Different types of malware

    • Unwanted advertising in the browser
    • Call to downloading shareware and freeware
    • Disguises itself as a standard program but has malware embedded in the background
    • Annoying advertising while surfing on internet

    • Observes the system and network
    • Monitors activities as well as conversations by using the microphone and camera from the user
    • Sends user data to third parties and hackers
    • Uses data to produce user specific advertisement

Most interesting data:

    1. Registration data
    2. Credit card numbers, financial details
    3. Secret conversations
    4. Browsing history
    5. Search history

    • A virus attaches itself to a program or file
    • Requires action from the user
      → It waits passively to be spread onto a new system
    • Virus copies itself while program is running
    • Virus infects other programs with malicious code
    • Programs infect other standard programs on the computer (snowball system)
    • Changes, damages or destroys personal data
    • Damages hardware

    • Programs that make countless copies of themselves
    • Similar to a virus but they can be transmitted without a person's action
    • Spread through networks and gaps of operating systems
    • Stay active in infected devices

    • Acts like a reputable program
    • Performs another function in the background unnoticed
    • By executing the program, attackers get access rights to the system and personal data
    • Attackers install more malware, execute programs or publish personal data

    • Revokes access rights
    • Blocks important files
    • Demands ransom to get back access rights (usually in bitcoins)

    • Method to steal the user’s identification and passwords illegally trough fake SMS and mails
    • Attackers “fish” for access data
    • Usage of a professional form (E-mails from the bank)
    • Focus is on data for online banking , online shops and social networks
    • Attackers receive a new identity (the identity of the user)

How to identify phishing mails?

      • Grammar and spelling mistakes
      • Use of foreign language (English or French)
      • No personal approach but “Dear customer”
      • Urgent need for action (especially in a short term)
      • Call for personal and secret information
      • Request to open an unknown attachment
      • Suspect links which need to be opened
      • Unknown addressor

In most cases, banks are affected. Therfore, attention needs to be payed to the banks name and the responsible bank advisor.


    • Access method from the “backdoor”
    • Software with security gaps

→ Could be installed by a manufacturer consciously or a malware secretly

Allows external users to access the system remotely

    1. Through gaps
    2. By avoiding a security mechanism (like a login)

    • DOS = Denial of Service (one attacker)
    • DDOS = Distributed Denial of Service (more attackers or infected computers)
    • Attackers make servers or services unavailable

→ Overloading the system by sending multiple requests

→ Exceeding the website’s capacity

→ Crashing the website

    • Requests are much slower or ignored
    • Main aim: Preventing users from accessing the target page
    • Known victims are Amazon and eBay

    • Distributed computing network (technical view)
    • Network of computers that execute malware automatically
    • Attackers access to the computers remotely
    • Botnets only work while the computer is running and part in a network
    • In most cases botnets are used for criminal activities…

    1. Act like distributed centers to send fake e-mails (Phishing)
    2. Provide remote access to foreign systems so that personal information can be sold (ex. In the Darknet)
    3. Get a lot of memory storage for destructive data files
    4. Build connection to other computers to hide the origin address

How do botnets work?

    1. Users with an undamaged but unprotected system call to infected website
    2. On this manipulated website they catch malware
    3. The infected computers (called “Bots” now) become part of a network of more controlled computers
    4. After that, these computers receive commands from hackers (botmasters)
    5. They do communicate with each other but work independently
    6. Bots obey the tasks from the hacker

Last modified: Monday, 15 March 2021, 3:56 PM