Ratification CERD: yes in 1978, Korea has also agreed to individual petitions under article 14.

Extracts from state reply to Durban Review questionnaire:
Cases that could be specifically classified as contemporary manifestations of racism, racial discrimination, xenophobia and related intolerance are hardly found. Nevertheless, the social integration of migrant workers and women migrants is emerging as a challenge. The government has devoted efforts to improving the treatment of foreign workers and protecting their rights. Under the Employment Permit System (EPS), launched in August 2004, discrimination against foreign workers solely on grounds of racial or ethnic origin is prohibited. In May 2007 the government established the National Action Plan for the Promotion of Human Rights.

Link to the full document:
http://www2.ohchr.org/english/issues/racism/DurbanReview/session1-documentation.htm