Section: Threats and Vulnerabilities
Explanation/Reference:
Explanation:
A backdoor in a computer system (or cryptosystem or algorithm) is a method of bypassing normal
authentication, securing unauthorized remote access to a computer, obtaining access to plaintext, and so
on, while attempting to remain undetected. The backdoor may take the form of an installed program (e.g.,
Back Orifice) or may subvert the system through a rootkit.
A backdoor in a login system might take the form of a hard coded user and password combination which
gives access to the system.
Although the number of backdoors in systems using proprietary software (software whose source code is
not publicly available) is not widely credited, they are nevertheless frequently exposed. Programmers have
even succeeded in secretly installing large amounts of benign code as Easter eggs in programs, although
such cases may involve official forbearance, if not actual permission.
Many computer worms, such as Sobig and Mydoom, install a backdoor on the affected computer
(generally a PC on broadband running Microsoft Windows and Microsoft Outlook). Such backdoors appear
to be installed so that spammers can send junk e-mail from the infected machines. Others, such as the
Sony/BMG rootkit distributed silently on millions of music CDs through late 2005, are intended as DRM
measures-and, in that case, as data gathering agents, since both surreptitious programs they installed
routinely contacted central servers.