Showing posts with label Virus. Show all posts
Showing posts with label Virus. Show all posts

Tuesday, 14 April 2015

What is Cross Site Scripting?

Cross-Site Scripting Attacker inserts malicious code into an application, when regular users request the webpage it returns the malicious page and the attacker gains control over user data via code he injects.

Countermeasure

Safely validating untrusted HTML input

Cookie security

Disabling scripts

Tuesday, 7 April 2015

What is Dictionary Attacks?

 


A dictionary attack is a brute-force technique where attackers run through common words and phrases, such as those from a dictionary, to guess passwords. It is also known as dictionary password attack. 

Most people use real words as passwords.

Trying all dictionary words and makes the attack much faster.

Hackers and spammers attempt to log in to a computer system by trying all possible passwords until the correct one is found.

Countermeasures

Lockout a user after X no of  failed login attempts

Not using Dictionary words as passwords

Tuesday, 24 March 2015

What is Fraggle Attacks?

 

A Fraggle attack is exactly the same as a smurf attack, except that it uses the user datagram protocol, or UDP, rather than the more common transmission control protocol, or TCP. Fraggle attacks, like smurf attacks, are starting to become outdated and are commonly stopped by most firewalls or routers.

The attacker sends UDP packets to the random ports of the victim host. The victim will check for application listening on the port and reply with the "ICMP destination unreachable" packet.

The attacker can spoof the IP address of the UDP packets so that no one can trace it back.

Countermeasures

Close all unused ports.


Saturday, 14 March 2015

What is Smurf Attack?

 


A smurf attack is a form of a distributed denial-of-service attack that renders computer networks inoperable

The Smurf program accomplishes this by exploiting vulnerabilities of the Internet Protocol (IP) and Internet Control Message Protocols (ICMP).

Huge numbers of ICMP requests are sent to the victim's IP address.

The source and destination IP address is spoofed. The hosts on the victim's network respond to the ICMP requests.

This creates a significant amount of traffic on the victim’s network, resulting in the consumption of bandwidth and ultimately causing the victim’s server to crash.

Countermeasures

Configure individual hosts and routers to not respond to ICMP requests or broadcasts; or

Configure routers to not forward packets directed to broadcast addresses.

Friday, 6 March 2015

What is Brute Force Attack?

Brute Force Attack

A brute-force attack consists of an attacker trying many passwords or passphrases with the hope of eventually guessing correctly.

The attacker systematically checks all possible passwords and passphrases until the correct one is found.

When password guessing, this method is very fast when used to check all short passwords.

There is a computer program run automatically to get the password.

The most basic brute force attack is a dictionary attack, where the attacker works through a dictionary of possible passwords and tries them all.

Countermeasures

• Account Lockout - You Have Implemented Account Lockout With A Clipping Level Of 4

• Strong Passwords -  A strong password must be at least 12 characters long and should consist of a random collection of uppercase and lowercase letters, numbers, and special characters.

• Implement Captcha - It is used to differentiate between real users and automated users, such as bots.


Friday, 20 February 2015

What is Man-In-The-Middle Attack?

 

Man-In-The-Middle Attack AKA MITM

It is an attack where the attacker secretly relays and possibly alters the communication between two parties who believe they are directly communicating with each other.


Countermeasures

Digital Signature - A digital signature is a mathematical scheme for verifying the authenticity of digital messages or documents.

Mutual authentication - Mutual authentication, also known as two-way authentication, is a security process in which entities authenticate each other before actual communication occurs.

Friday, 6 February 2015

What is an Cyber Attack?

Cyber Attack

A cyber attack is an attempt to destroy, expose, alter, disable, steal or gain unauthorized access to or make unauthorized use of an asset. Without proper security measures and controls in place, our data might be subjected to an attack. 

Some attacks are passive, meaning information is monitored; others are active, meaning the information is altered with intent to corrupt or destroy the data or the network itself.

The attack is not only from the side of external individuals but, it is also from internal sources.

Sunday, 7 July 2013

What is a Computer Worm?

A computer worm is a self-replicating computer program that penetrates an operating system with the intent of spreading malicious code. Worms utilize networks to send copies of the original code to other computers, causing harm by consuming bandwidth or possibly deleting files or sending documents via email. Worms can also install backdoors on computers.

