1
general::
Emerging from obscurity or a place of seclusion. It often is put as come (or crawl)out of the woodwork, as in The candidates for this job were coming out of the woodwork. The expression alludes to insects crawling out of the interior wooden fittings of a house, such as baseboards and moldings. [Colloquial; mid-1900s]
American Heritage Idioms
2
general::
Phrase(s): *out of the woodwork
Fig. out into the open from other places or a place of concealment. (*Typically: bring someone or something ~; come ~; creep ~.) • When the cake appeared, all the office people suddenly came out of the woodwork.
McGrawhill's American Idioms And Phrasal Verbs