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Can the top command in /usr/bin be replaced? I read on superuser that it can hide processes if compromised. I want to delete top and get a fresh new script using apt-get from Ubuntu official repositories.

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  • 1
    Refresh it do what?
    – muru
    May 19 '17 at 9:03
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top is a part of procps package you can reinstall it using:

sudo apt install --reinstall procps

or install a version from a repository which you trust, run apt-cache policy proccps, which outputs:

procps:
  Installed: 2:3.3.10-4ubuntu2.3
  Candidate: 2:3.3.10-4ubuntu2.3
  Version table:
 *** 2:3.3.10-4ubuntu2.3 500
        500 http://mirrors.kernel.org/ubuntu xenial-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     2:3.3.10-4ubuntu2 500
        500 http://mirrors.kernel.org/ubuntu xenial/main amd64 Packages

pick a version from a repository which you trust and specifically install that one:

sudo apt remove procps
sudo apt install procps=2:3.3.10-4ubuntu2.3

You can also check and see if this file is compromise using dpkg -V:

run:

dpkg -V procps

If top has been compromised it will show you an output look like:

??5??????   /usr/bin/top

otherwise it show nothing.

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  • Shouldn't we take care of probably enabled PPA's, as untrusted PPA's are a common way to compromise the system?
    – mook765
    May 19 '17 at 10:06
  • I updated my answer, however I strongly recommend not using PPA's or sources we don't trust in first place. IMO Once they cause the damage it's hard to discover and fix.
    – Ravexina
    May 19 '17 at 10:23
  • Looks perfect, a pity we can't upvote twice...
    – mook765
    May 19 '17 at 20:37
  • Thank you, I got a downvote but I couldn't find the answer (procps). Try searching for top ...
    – imonaboat
    Jun 5 '17 at 10:06

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