Single-stranded DNA (ssDNA) bidirectional exonuclease involved in DNA repair. Probably involved in DNA repair following ultraviolet (UV) irradiation and interstrand cross-links (ICLs) damage. Has both 5'-3' and 3'-5' exonuclease activities with a strong preference for 5'-ends. Acts as a sliding exonuclease that loads at ssDNA ends and then slides along the ssDNA prior to cutting; however the sliding and the 3'-5' exonuclease activities are abolished upon binding to the replication protein A (RPA) complex that enforces 5'-directionality activity (By similarity). Binds 1 [4Fe-4S] cluster. Monomer; monomeric form has weak exonuclease activity. Homodimer; homodimeric form is unsure but has much higher exonuclease activity, suggesting that it could homodimerize upon DNA-binding. Interacts with the replication protein A (RPA) complex (By similarity). Localizes to repair foci in response to DNA damage. Belongs to the EXO5 family.