From the course: Red Hat Certified System Administrator (EX200) Cert Prep: 2 File Access, Storage, and Security
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Special file bits: SUID and SGID
From the course: Red Hat Certified System Administrator (EX200) Cert Prep: 2 File Access, Storage, and Security
Special file bits: SUID and SGID
- [Instructor] There are additional special bits for privilege escalation on executable files. The first is called set user ID, or SUID, which instructs Linux to run the executable file as the user owner of the file. We also have set group ID, or SGID, which instructs Linux to run the executable file as the group owner of the file. And lastly, Sticky. Historically in Unix, if you set the Sticky bit on a program, it would remain in swap, making it execute faster the next time it is run. Some versions of Unix and BSD still maintain this functionality. But it has never existed in Linux. Linux caches all executables for faster execution anyway. So there's little need for a Sticky bit. In a terminal, let's do a long list on the su command by typing in ls, space, dash l, space, /usr/bin/su and hit enter. The first thing you should notice is that the file is bright red. This tells you something special is happening here. Let's take a look at the permissions. The permissions for the user…
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Contents
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File and directory modes1m 19s
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(Locked)
Change file and directory ownership3m 14s
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(Locked)
Set permissions using numeric mode3m 2s
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(Locked)
Set permissions using symbolic mode4m 46s
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(Locked)
Initial permissions using umask4m 30s
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(Locked)
Special file bits: SUID and SGID4m 59s
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(Locked)
Special directory bits: SGID and Sticky5m 55s
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(Locked)
Read access control lists3m 36s
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(Locked)
Set access control lists (ACLs)5m 49s
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(Locked)
Configure inheritance with default access control lists4m 27s
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(Locked)
Delete access control lists4m 15s
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(Locked)
Challenge: File access control2m 34s
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(Locked)
Solution: File access control6m 54s
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