Computer virus
Chia sẻ bởi Nguyễn Ngọc Mỹ |
Ngày 07/05/2019 |
38
Chia sẻ tài liệu: Computer virus thuộc Tiếng Anh 8
Nội dung tài liệu:
Hello, can you guest what I mean
to you from these photos?
Hi, I’m W32.Blackmal.How are you?
1
Maybe you guessed correctly.
That is the topic which
we will introduce to you today.
2
COMPUTER VIRUS
Instructor: Trần Ngân Bình
Group 21:
1. Nguyễn Ngọc Mỹ 1050942
2. Nguyễn Mạnh Đạt 1040531
3. Lê Chí Hiện 1040544
3
SOME KEY TERMS
VIRUS: A program loaded onto your computer without your knowledge and runs against your wishes.
- TROJAN: A destructive program that masquerades as a benign application. Unlike viruses, Trojan don’t replicate themselves.
4
SOME KEY TERMS
WORM: A program or algorithm that replicates itself over a computer network and usually performs malicious actions.
- Blended threats combine the characteristics of viruses, worms, Trojan Horses, and malicious code with server and Internet vulnerabilities .
5
- COMPUTER VIRUS: A small program routine that infects a computer system & uses its resources to produce itself.
COMPUTER VIRUS-HOW TO WORKS?
Virus patches the operating system to detect program files. It then copies itself into these files.
6
MAIN PARTS OF A VIRUS
UNIFECTED PROGRAM
7
MAIN PARTS OF A VIRUS
8
MAIN PARTS OF A VIRUS
MISDIRECTION
9
MAIN PARTS OF A VIRUS
REPRODUCTION
REPRODUCTION ROUTINE allows virus to copy itself to other programs.
10
MAIN PARTS OF A VIRUS
TRIGGER
TRIGGER ROUTINE causes the payload to be activated at a particular time or when a particular event takes place.
11
MAIN PARTS OF A VIRUS
PAYLOAD
PAYLOAD ROUTINE may be a fairly harmless joke or may be very destructive.
12
WAY OF INFECTING
When the user runs an infected program, it is loaded into memory carrying the virus.
It can then use a reproduction routine to infect other programs.
13
WAY OF INFECTING
The virus may contain a payload that remains dormant until a trigger event activates it.
The payload might do something relatively harmless, or it might do something more destructive.
14
WAY OF INFECTING
When it infects a file, the virus replaces the first instruction in the host program with a command that changes the normal execution sequence.
The virus then returns control to the host program.
15
LEHIGH VIRUS
This is an example of a simple virus.
The infector portion of Lehigh replicates by attaching a copy of itself to COMMAND.COM and enlarging it by about 1000 bytes.
16
LEHIGH VIRUS
When you put a floppy containing COMMAND.COM into an infected PC, the infector of Lehigh looks over DOS’s shoulder & monitoring all floppy accesses.
When you tell the infected PC to access floppy drive, the Lehigh infector notices and adds a copy of itself to COMMAND.COM on the floppy.
17
LEHIGH VIRUS
If you take this floppy to another PC to boot, the virus will be installed in that PC.
Every time you access a hard disk subdirectory or a floppy disk containing COMMAND.COM, the virus sees that file and infects it.
18
LEHIGH VIRUS
Once Lehigh has infected 4 copies of COMMAND.COM, the detonator is triggered.
The detonator in Lehigh erases a vital part of hard disk, making the files on that part no longer accessible.
19
SOME WAYS OF INFECTING
Service people.
Pirated games.
Commercial softwares.
Putting floppies in public PCs without write-protect tabs.
Software distributed over computer bulletin board systems.
20
HOW TO AVOID VIRUSES?
Many viruses have spread through pirated-illegally copied or broken- games.
This is easy to avoid. Pay for your games, fair and square.
21
HOW TO AVOID VIRUSES?
If you use a public PC, be very careful about putting floppies into that PC’s drives without a write-protect tab.
Carry a virus-checking program and scan the PC before letting it write data onto floppies.
22
ANTIVIRUS PROGRAMS
There are actually 2 kinds of antivirus programs:
+ Virus shields: detect viruses as they are infecting your PC.
+ Virus scanners: detect viruses once they are infected.
- Some popular antivirus programs:
23
REMEMBER!
Viruses can’t infect a data or a text file.
Before running an antivirus program, be sure to cold-boot from a write-protected floppy.
Don’t boot from floppies except reliable DOS disks or your original production disks.
Stay away from pirated softwares.
24
REFERENCE
-Oxford English for Computing- Keith Boeckner & P. Charles Brown- Unit 7 page 78.
- Oxford English for Information Technology- Eric H. Glendinning & John MCEwan- Unit 18 page 124
25
THANK YOU VERY MUCH !
