[root@mail ~]# yum whatprovides mkpasswd
Loaded plugins: fastestmirror
Determining fastest mirrors
epel/metalink | 18 kB 00:00
* base: mirror.telepoint.bg
* epel: epel.blizoo.mk
* extras: mirror.telepoint.bg
* updates: mirror.telepoint.bg
base | 3.7 kB 00:00
epel | 4.2 kB 00:00
epel/primary_db | 6.0 MB 00:05
extras | 3.4 kB 00:00
extras/primary_db | 19 kB 00:00
updates | 3.4 kB 00:00
updates/primary_db | 2.1 MB 00:01
Warning: 3.0.x versions of yum would erroneously match against filenames.
You can use "*/mkpasswd" and/or "*bin/mkpasswd" to get that behaviour
No Matches found
[root@mail ~]# yum whatprovides */mkpasswd
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: mirror.telepoint.bg
* epel: epel.blizoo.mk
* extras: mirror.telepoint.bg
* updates: mirror.telepoint.bg
base/filelists_db | 5.9 MB 00:05
epel/filelists_db | 8.3 MB 00:07
extras/filelists_db | 11 kB 00:00
updates/filelists_db | 1.6 MB 00:01
expect-5.44.1.15-5.el6_4.x86_64 : A program-script interaction and testing utility
Repo : base
Matched from:
Filename : /usr/bin/mkpasswd

As we see expect-5.44.1.15-5.el6_4.x86_64 contains mkpasswd utility.

[root@mail ~]# yum install expect