Malware is the combination of two words i.e malicious + software.
software: software is a piece of code or a script that is designed to perform a particular task and if that software is made to full fill his/her intention then that is malicious software.
Malware can infect any system by being bundled with any system or attached with any file. An attacker can infect any system, network, or any devices by finding any vulnerability in those and installing Malware Threats on them.
also by social engineering where a person clicks on some link or mail and behind it the malware gets execute.
Purpose of Malware Threats:
- Files Steal
- encryption or deleting sensitive data
- spy
- corrupt system/application/
- tamper normal working of a system/app/
- misuse system resources–RAM/CPU/STORAGE
- user activity(online/offline)monitor–browser/desktop surf/files/view/
- user keystrokes monitor
- extort money–after infecting your system they can ask you for money saying that he will resolve it.
How malware spreads?
- Free software:
People don’t want to buy the software so what they do is they download from any insecure sites, and in that software hacker bind their malware…and once it’s downloaded into the system then it can give access to the attacker with Malware Threats.
A hacker can also create a backdoor so that even after the uninstallation of software attacker can remotely access the victim system.
so that incorporate or in any organization, they don’t use free software.
- Email communications:
An attacker can act like anyone, he acts as an organization and sent you the mail saying that they are hiring u and paying you that much of amount, and with that mail, he has sent u the pdf saying that go through this pdf so that u can have more brief info.
but that pdf came with the malware, so once u open that pdf at the same time the malware gets executed and can compromise your system.
- Removal devices:
suppose an attacker asked you for any files and asked u to provide him..and also asked you if he uses his pen drive to get the file
and u allow him to and through that Pendrive, an attacker can leave his Malware Threats and can compromise your system.
E.g.: rubber ducky USB(it send 1000 command per sec)it can steal your SAM file and also passwords from the chrome.
Types of Malware:
- Virus
- Worms: Stuxnet, Snowden movie
- Trojan horse
- Ransomeware
- Rootkit
- Spyware
- Keylogger: REFOG
1. Virus:
It requires human interaction to spread the infection.
like through: USB/email attachment/harmful/
user’s click is required.
Indication of Virus:
- BSOD(Blue Screen of Death)
- System will be slow
- Unnecessary files will run in the background
Types of Virus:
1. boot sector virus:
Our hard drive is divided into sectors and their first sector is MBR(Master Boot Record).
MBR contains the information that what OS is our PC using and boot our system as it contains boot loader.
So, when our system gets infected with a boot sector virus then the place MBR virus gets placed and moves the MBR into the next sector.
so whenever we power on then at very first virus gets executed instead of MBR and our system will not boot and for that, we need to format all
and reboot our system with the new OS.
2. File virus:
Comes with .exe file when we execute .exe
a virus will be executed.
3. Macro virus:
Mainly target ms office, A virus written in
VBS(Visual Basics script)
4. Cluster virus:
Ties itself with any executable and whenever we open that .exe
The virus will get executed.
5. stealth virus:
Try to hide and avoid being detected by antivirus (FUD) fully undetectable virus.
6. Logic bomb:
It will execute at a given date and time.
7. Encryption virus:
Encrypt itself to avoid identified by antivirus.
8. Metamorphic virus:
Can be able to change its code and signatures to be able to
undetectable by antivirus.
9. Shell virus:
It will be executed inside a shell (the shell is the deepest part of the system)
Make a Virus:
: test
MD test
cd test
goto test
save as .bat and double click on the file to execute.
: test
start calc, start notepad
start MSPaint
save as .bat and double click on the file to execute.
: test
MD %random%
goto test
Notes: Virus total is the website where we can detect our files or anything, and it runs 60 to 70 anti-virus to detect if they contain any malware.
2. Types of Trojan:
- Defacement trojan:
after compromising any website or system, the hacker displays the
any black blue or any color on your screen and leave the msg there
like u have been hack.
- HTTP and HTTPS Trojan:
They target web applications.
- RAT(Remote access trojan):
you can remotely access the computer.
3. ROOTKIT:
Rootkit tools:
- Horse pill (Linux)
- Gray fish (Windows)
- Sirefef
- Necurs
4. SPYWARE:
Spyware is use to detect what the victim is searching, which website he is visiting, how much time he is spending on a particular site.
5. Keylogger:
It is use to detect your keyboard, whatever you give the input through your keyboard all will be detect by the hacker.
Files that are executable in Windows:
- Bat: batch file
- Bin: binary executable
- Cmd: command script
- Exe: executable
- Com: command file
Article By: Sayan Chatterjee
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