The phrase "of dubious background" is correct and usable in written English.
It is usually used to describe something or someone whose background or past is questionable or uncertain. For example: "The new employee had a dubious background, so I was not sure if I could trust him."
He is a man of dubious background and dubious ideas.
Hundreds were fired in 1979, in a Carter administration shake-up, and in the Clinton administration, barriers to the recruitment of criminals and others of dubious background were set up.
A car is reported stolen and turns up with a diamond dealer's corpse inside, and Maigret begins his investigation with the obvious suspect, an immigrant of dubious background whose ramshackle house is a nest of questionable habits and suspicious intentions.
Brian Murphy, at Talking Points Memo, has some of the dubious background of the project.
His choice of senior figures -- and the regularity with which they are then shed -- does not augur well for either the expertise or the stability of any incoming Trump Administration; especially given the dubious background of several key advisors.
Despite this dubious background, Abrams' career in Washington remained has remained intact.
The ties that Manafort had with Firtash – which included three meetings in 2008, according to documents that were part of the lawsuit – in their abortive real estate ventures involved a maze of companies and solicitations of investors with dubious backgrounds.
Asked why security men with dubious backgrounds worked at the fateful Colosio rally, the PRI's municipal president said the Grupo Tucan was composed of veterans of such events and that accusations are spreading out of control.
He is moving to this new enterprise from a background in high frequency trading, a field that is in my mind of dubious social utilty.
Both were establishments of dubious repute.
The corporate strategy is of dubious value.
