaries ranging from as low as $51,000 to as high as $117,000.

बीएलएस के अनुसार, साइबर सुरक्षा विश्लेषकों ने 2018 में $ 98,350 के औसत वार्षिक वेतन में  लिया। वेतनमान, दूसरी ओर, रिपोर्ट करता है कि क्षेत्र में उन लोगों का औसत वेतन $ 75,746 प्रति वर्ष है, जिसमें वेतन $ 51,000 से कम है। $ 117,000 के रूप में उच्च के रूप में।

The average salary of experienced penetration testers is $55,000 while cybersecurity engineers make up to $140,000. If your skills are somewhere in the middle then you can be an analyst and get paid $80,000. Cybersecurity engineers are like regular coders but with a few extra tools in their toolbelts.

अनुभवी प्रवेश परीक्षकों का औसत वेतन $55,000 है जबकि साइबरसिटी के इंजीनियर 

$140,000 तक हैं। यदि आपका कौशल कहीं बीच में है तो आप एक विश्लेषक हो सकते हैं और $80,000 का भुगतान कर सकते हैं। साइबर स्पेस इंजीनियर नियमित कोडर की तरह होते हैं लेकिन उनके टूलबेल में कुछ अतिरिक्त उपकरण होते हैं।

crontab rsync Linux Command with key-gen

Easy way to setting crontab, rsync on linux steps and  commands with ssh-keygen backup purpose. 

What is Cron ? 

Cron is a software utility known as "cron job" it's a time, date based job scheduler in Unix Linux server, client operating systems. Users can set up and maintain software environments with the use of cron to schedule their jobs to run periodically at any fixed times, dates, month, year format.

The crontab is a command that you want to run on a regular schedule, used to manage cron jobs, Crontab stands for "cron table".

What is rsync :- 

Rsync is a powerful synchronization tool, this tool allows you to copy and delete data. 

rsync is also a software utility for efficiently transferring and synchronizing data files between a servers and clients computer and an external hard drive and across networked computers by comparing the modification times and sizes of files. 

It is commonly found on Linux/ Unix operating systems. rsync is written in C programming language as a single threaded application program.

Some of the frequent used command in rsync : 

-a : archive mode, archive mode allows copying files recursively and it also preserves symbolic links, file permissions, user & group ownerships and timestamps

-h : human-readable, output numbers in a human-readable format

-v : verbose

-r : copies data recursively (but don’t preserve timestamps and permission while transferring data

-z : compress file data

#rsync /source path  /destination path

#rsync -v /home/user/test.tex  /home/test/backup

rsync command to copy sync data on remote machine 

#rsync -av /var/www/html/user-data  user2@

this command will ask for your password to perform the task.

We can use this to execute on regular basis to take backup daily using "crontab" 

How to automatically run script using "crontab" 

Just go ahead and save this above command in a script file and make it executable. 

To add a crontab job, type the following command at a UNIX/Linux shell prompt:

# crontab -e

#Add the following line:

#1(min) 2(hours) 3(day) 4(month) 5(Day of the week



1: Minutes (0-59)

2: Hours (0-23)

3: Days (1-31)

4: Month (1-12)

5: Day of the week(1-7)

/script/file/path - on your shell script

for example suppose if you wish to run your backup script at 11:50PM IST.

# crontab -e

#Add this following line:

50 23 * * * /root/

Here the first entry indicates for minute and second for hour and next all * indicates for daily between (1-31 days), (1-12 Month), (1-7 Day of the week). 

In this case we also have to make sure that between source to destination machine the communication must be password less, to make it password less click here this link.