Page 532 - ComputerScience_Class_11

• Worms: A worm is a malicious, self-replicating program that spreads throughout a network without human
assistance. These worms consume large amounts of memory and bandwidth and thus affect the servers, networks
and the individual systems that they are often overloaded and stop responding.

• Trojan Horse: The Trojan horse is malware that disguises itself as a legitimate program. It is mainly sent as an
attachment in an email or as a free-to-download file. Once downloaded, it performs malicious tasks such as gaining
backdoor access to corporate systems, spying on users’ online activity or stealing sensitive data.
• Spyware: Spyware as the name itself suggests that this malware secretly records information about a user’s key
logging activities. Spyware could capture credit card/debit card details, email IDs and passwords which help cyber
criminals withdraw money from unknown accounts or access sensitive information which they may use with
malicious intent.

• Adware: It is an unwanted program that is installed without the user’s permission, but generally does not have any
criminal intentions. The main objective of adware is to advertise any product/service. But it slows down the system
considerably.

13.3 SPAM
Spams are unsolicited mails sent mainly with the idea of online business schemes or commercial advertisements,
which are sent in bulk to many recipients at once. They contain many fraudulent schemes which appear to be lucrative
choices for the users but which on opening may encounter malware such as worms, Trojan Horse, spyware, etc. This
would obviously be a threat to our computer systems as well as our user accounts held online. So, it is very essential
for the user to be aware of such spam emails.

Methods to separate spam emails from important ones are as follows:
• Using good Anti-Spam and Anti-Virus Software: This is the best way to get rid of spam. It not only marks those
spam emails but also protects the user’s account from various malware, which poses a threat to the computer
system.
• Always be sure about the sender and be careful while accessing his or her email: If we do not recognise any
email id or have some doubts regarding the sender of the email, then we should restrict ourselves from opening
it, as there might be a chance of spam. There are also some ways to recognise a spam email which are as follows:
♦ ♦Sometimes the email id does not match the name of the company or person who has sent it. For example,
suppose the sender is abc@gmail.com but the name displayed is “Gift from flipkart”.
♦ ♦ There might be spelling mistakes in the email ID. For example, abc@shopcues.in, here the domain name should
have been shopclues.in.

• Being ignorant about the tempting subjects: Always check the subject carefully before opening it. Sometimes,
the subject might sound very interesting such as “You have won 100000 dollars” or the sender might send some
information on some items that were never ordered. These are definitely the signs of being spam.

• Being alert about bank transactions: Request for updating any personal information in a bank or anything of that
sort. They might also ask the user to update credit card details or might give a threat of locking the credit card, etc.
Such spam mail should always be handled carefully as they are directly linked to the bank account.

Also, we should be careful before sharing our email IDs with unknown people.

13.4 PHISHING
Phishing refers to cybercrimes where spam email messages are sent to different people to get personal information
like usernames, passwords, card details, etc. In this case, the sender pretends to be a genuine official/company whose
mails look authentic enough to trick recipients into giving their sensitive personal information.

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