The setuid tag has no wiki summary.
33
votes
5answers
18k views
Allow setuid on shell scripts
The setuid permission bit tells Linux to run a program with the effective user id of the owner instead of the executor:
> cat setuid-test.c
#include <stdio.h>
#include <unistd.h>
int ...
24
votes
1answer
458 views
What would be the best way to work around this glibc problem?
I administer a Gentoo Hardened box that uses file capabilities to eliminate most of the need for setuid-root binaries (e.g. /bin/ping has CAP_NET_RAW, etc).
Infact, the only binary I have left is ...
5
votes
3answers
940 views
Changing the UID of files in /proc
In a follow up to this question about changing the UID of a user, it is recommended to change the ownership of all files on the system (this answer)
find / -uid 1000 -exec chown 5000 '{}' \+
where ...
4
votes
2answers
1k views
Can gdb debug suid root programs?
I wrote a program that calls setuid(0) and execve("/bin/bash",NULL,NULL).
Then I did chown root:root a.out && chmod +s a.out
When I execute ./a.out I get a root shell. However when I do gdb ...
4
votes
2answers
133 views
Purpose of using setuid() in SUID programs
I wonder that an SUID program like passwd why using setuid function call, why he drop root privilege?
What types of attack is against(buffer-overflow)?
thanks for the answers
4
votes
1answer
186 views
root owned program with setuid bit on
Ping is a a program owned by root with the user id bit set.
$ ls -l `which ping`
-rwsr-xr-x 1 root root 35752 Nov 4 2011 /bin/ping
As I understand it, if a user runs the ping process, then the ...
4
votes
2answers
609 views
Why is mount.cifs not installed suid by default?
I am using Gentoo, and on my machine at least mount.cifs is not installed suid root by default. In particular, this means that I can't use the user mount option with CIFS shares. I noticed that ...
3
votes
1answer
135 views
Environment settings on setuid executables
I am observing a curious behavior when running a program with setuid bit enabled.
Program foo is owned by user bar with setuid bit set.
User execbar runs foo
foo reports that one of the dynamic ...
3
votes
1answer
87 views
How does having /dev/fd make running shell scripts under sudo safe?
At the end of the man page for sudo, there's the following remark:
Running shell scripts via sudo can expose the same kernel bugs that
make setuid shell scripts unsafe on some operating systems ...
3
votes
2answers
77 views
Setuid bit seems to have no effect on bash
I was experimenting with the security of my system and noticed something strange: setting the setuid bit on a copy of bash located at /usr/bin/bash-test seemed to have no effect. When I ran an ...
3
votes
1answer
130 views
Clear setuid permission using numeric mode
On an Ubuntu Linux I have a directory with the setuid bit set (drwsr-xr-x) which I want to unset.
Neither chmod 755 nor chmod 0755 nor chmod 00755 (I though maybe the first 0 is interpreted as just ...
3
votes
1answer
182 views
How to replace setuid with file-system capabilities
Inspired by this question here is the follow-up:
As some of you may know setuid-binaries are dangerous, since some exploits use these to escalate their rights up to root.
Now it seems that there has ...
3
votes
1answer
1k views
how does real and effective user ID works?
When a normal user wants to make change to the passwd file, the user will by setuid be given the effective user access. User becomes root temporarily and can edit passwd.
However you can only edit ...
3
votes
1answer
113 views
Running setuid binary temporarily without setuid?
Currently setting up xpra, which wants to run an X instance as non-root using the dummy driver, but the system Xorg binary is SUID. Since the system auto-updates, I would prefer not making and ...
2
votes
3answers
265 views
How does setting the Setuid bit affect shell scripts that run on boot of the system, before any login has occurred?
Would enabling the setuid bit on a shell script make a difference at all when that script is run on boot? Who would the effective user be?
2
votes
2answers
263 views
setuid and setgid confusion
I'm trying to fully grasp the concept of setuid and setgid, and I'm not quite sure in what way permissions are actually elevated. Let me provide an example:
Users
userA (groups: userA groupA)
userB ...
2
votes
1answer
62 views
How to set up a script to run as root non-interactively?
I need to set up the following script to run as root whenever I log in:
#!/bin/zsh
truncate -s 0 ~yourstruly/.juniper_networks/network_connect/ncsvc.log
I know how to run the script as root ...
2
votes
1answer
283 views
using Set uid to run a root command from non-root user
Consider the following two files. summarize's executable UID bit has been set, so that another user belonging to another group can execute the summarize executable that uses the customers.dat file.
...
2
votes
1answer
36 views
how to record command which execute a programme suid
My question: Is there a way to record all commands who execute a suid programme?
Like what .bash_history do, but only the setuid programmes.
2
votes
2answers
336 views
Unix executable file permission vs runtime user's permissions
I have heard that it is good practice to run an executable as a user with a completely different privilege set than the owner of the task. In fact I heard that it is best to run it as a different user ...
1
vote
3answers
1k views
What does GID mean?
What does GID actually mean?
I have Googled it and this is what linux.about.com said:
Group identification number for the process. Valid group numbers are given in /etc/group,
and in the GID field ...
1
vote
1answer
201 views
How to suid iwconfig on Debian wheezy?
I have a script running under my own user account that takes care of all sorts of wireless interfaces. It (more or less) intelligently switches wireless LAN off and on and so forth. However, it does ...
1
vote
3answers
408 views
How does the set-user-ID mechanism work in Unix?
Can someone please explain the set-user-ID mechanism in Unix ? What was the rationale behind this design decision? How is it different from effective user id mechanism ?
1
vote
2answers
127 views
setuid programs don't seem to run setuid in TinyCore Linux
I want to demonstrate the vulnerability of setuid programs using the TinyCore Linux live cd. That is, I craft a special program, with special permissions, so that it runs as the owner of the file ...
-1
votes
1answer
174 views
Are there any setuid/setguid bits in OpenBSD?
https://en.wikipedia.org/wiki/Setuid
Are there anything like this under OpenBSD?
