The Jargon File (version 4.4.7, 29 Dec 2003):

kgbvax
 /K?G?B'vaks/, n.

    See kremvax.


The Free On-line Dictionary of Computing (30 December 2018):

kremvax
kgbvax

   /krem-vaks/ (Or kgbvax) Originally, a fictitious Usenet site
   at the Kremlin, named like the then large number of Usenet
   VAXen with names of the form foovax.  Kremvax was announced
   on April 1, 1984 in a posting ostensibly originated there by
   Soviet leader Konstantin Chernenko.  The posting was actually
   forged by Piet Beertema as an April Fool's joke.  Other
   fictitious sites mentioned in the hoax were moskvax and
   kgbvax.  This was probably the funniest of the many April
   Fool's forgeries perpetrated on Usenet (which has negligible
   security against them), because the notion that Usenet might
   ever penetrate the Iron Curtain seemed so totally absurd at
   the time.

   In fact, it was only six years later that the first genuine
   site in Moscow, demos.su, joined Usenet.  Some readers
   needed convincing that the postings from it weren't just
   another prank.  Vadim Antonov, senior programmer at Demos and
   the major poster from there up to mid-1991, was quite aware of
   all this, referred to it frequently in his own postings, and
   at one point twitted some credulous readers by blandly
   asserting that he *was* a hoax!

   Eventually he even arranged to have the domain's gateway site
   *named* kremvax, thus neatly turning fiction into truth and
   demonstrating that the hackish sense of humour transcends
   cultural barriers.  Mr. Antonov also contributed some
   Russian-language material for the Jargon File.

   In an even more ironic historical footnote, kremvax became an
   electronic centre of the anti-communist resistance during the
   bungled hard-line coup of August 1991.  During those three
   days the Soviet UUCP network centreed on kremvax became the
   only trustworthy news source for many places within the USSR.
   Though the sysops were concentrating on internal
   communications, cross-border postings included immediate
   transliterations of Boris Yeltsin's decrees condemning the
   coup and eyewitness reports of the demonstrations in Moscow's
   streets.  In those hours, years of speculation that
   totalitarianism would prove unable to maintain its grip on
   politically-loaded information in the age of computer
   networking were proved devastatingly accurate - and the
   original kremvax joke became a reality as Yeltsin and the new
   Russian revolutionaries of "glasnost" and "perestroika" made
   kremvax one of the timeliest means of their outreach to the
   West.

   [Jargon File]