In Linux, the three most common commands that hackers usually attempt to Trojan are:

A.
car,xterm,grep

B.
netstat,ps,top

C.
vmware,sed,less

D.
xterm,ps,nc

Explanation:
The easiest programs to trojan and the smartest ones to trojan are ones commonly run by
administrators and users,in this case netstat,ps,and top,for a complete list of commonly trojaned
and rootkited software please reference this URL: http://www.usenix.org/publications/login/1999-9/features/rootkits.html