Attack article penned by surrogate NCO (8)
I believe the answer is:
paroxysm
'attack' is the definition.
(paroxysm is a kind of attack)
'article penned by surrogate nco' is the wordplay.
'article' becomes 'a' (indefinite article).
'penned by' means one lot of letters goes inside another.
'surrogate' becomes 'proxy'.
'nco' becomes 'sm' (abbreviation for sergeant major, a type of NCO).
'a' put inside 'proxy' is 'paroxy'.
'paroxy'+'sm'='PAROXYSM'
(Other definitions for paroxysm that I've seen before include "Fit - convulsion" , "Uncontrollable fit (of giggles, coughing etc)" , "Seizure" , "Sudden uncontrollable outburst - fit" , "Fit of giggling" .)