Can you attach an aura to a creature with shroud using an effect that doesn't target?

Shroud (CR 702.18a) states that the permanent or player with shroud "can't be the target of spells or abilities." The key word is target. If an effect attaches an Aura without using the word 'target' — for example, an effect that says 'attach an Aura you control to a creature' without specifying it targets — shroud provides no protection whatsoever.

When an Aura is cast normally as a spell, it targets as part of its resolution (CR 303.4), so shroud would stop that. But some cards and abilities move or attach Auras through non-targeting effects. These bypass shroud because shroud only interferes with the targeting process (CR 114.4), not with general effects that happen to affect the permanent.

Hexproof works the same way — and neither shroud nor hexproof prevents non-targeted attachments. This distinction is important: shroud is a narrow protection against the specific game action of targeting, not a blanket immunity to being affected by spells and abilities.

Concrete example: The card Enchantress's Presence is already on the battlefield. If a player activates an ability that says "attach target Aura you control to target creature," a creature with shroud is protected. But if instead an effect says "attach an Aura you control to a creature of your choice" without the word target, you can legally attach it to the shrouded creature because no targeting is involved.

See CR 702.18a for shroud and CR 114.4 for the definition of what it means to target. Always look for the word 'target' in the spell or ability text to determine if shroud applies.