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Panda Protection

Virus Encyclopedia

Welcome to the Virus Encyclopedia of Panda Security.

ExeBug.A

Threat LevelModerate threatDamageHighDistributionNot widespread
Common name:ExeBug.A
Technical name:ExeBug.A
Threat level:Low
Alias:CMOS Killer; ExeBug; Exe_Bug; Exe_Bug.Hooker; Exe_BUg.A; Hooker; Int_0B; CMOS-1; Swiss Boot¿½
Type:Virus
Effects:   It carries out damaging actions on the affected computer. It does not spread automatically using its own means.
Affected platforms:

MS-DOS

Detection updated on:March 31, 1999
StatisticsNo

Brief Description 

    

ExeBug.A is a virus that spreads to other computers by copying its code to other files or programs.

 

ExeBug.A uses the following propagation or distribution methods:

  • Exploiting vulnerabilities with the intervention of the user: exploiting vulnerabilities in file formats or applications. To exploit them successfully it needs the intervention of the user: opening files, viewing malicious web pages, reading emails, etc.
  • File infection: it infects different types of files, which are then distributed through any of the usual means: floppy disks, email messages with attachments, Internet download, files transferred via FTP, IRC channels, P2P file sharing networks, etc.

 

ExeBug.A uses the following infection strategies:

  • Resident: once it has been run, the virus goes memory resident and stops functions belonging to the operating system. Therefore, every time the operating system or an application tries to access any of these functions, the virus will activate and infect new files.

Visible Symptoms 

    

Once the infection has been carried out it will be necessary to boot the computer from a floppy disk. Even in that case, the hard disk might be inaccessible as its File Allocation Table is corrupted. The virus overwrites EXE files and prevents the system from detecting disk drives.