We present a search for low-mass (≤ 20 GeV=c2) weakly interacting massive particles (WIMPs), strong
candidates of dark matter particles, using the low-background CsI(Tl) detector array of the Korea Invisible
Mass Search experiment. With a total data exposure of 24,524.3 kg days, we search for WIMP interaction
signals produced by nuclei recoiling from WIMP-nuclear elastic scattering with visible energies between
2 and 4 keVee (electron-equivalent energy). The observed energy distribution of candidate events is
consistent with null signals, and upper limits of the WIMP-proton spin-independent interaction are set with
a 90% confidence level. The observed limit covers most of the low-mass region of parameter space favored
by the DAMA annual modulation signal assuming the standard halo model.