A simple way to add a collider to a Unity LineRenderer, intended for 2D use, can be adapted to 3D aswell!

LineCollider.cs

using UnityEngine;

[RequireComponent(typeof(BoxCollider2D), typeof(LineRenderer))]
public class LineCollider : MonoBehaviour
{
    private LineRenderer lineRenderer;
    private BoxCollider2D boxCollider;

    void Awake()
    {
        lineRenderer = GetComponent<LineRenderer>();
        boxCollider = GetComponent<BoxCollider2D>();
    }

    void Update()
    {
        var dir = lineRenderer.GetPosition(0) - lineRenderer.GetPosition(1);
        var center = (lineRenderer.GetPosition(0) + lineRenderer.GetPosition(1)) / 2;
        var width = (lineRenderer.startWidth + lineRenderer.endWidth) / 2;
        var length = dir.magnitude;

        //Apply Rotation
        transform.right = dir;
        transform.eulerAngles.Set(0, 0, transform.eulerAngles.z);

        //Apply Position
        transform.position = center;

        //Scale Collider
        boxCollider.size = new Vector2(length, width) * 1 / transform.lossyScale;
    }
}