26
DO YOU HAVE
ANY QUESTION?
BYE NOW!
27
to you from these photos?
Hi, I’m W32.Blackmal.How are you?
1
Maybe you guessed correctly.
That is the topic which
we will introduce to you today.
2
COMPUTER VIRUS
Instructor: Trần Ngân Bình
Group 21:
1. Nguyễn Ngọc Mỹ 1050942
2. Nguyễn Mạnh Đạt 1040531
3. Lê Chí Hiện 1040544
3
SOME KEY TERMS
VIRUS: A program loaded onto your computer without your knowledge and runs against your wishes.
- TROJAN: A destructive program that masquerades as a benign application. Unlike viruses, Trojan don’t replicate themselves.
4
SOME KEY TERMS
WORM: A program or algorithm that replicates itself over a computer network and usually performs malicious actions.
- Blended threats combine the characteristics of viruses, worms, Trojan Horses, and malicious code with server and Internet vulnerabilities .
5
- COMPUTER VIRUS: A small program routine that infects a computer system & uses its resources to produce itself.
COMPUTER VIRUS-HOW TO WORKS?
Virus patches the operating system to detect program files. It then copies itself into these files.
6
MAIN PARTS OF A VIRUS
UNIFECTED PROGRAM
7
MAIN PARTS OF A VIRUS
8
MAIN PARTS OF A VIRUS
MISDIRECTION
9
MAIN PARTS OF A VIRUS
REPRODUCTION
REPRODUCTION ROUTINE allows virus to copy itself to other programs.
10
MAIN PARTS OF A VIRUS
TRIGGER
TRIGGER ROUTINE causes the payload to be activated at a particular time or when a particular event takes place.
11
MAIN PARTS OF A VIRUS
PAYLOAD
PAYLOAD ROUTINE may be a fairly harmless joke or may be very destructive.
12
WAY OF INFECTING
When the user runs an infected program, it is loaded into memory carrying the virus.
It can then use a reproduction routine to infect other programs.
13
WAY OF INFECTING
The virus may contain a payload that remains dormant until a trigger event activates it.
The payload might do something relatively harmless, or it might do something more destructive.
14
WAY OF INFECTING
When it infects a file, the virus replaces the first instruction in the host program with a command that changes the normal execution sequence.
The virus then returns control to the host program.
15
LEHIGH VIRUS
This is an example of a simple virus.
The infector portion of Lehigh replicates by attaching a copy of itself to COMMAND.COM and enlarging it by about 1000 bytes.
16
LEHIGH VIRUS
When you put a floppy containing COMMAND.COM into an infected PC, the infector of Lehigh looks over DOS’s shoulder & monitoring all floppy accesses.
When you tell the infected PC to access floppy drive, the Lehigh infector notices and adds a copy of itself to COMMAND.COM on the floppy.
17
LEHIGH VIRUS
If you take this floppy to another PC to boot, the virus will be installed in that PC.
Every time you access a hard disk subdirectory or a floppy disk containing COMMAND.COM, the virus sees that file and infects it.
18
LEHIGH VIRUS
Once Lehigh has infected 4 copies of COMMAND.COM, the detonator is triggered.
The detonator in Lehigh erases a vital part of hard disk, making the files on that part no longer accessible.
19
SOME WAYS OF INFECTING
Service people.
Pirated games.
Commercial softwares.
Putting floppies in public PCs without write-protect tabs.
Software distributed over computer bulletin board systems.
20
HOW TO AVOID VIRUSES?
Many viruses have spread through pirated-illegally copied or broken- games.
This is easy to avoid. Pay for your games, fair and square.
21
HOW TO AVOID VIRUSES?
If you use a public PC, be very careful about putting floppies into that PC’s drives without a write-protect tab.
Carry a virus-checking program and scan the PC before letting it write data onto floppies.
22
ANTIVIRUS PROGRAMS
There are actually 2 kinds of antivirus programs:
+ Virus shields: detect viruses as they are infecting your PC.
+ Virus scanners: detect viruses once they are infected.
- Some popular antivirus programs:
23
REMEMBER!
Viruses can’t infect a data or a text file.
Before running an antivirus program, be sure to cold-boot from a write-protected floppy.
Don’t boot from floppies except reliable DOS disks or your original production disks.
Stay away from pirated softwares.
24
REFERENCE
-Oxford English for Computing- Keith Boeckner & P. Charles Brown- Unit 7 page 78.
- Oxford English for Information Technology- Eric H. Glendinning & John MCEwan- Unit 18 page 124
25
THANK YOU VERY MUCH !
26
DO YOU HAVE
ANY QUESTION?
BYE NOW!
27
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