Most frequent symptoms of infection
- Slow down your computer: The computer is working much more slowly than usual. Takes a long time to open applications or programs. The operating system takes a long time to perform simple tasks that usually do not require much time;
- Inability to run a program or open a specific file;
- Disappearance of files and folders: files stored in specific folders (usually those belonging to the operating system or certain applications) have disappeared since deleted from the virus. Could be lost entire folders and directories;
- Inability to access the contents of files: opening a file, you receive an error message or simply can not be opened. A virus may have changed the File Allocation Table (FAT) that causes the loss of addresses that are the starting point for locating files;
- Error messages unexpected or unusual: Displaying dialog boxes contain messages absurd, funny, mischievous or aggressive;
- Reduction of space in the memory and hard drive, significantly reducing the free space on your hard disk, when a program is running, you receive a message indicating insufficient memory to do so (although this is not true and there are no other programs open)
- Bad sectors you are alerted of the existence of errors in the disk on which you are working and warned that the file can not be saved or that you can not perform an action,
- Changes in ownership of the file: The virus modifies some or all of the files it infects. Consequently are no longer correct or change the properties associated with the infected file. Among the properties most affected: time / date (of creation or last modified), size, etc;
- Operating system error: operations normally performed and supported by the operating system determines the error messages, the execution of operational requirements or the failure to execute the transaction request;
- Duplication of files: if there are two files with the same name but with extension EXE, COM, respectively, the COM extension will be a virus. Viruses do so because if there are two files with the same name as the operating system will always first with the COM extension;
- Renaming of files: a virus can rename files infected and / or specific files;
- Problems starting the computer: The computer does not start or not start in the usual way;
- Computer crash: despite the opening of a few or no programs and the lack of a heavy load on the system, it hangs ( ‘Crash’), making it necessary to use the Task Manager to remove the blocked task or reboot the computer ;
- Stopping the running program without the user has performed operations unexpected or done something that could have caused this result;
- Opening and closing the CD / DVD without user intervention;
- Keyboard and / or mouse not working properly: the keyboard does not write what is typed by the user or transactions which do not correspond to your key presses. The mouse pointer moves by itself or independently from the movement requested by the user;
- Disappearance of sections of windows specific sections (buttons, menus, texts etc.) that should appear in a particular window are missing or not displayed. Or in windows in which should not appear anything but icons appear strange or unusual content (e.g., in the Windows taskbar).
Spontaneous Reboot the computer
- Antivirus turned off automatically;
- Programs suddenly no longer functional or dysfunctional;
- Slowness of Internet connection;
- Issuance by the computer sound unusual;
- Microsoft Internet Explorer crashes or otherwise malfunctioning, ensuring the continuity errors (for example, fails to close the applications)
Keep in mind that the symptoms described above may be due to causes other than viruses. In the case of presence of one or more of these symptoms, it is advisable to run a virus scan of system;
Techniques Used For Detection Of Virus
There is a general method to identify viruses within a system. The detection techniques used by the virus are different: used simultaneously guarantee an excellent probability of detection of the presence of a virus. According to detection techniques used, the virus can be divided into three types:
- Monitoring programs: are aimed at preventing infection by monitoring for suspicious activity (for example, the request to format a disk or access to privileged areas of memory). They are important because they represent the first line of defense. But they are easy to pass through the technique of tunneling.
- Scanner searches for viruses through two techniques:
- a) For the comparison of signatures stored in an internal database with those possibly contained in files infected;
- b) For use of heuristics to viruses that are encrypted or unknown.
Programs detection: using two techniques:
- Check the integrity: calculate the hash of files to be compared later with the new values resulting from a new calculation to verify that files have not changed in the meantime.
- Heuristics: save enough information to restore the original file if it is damaged by a virus.
Study: From Wikipedia, the free encyclopedia. The text is available under the Creative Commons.
Link to this post!
Related posts: