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Those are not System World Writables in LINUX/UNIX

 
DharmaRao G
Advisor

Those are not System World Writables in LINUX/UNIX

Please guide and suggest those are not system World Writables files in LINUX/UNIX.
2 REPLIES
Sajjad Sahir
Honored Contributor

Re: Those are not System World Writables in LINUX/UNIX


Dear Dharma Rao

Files, directories and devices that can be modified by any user are known as "worldâ writable" and are dangerous security holes. Ratcheting down your permissions also protects legitimate users from mistakes.

Unix describes file permissions using a 10-character reference. The first indicates the type of file; the next nine characters taken in groups of three show who on your computer can read, write and execute the file. Three classes of permissions show who can modify it -- owner, group and other. For example, -rwxr-x--- is a plain file whose owner has read, write and execute privileges, those in the group can read and execute it, and no access is granted to anyone else.

Vulnerable files that should not be worldâ writable include: .login; .rhosts; dev/drum; /dev/mem; /dev/kmem (nor world-readable either); /etc/passwd and /etc/group (owner root and mode 644 recommended); and device files for hard disk partitions.

If you have a server that exports file systems containing system programs like in the /bin and /usr/bin directory, you might export them Read Only, thus rendering the client unable to modify files in that directory. To export a file system Read Only, you must specify the Read Only option in the /etc/export or /etc/dfs/dfstab file on the server.

In general, files beginning with a period should not be world- or group-writable. Home directories and their associated files should be writable only by the owner. Many files should only be readable by the owner as well, hindering an intruder searching for other attack avenues. Using the 4-digit octal representation of permissions, this would be 0600.

thanks and regards

Sajjad Sahir

Re: Those are not System World Writables in LINUX/UNIX

Instead of creating 4 threads about the same topic, please continue replying to your previous threads:
http://forums.itrc.hp.com/service/forums/questionanswer.do?threadId=1340325
http://forums.itrc.hp.com/service/forums/questionanswer.do?threadId=1338013