Virus-Lecture - Viruses can infect your computer by...

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Viruses can infect your computer by reading, or even, previewing, email. There are many ways that you can find out what these email You can get a virus as easily as reading an email. A site called the “EMAIL Help Center” can guide you on how to prevent this from You can test whether your email system is vulnerable to email viruses and attacks such as emails containing mail attachments, web page HTML’s, and many more types of computer processing that be infected A computer virus is a self-replicating program containing code that explicitly copies itself and that can "infect" other programs by modifying them or their environment such that a call to an infected program
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An ARMORED virus is one that uses special tricks to make tracing,disassembling and understanding of its code more difficult. EX.A good example is the Whale virus. ARMORED Virus
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A CAVITY VIRUS is one which overwrites a part of the host file that is filled with a constant (usually nulls), without increasing the length of the file, but preserving its functionality. The Lehigh virus was an early example of a cavity virus. CAVITY Virus
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The COMPANION virus is one that, instead of modifying an existing file,creates a new program which is executed instead of the intended program. On exit, the new program executes the original program so that things appear normal. On PCs this has usually been accomplished by creating an infected .COM file with the same name as an existing .EXE file. Integrity checking anti virus software that only looks for modifications in existing files will fail to detect such viruses. COMPANION VIRUS
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The first class of the common PC virus consists of the FILE INFECTORS which attach themselves to ordinary program files. These usually infect arbitrary COM and/or EXE programs,though some can infect any program for which execution or interpretation is requested, such as SYS, OVL, OBJ, PRG, MNU and BAT files. File infectors can be either DIRECT-ACTION or RESIDENT. A direct-action virus selects one or more programs to infect each time a program infected by it is executed. A resident virus installs itself somewhere in memory (RAM) the first time an infected program is executed, and thereafter infects other programs when they are executed, or when other conditions are fulfilled. Direct-action viruses are also sometimes referred to as NON- RESIDENT.The Vienna virus is an example of a direct-action virus. Most viruses are resident. FILE Infectors…for PC’s
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A POLYMORPHIC virus is one that produces varied but operational copies of itself. This is so that virus scanners will not be able to detect all instances of the virus.
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Virus-Lecture - Viruses can infect your computer by...

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