Example:
  • Melissa
  • ILOVEYOU


Source: http://www.pctools.com/

What is Polymorphic Virus?

They encode or encrypt themselves in a different way every time they infect your computer. They use different encryption and algorithms. This makes it difficult for the antivirus software to locate them using signature or string searches (since they are very different in each encryption).

Example:
  • Marburg
  • tuareg
  • Satan bug
  • elkern


Source: http://typeslist.com/

Friday, 28 June 2013

What is Companion Viruses?

These types of viruses infect files just like the direct action and the resident types. Once inside the computer, they ‘accompany’ other existing files.

Example:
  • Asimov.1539
  • stator and terrax.1069


Source: http://typeslist.com/

Friday, 14 June 2013

What is FAT Viruses?

These lardy viruses attack the file allocation table (FAT) which is the disc part used to store every information about the available space, location of files, unusable space etc.

Example:
  • the link virus


Source: http://typeslist.com/

Friday, 7 June 2013

What is Multipartite Virus?

These type of viruses spread in many different ways. Their actions vary depending on the OS installed and presence of certain files. They tend to hide in the computer’s memory but do not infect the hard disk.

Example:
  • flip
  • invader
  • tequila


Source: http://typeslist.com/

Tuesday, 28 May 2013

What is Memory Resident Viruses

They usually fix themselves inside the computer memory. They get activated every time the OS runs and end up infecting other opened files. They hide in RAM.
Example:
  • CMJ
  • meve
  • randex
  • mrklunky

Source: http://typeslist.com/

Tuesday, 21 May 2013

What is Web Scripting Virus?

Most web pages include some complex codes in order to create an interactive and interesting content. Such a code is often exploited to cause certain undesirable actions. They mostly originate from the infected web pages or browsers.

Example:
  • JS.Fortnight – a virus that spreads via malicious emails.



Source: http://typeslist.com/

Tuesday, 7 May 2013

What is Directory Viruses?

Also known as cluster virus or file system virus. They infect the computer’s directory by changing the path indicating file location. They are usually located in the disk but affect the entire directory.

Example:
  • dir-2 virus


Source: http://typeslist.com/

What is Overwrite Viruses?

These types of viruses delete any information in a file they infect, leaving them partially or completely useless once they are infected. Once in the computer, they replaces all the file content but the file size doesn’t change.

Example:
  • Trj.Reboot
  • way
  • trivial.88.D


Source: http://typeslist.com/

Sunday, 28 April 2013

What is Direct Action Viruses?

These viruses mainly replicate or take action once they are executed. When a certain condition is met, the viruses will act by infecting the files in the directory or the folder specified in the AUTOEXEC.BAT. The viruses are generally found in the hard disk’s root directory, but they keep on changing location.

Example:

  • Vienna virus

Source: http://typeslist.com/

What is Macro Viruses?

These viruses infect the files created using some applications or programs that contain macros such as doc, pps, xls and mdb. They automatically infect the files with macros and also templates and documents that are contained in the file. They hide in documents shared through e-mail and networks.

Example:
  • Relax
  • bablas
  • Melissa.A
  • 097M/Y2K

source: http://typeslist.com/

Types of Computer Viruses

  • Macro Viruses
  • Memory Resident Viruses
  • Overwrite Viruses
  • Direct Action Viruses
  • Directory Virus
  • Web Scripting Virus
  • Multipartite Virus
  • FAT Viruses
  • Companion Viruses
  • Polymorphic Virus
  • Worm
  • Trojans
  • Email Virus
  • Browser Hijacker
  • Boot Infectors

source: http://typeslist.com

Sunday, 21 April 2013

What is Computer Virus

A computer virus is a program or piece of code that is loaded onto your computer without your knowledge and runs against your wishes. Viruses can also replicate themselves. All computer viruses are man-made. A simple virus that can make a copy of itself over and over again is relatively easy to produce. Even such a simple virus is dangerous because it will quickly use all available memory and bring the system to a halt. An even more dangerous type of virus is one capable of transmitting itself across networks and bypassing security systems.

Source: http://www.webopedia.com

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