I get this when trying to run this command: desktop:~$ grep nobody /etc/passwd
nobody:x:65534:65534:nobody:/nonexistent:/bin/sh
this "nobody" just popped up one day under my normal profile name and i cannot set it to /dev/null. I get permission denied.

You are seeing this error because you don't have permission to edit the /etc/passwd file. Try changing to the root account or invoke an editor using sudo.

BUT ... the nobody account is useful. It is a standard account used to perform tasks that don't require any privileges or normal user account status. The updatedb utility is usually run in a cron job under the nobody account. That way it does not update the locate database with user files unless the "others" group can see those files.

I've seen apache run as nobody as well, along with many other services so they're not run as root.

Why would you want to set user 'nobody' to /dev/null anyway? What's the purpose for that?

Linux Archive

1. echo "/dev/null" >> /etc/shells
2. as user root type; chsh /dev/null nobody

See man chsh for explanation.

i was told that With a shell of /dev/null, an attacker could not be certain whether the attempted user exists on the system -- not the case where /bin/false or /bin/nologin is the shell.

so i enter; su
then root passwd;
then; chsh /dev/null nobody
i get; Usage: chsh [options] [LOGIN]

Options:
-h, --help display this help message and exit
-s, --shell SHELL new login shell for the user account

to set nobody now to /dev/null do need to just enter; chsh /dev/null nobody -s?

also, are there any potential problems in doing so? sorry but i am VERY new to this.

In light of these option-hints I think the command would have to be:
chsh -s /dev/null nobody
or
chsh --shell/dev/null nobody

that did it! you guys are awesome. Since I have used MS systems for so long and support them professionally I am very unfamiliar with Linux in every aspect ( although i do have to say even being as new to it as i am, i am WAY happier to use it than any MS product i have ever seen). I am a pretty big security guy so if anyone could point me to some references on tools to be used in securing my Linux box i would appreciate it. Also, guarddog vs. firestarter, any opinions?

EDIT

found your link you read here

Successful su for nobody by root? post 8

http://www.linuxquestions.org/questi...05#post2555505

cheerio