Security must read: Is the computer poisoned? Demystifying several misunderstandings of antivirus

The article is very long, but if you are interested in security, please read it carefully.

Have your computer been poisoned, have you been confused by the virus, I will tell you, several ways to keep you away from the virus, let you know the misunderstanding of antivirus.

DIR operation on infected floppy disk will cause the hard disk to be infected

If the computer's memory has no virus, the computer will be infected only after executing the program (file) with the virus. The DIR command is an internal command of DOS and does not need to execute any external programs (files). Therefore, DIR operations on infected floppy disks are not infected with viruses.

However, it should be noted that if there is a virus in the computer's memory (or the computer has been infected), if you do DIR operation on a floppy disk that is not infected, you may be infected with a floppy disk. Said it may be infected because some viruses will not spread through DIR operations.

Change the file to read-only mode to avoid infection.

Some people think that setting the file to read-only via DOS's external command ATTRIB is very effective against viruses. In fact, to modify the properties of a file only need to call a few DOS interrupts, so the ATTRIB command is almost impossible to stop the infection and spread of the virus.

Virus can infect write-protected disks

Because viruses can infect read-only files, many people think that viruses can also modify files on write-protected disks. In fact, the disk drive can determine whether the disk is write-protected and should be written to it. This is all controlled by hardware. You can physically remove the write-protection sensor of the pc, but you can't do it with software. .

If your floppy drive is normal, and the write protection of the floppy disk is not taken off once, it will never be infected. But if you take it down and use the poisoned machine DIR, you are completely infected. Note that this DIR is from the machine to the floppy disk, not the virus from the floppy disk to the machine.

Write protection and file read-only mode are different. The read-only mode of setting files is through the computer, so the virus can be plugged in, but the write protection must be done by humans. The virus can't get rid of write protection. The computer cannot overwrite the write-protected disk, which cannot be changed by any operation (unless you break the drive).

Anti-virus software can kill all known viruses. There are many ways to infect the virus. Some viruses will forcibly cover a certain part of the execution program and embed its own code to achieve no change. For the purpose of file length, the code covered by such a virus cannot be recovered, so the virus cannot be safely killed. The virus destroys some of the contents of the file. After killing the virus, it is impossible to restore the original appearance of the file.

Using anti-virus software can protect you from viruses.

The anti-virus software currently on the market can only be used after the virus has flooded. But before the anti-virus, the virus has caused work delays, data damage or other more serious consequences. Therefore, you should choose a complete anti-virus system, which should include not only common check and virus killing functions, but also real-time anti-virus functions. It can monitor and track various operations on files in real time. Alert immediately, the only way to minimize the chance of being infected by a virus.

Disk file corruption is mostly caused by viruses

File corruption is caused by various reasons, power supply voltage fluctuations, power loss, magnetization, poor disk quality, hardware errors, errors in other software, Dust, soot, tea, and even a sneeze can cause data loss. The damage caused by the above files is more common and more serious than the damage caused by viruses.

If you back up the disease when backing up, then these backups are useless

There are two cases: 1 floppy disk backup: the backup contains a boot virus. In this case, as long as you don't use this floppy disk to try to boot your computer, it will be as safe as a non-toxic backup. 2 tape backup: There will be no virus in the data file in the backup. If the executable file contains a virus, the execution file will be backed up, but the data file in the backup is still available.

Anti-virus software can prevent any disease anywhere, anytime

Obviously, this anti-virus software does not exist. New viruses are constantly appearing, requiring anti-virus software to be upgraded quickly. To fight the virus, we need a security policy and a complete anti-virus system, using backup as the first line of defense against anti-virus, anti-virus software as a second line of defense. At the same time, the timely upgrade of the software is the only way to strengthen the second line of defense. The use of anti-virus software is to aid in anti-virus, it can not be a guarantee of invulnerability.

Genuine software does not carry viruses, can be used safely

Computer users are often told, "In order to prevent virus damage, do not use software of unknown origin". This is a good statement. The so-called "unknown software" is indeed one of the main ways of computer virus transmission. So can you use the software with the "original" to sit back and relax? Not also! In fact, computer newspapers and periodicals have reported "genuine software" many times. "Commodity Software" carries a virus problem. The use of commodity software should not be taken lightly, and even newly purchased computers, including original computers, must be tested for viruses before use. Legal protection should be sought if there is a significant loss due to the virus in the original software.

No floppy disk, no virus, so no need to choose anti-virus software

"Without floppy disk, it will not be infected with viruses" is often heard in the primary users, it and " Using a floppy disk, it will infect a virus" is a pair of twin sisters, two different types of misinformation.

The infection of the virus is carried out by software with virus, but the floppy disk is not the only carrier with "virus software". It can be said that wherever the program (software) is available, it is possible to "get" the virus. That is to say, using a CD, hard disk, tape, or using a local wide area network, Internet, BBS (electronic bulletin board) or downloading software is potentially dangerous. In recent years, the widespread use of the Internet and BBS has made it possible to spread the spread of large-scale and high-speed viruses at home and abroad. These international computer information media are potential viral sources and conduits (of course, these network systems also have a high security anti-virus system), so that every computer user is exposed to the threat of exposure. - I am afraid no one will say that his computer will never connect to the Internet.

People can't be sick, so computers can never be infected, so you must choose anti-virus software.

"It's enough to kill the virus" and "There is an anti-virus software"

"It's enough to kill the virus" and "There is an anti-virus software". This is part of the people. The idea when choosing anti-virus software. A common situation is that when your computer is not normal, you can find a lot of anti-virus software, whether it is genuine or pirated, it can be good to check the virus. In fact, many computer failures are not caused by viruses. In this way, many anti-virus softwares are "invalid"; another more common situation is that users generally do not pay attention to the difference between "checking poison" and "anti-virus", using some anti-virus software. The "antivirus" operation is preferred. So, when it used the anti-virus software to "kill" the system once, and with other anti-virus software, it can no longer find the virus, then it is considered that the software is the best.

There is currently no anti-virus software that can kill all viruses, and no one can do it. Due to the different sources of various virus specimens, and the strength of the programmers, there is always a virus that can be detected by software, but other software cannot be killed. Or because some bugs (program errors), so that some software can be detected by the virus, in some versions of it can not kill or misunderstand the manslaughter. Therefore, it is generally not recommended for users to choose an anti-virus software.

When choosing anti-virus software, please first abandon all your prejudices about "good" and "bad", and reject all kinds of temptations on advertising words, and seriously understand the technology of virus-killing software vendors. Strength, service quality, software performance and other aspects. In particular, you should understand the credibility of software vendors' measures and commitments in terms of upgrades, returns, and damage replacement. At the same time, you should ask the manufacturers to directly explain the specific meanings of the various terms they use in advertising. You must know that this is your legitimate right as a consumer.

The current anti-virus software market is like the "Warring States era", and every family says that each family is good. But consumers feel uneasy, who is using the software? Is it better to use only one or a few? There is no "all-in-one" in the world, no matter how good a software is, not all viruses can kill, and can't cure all diseases. Software vendors have different time to obtain virus samples. Therefore, in each time period, each software manufacturer has its own focus, and only one is not insured. In addition to the "master of omnipotence", there is no longer a omnipotent thing in this world. In order to prevent "repetitive construction", experts believe that the purchase of two anti-virus software with complementary advantages can be the best way to improve the "safety factor". Don't install several anti-virus software on the same computer. Most of them are unnecessary, and there may be problems such as preempting resources, misjudging, and crashing.