We consider dark soliton in a Bose-Einstein condensate in the presence of a
weak disorder potential. Deformation of the soliton shape is analyzed within
the Bogoliubov approach and by employing expansion in eigenstates of the
P\"oschl-Teller Hamiltonian. Comparison of the results with the numerical
simulations indicates that the linear response analysis reveals good agreement
even if the strength of the disorder is of the order of the chemical potential
of the system. In the second part of the paper we concentrate on quantum nature
of the dark soliton and demonstrate that the soliton may reveal Anderson
localization in the presence of a disorder. The Anderson localized soliton may
decay due to quasi-particle excitations induced by the disorder. However, we
show that the corresponding lifetime is much longer than condensate lifetime in
a typical experiment.Comment: 10 pages, 3 figures, version accepted for publication in Phys. Rev.