Hard to tell for sure from the photo. This could be Euonymus scale.  The brown could be female scale about 1/16 inch long which are primarily found on stems.  Also noted on the photo were some tiny white spots that could be male scale. Scale can cause leaf drop if the infestation is extensive. Eggs hatch and orange crawlers appear in spring time.  You may want to prune out these areas of the branches.   Here is some information about Euonymus scale - https://pnwhandbooks.org/insect/hort/landscape/hosts-pests-landscape-plants/euonymus-euonymus-euonymus-scale