Trojan horses simply steal personal belongings

And viruses have a wider scope

Trojan horses are actually a branch of viruses

Later, Toyin called him a Trojan horse from the beginning

So the current viruses basically only attack computer system files, etc.

Basically not used, the current anti-virus software can prevent most Trojan horse programs

Isn’t there a special Trojan horse in Jinshan?

But if you often visit some messy websites, you have to install it.,

Trojan horse killer Just a casual one

Detailed explanation

The term "virus" is often used as a generic term for any malicious code that is not, in fact, a true computer virus. This article will discuss viruses, Trojans, worms, and false alarms and how to prevent them.

What is a virus?

Computer viruses are small programs written to change the way a computer operates without the user's permission or even the user's knowledge. A virus must meet two conditions:

It must be able to execute itself. It usually places its own code in the execution path of another program.

It must be able to replicate itself. For example, it may replace other executable files with virus-infected copies of files. Viruses can infect both desktop computers and network servers.

Some viruses are designed to damage a computer by corrupting programs, deleting files, or reformatting the hard drive. Some viruses do not damage the computer, but simply replicate themselves and indicate their presence by displaying text, video, and audio messages. Even these benign viruses can cause problems for computer users. Often they occupy computer memory used by legitimate programs. As a result, it may cause abnormal operation or even cause the system to crash. Additionally, many viruses contain numerous bugs that can cause system crashes and data loss.

There are five types of viruses that can be recognized:

File infection source virus: file infection source virus infects program files. These viruses typically infect executable code, such as .com and .exe files. When an infected program is run from a floppy disk, hard drive, or network, it can infect other files. Many of these viruses are memory-resident viruses. After the memory is infected, any uninfected executable files that are run will become infected. Examples of known file-borne viruses include Jerusalem and Cascade.

Boot sector viruses: Boot sector viruses infect the system area of ??the disk, that is, the boot records of floppy disks and hard disks. The boot record of all floppy disks and hard disks (including disks containing only data) contains a small program that runs when the computer starts. A boot sector virus attaches itself to this part of the disk and activates when the user attempts to boot from an infected disk. These viruses are usually memory-resident in nature. Most of them are written for DOS, but all PCs (regardless of operating system) are potential targets for such viruses. The computer becomes infected simply by trying to boot it from an infected floppy disk. Thereafter, all non-write-protected floppy disks will be infected when they are accessed, as the virus resides in memory. Examples of boot sector viruses are Form, Disk Killer, Michelangelo, and Stoned.

Master boot record virus: Master boot record virus is a memory-resident virus that infects disks in the same way as boot sector viruses. The difference between these two virus types is the location of the virus code. Master boot record infection sources typically keep a legitimate copy of the master boot record in another location. A Windows NT computer infected with a boot sector virus or a master boot sector virus will not boot. This is due to the fact that the Windows NT operating system accesses its boot information differently than Windows 95/98. If the Windows NT system is formatted with a FAT partition, the virus can usually be eliminated by booting into a DOS system and using anti-virus software. If the boot partition is NTFS, you must use three Windows NT installation disks to restore the system.

Examples of master boot record infection vectors are NYB, AntiExe, and Unashamed.

Composite virus: Composite virus infects both boot records and program files, making it very difficult to repair. If you clear the boot sector but do not clean the files, the boot sector will become infected again. Likewise, simply cleaning the infected files will not completely eliminate the virus. If the virus in the boot area is not removed, the cleared files will be infected again. Examples of complex viruses include One_Half, Emperor, Anthrax, and Tequilla.

Macro virus: This type of virus infects data files. They are the most common, and fixing them takes up the most money and time from a company. With the advent of Visual Basic in Microsoft Office 97, macro viruses can be written to infect not only data files but other files as well. Macro viruses can infect Microsoft Office Word, Excel, PowerPoint, and Access files. Now, new threats of this type are appearing in other programs as well. All of these viruses use another program's internal programming language, which was created to enable users to automate certain tasks within that program. These viruses are easy to create, and there are thousands of them in circulation today. Examples of macro viruses include W97M.Melissa, WM.NiceDay, and W97M.Groov.

What is a Trojan horse?

Trojan horses are deceptive files (claiming to be benign but actually being malicious). The big difference between Trojans and viruses is that Trojans do not replicate themselves like viruses do. Trojans contain malicious code that can lead to data loss or even theft when triggered. For Trojans to spread, these programs must be effectively enabled on the computer, such as opening email attachments. PWSteal.Trojan is a Trojan horse.

What is a worm?

A worm is a program that copies itself between systems without using resident files. This is different from viruses, which require infected resident files to spread. Although worms typically reside inside other files (usually Word or Excel), worms and viruses use resident files differently. Typically, a worm will publish a document that already contains the "worm" macro. The entire document will be spread from computer to computer, so the entire document should be considered a worm. PrettyPark.Worm is a common example.

What is virus false reporting?

Virus false reports are messages, almost always sent via email, that are no more harmful than chain letters. Common phrases used in these false claims include:

If you receive an email titled, do not open it!

Delete now!

Contains viruses.

It will delete everything on your hard drive and .

This virus was released today by . Please forward this warning to everyone you know!

Most false virus warnings don't stray too far from this pattern. If you are unsure whether a virus warning is legitimate or false, you can obtain additional information at:

/avcenter/index.html

To submit a file or disk suspected of being infected with a virus , please review one of the following documents:

How to submit files to Symantec Security Response over the Internet or on a floppy disk

How to submit files to Symantec Security Response using Scan and Send

What is safe computer use?

With all this publicity, it's easy to think that viruses are lurking in every file, email, and website. However, the risk of infection can be minimized by taking some basic precautions. Please use computers safely and encourage everyone you know to do the same.

General Precautions

Do not leave a floppy disk in the floppy drive when shutting down or restarting the computer.

After completing writing to the floppy disk, write-protect the floppy disk.

Be wary of email attachments from unknown sources.

Confirm whether the attachment was sent by the author of the email. Newer viruses can send emails that appear to be from people you know.

Don't set your email program to "auto-run" attachments.

Get all Microsoft security updates.

Back up your data frequently. Save the (write-protected) media in a safe location, preferably away from your computer