Is doing others software job and getting money in exchange haram or wrong?

Assalamualaikum, I am a software engineer and I already have a job which is primary source of income. Apart from this, I give support(do his core work) to another person working at a different company usually after my work hours and get money in exchange. However, I know that this person has got the job by cheating in interview. Is my work for this person Haram or wrong as I know that he got a job by wrong means?