The phrase "indirect attack" means when someone or something tries to harm or defeat another person or thing in a roundabout or subtle way, rather than confronting or targeting them directly. Full definition
«In the 2016 election we saw the influence and impact of indirect attacks on the DNC and how this could shape and influence our election.» (bankinfosecurity.com)
These are called indirect attack units. (warswiki.org)
The foes in these rooms often wield firearms, something against which even Batman is almost defenseless against, and so indirect attacks from the shadows are the order of the day. (wolfsgamingblog.com)