A good description is "dirty trick".

= Underhand political or commercial activity designed to discredit an opponent.

Oxford lexico

If you insist on one word, three come to mind:

subterfuge = a trick or a dishonest way of achieving something

machinations = complicated and secret plans, esp. in obtaining or using power

ruse = a trick intended to deceive someone

[Cambridgedictionary]

Of these I prefer ruse, which is short and snappy and has a strong feeling of deception.

A good description is "dirty trick".

= Underhand political or commercial activity designed to discredit an opponent.

Oxford lexico

If you insist on one word, three come to mind:

subterfuge = a trick or a dishonest way of achieving something

machinations = complicated and secret plans, esp. in obtaining or using power

ruse = a trick intended to deceive someone

[Cambridgedictionary]

Of these I prefer ruse, which is short and snappy and has a strong feeling of deception.

The suggestions above only apply to circumstances that were contrived by the beneficiary. If advantage is taken from circumstances that were not contrived it is opportunism.