All perfect praise be to Allah, The Lord of the Worlds, and may His peace and blessings be upon our Prophet Muhammad and upon all of his family and companions.
Good intercession means a qualified person exercising his right in having a job while being efficient for, as deemed by the specialists of that field.
Evil intercession is when a person gets a job although he isn't efficient for it and usurps others' rights due to having connections.
Allah, The most Exalted, Said in this regard (What means): "Whoever intercedes with a good intercession shall receive a share of it; and whoever intercedes with an evil intercession, shall receive the like from it. God conserves all things. " [An-Nisa' /85].
Moreover, an evil intercession lies only in common interests among people, such as public jobs which are everybody`s right. However, private interests that belong to the private sector, such as private companies, have the right to appoint whoever they desire since this matter has nothing to do with competition. And Allah Knows Best.