The most common and most likely answer to this crossword clue is the 4 letter word BOGY
I've seen this crossword clue in The Times
B
O
G
Y
More clues leading to the result BOGY
Buddy explains!

The straight part
We know that "a malign influence" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a malign influence = bogy.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does BOGY mean?
BOGY noun- One who robs others in a lawless area, especially as part of a group.
- An outlaw.
- One who cheats others.
- An enemy aircraft.
- A runner who covertly joins a race without having registered as a participant.
- An obnoxious, selfish and overbearing person; an attention hog.
- (often capitalized, usually with definite article) The Devil.
- A ghost, goblin, or other hostile supernatural creature.
- A bugbear: any terrifying thing.
- A standard of performance set up as a mark to be aimed at in competition.
- An unidentified aircraft, especially as observed as a spot on a radar screen and suspected to be hostile.
- A score of one over par on a hole.
- A bog-standard (representative) specimen taken from the center of production.
- A swim or bathe; a bath.
- One of two sets of wheels under a locomotive or railcar; the structure with axles and wheels under a locomotive, railcar, or semi.
- (Indian English, dated in UK) A railway carriage.
- A toy similar to a violin bow, consisting of a wooden stick with notches along one or more sides or edges to produce a rattly noise when stroked against a hard edge, eg, the lip of container.
- A piece of solid or semisolid mucus in or removed from a nostril.
- Something suggestive of this material.
- A thing; especially a problematic or difficult thing.
- (mildly derogatory) A bodyboarder.