LinuxQuestions.org
Share your knowledge at the LQ Wiki.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Security
User Name
Password
Linux - Security This forum is for all security related questions.
Questions, tips, system compromises, firewalls, etc. are all included here.

Notices


Reply
  Search this Thread
Old 07-01-2000, 12:05 PM   #1
jeremy
root
 
Registered: Jun 2000
Distribution: Debian, Red Hat, Slackware, Fedora, Ubuntu
Posts: 13,028

Rep: Reputation: 3756Reputation: 3756Reputation: 3756Reputation: 3756Reputation: 3756Reputation: 3756Reputation: 3756Reputation: 3756Reputation: 3756Reputation: 3756Reputation: 3756

This is getting pretty old, but it is serious enough that I'll post it.

There is a problem in the following kernels that will allow a local user to gain root. If you have a system that has local users it is HIGHLY recommended that you upgrade to 2.2.16 (or the LATEST 2.4 series if you are so inclined).
Vulnerable:
Linux kernel 2.4.0-test1
Linux kernel 2.2.15pre20
Linux kernel 2.2.15pre16
Linux kernel 2.2.15
Linux kernel 2.2.13
Linux kernel 2.2.12

Details:
POSIX "Capabilities" have recently been implemented in the Linux kernel. These "Capabilities" are an additional form of privilege control to enable more specific control over what priviliged processes can do. Capabilities are implemented as three (fairly large) bitfields, which each bit representing a specific action a privileged process can perform. By setting specific bits, the actions of priviliged processes can be controlled -- access can be granted for various functions only to the specific parts of a program that require them. It is a security measure. The problem is that capabilities are copied with fork() execs, meaning that if capabilities are modified by a parent process, they can be carried over. The way that this can be exploited is by setting all of the capabilities to zero (meaning, all of the bits are off) in each of the three bitfields and then executing a setuid program that attempts to drop priviliges before executing code that could be dangerous if run as root, such as what sendmail does. When sendmail attempts to drop priviliges using setuid(getuid()), it fails not having the capabilities required to do so in its bitfields. It continues executing with superuser priviliges, and can run a users .forward file as root leading to a complete compromise. Procmail can also be exploited in this manner.

 
Old 03-11-2005, 06:32 PM   #2
puffinman
Member
 
Registered: Jan 2005
Location: Atlanta, GA
Distribution: Gentoo, Slackware
Posts: 217

Rep: Reputation: 30
Yeah, this IS old.

(Doing my part to clear out the no-replies! )

Last edited by puffinman; 03-11-2005 at 06:33 PM.
 
Old 03-15-2005, 03:03 AM   #3
penguinlnx
Member
 
Registered: Mar 2005
Location: Ice Station Alert AFB
Distribution: Gentoo
Posts: 166

Rep: Reputation: 30
Internet access for other local users

How do you go about setting up permissions for local users to use the internet?
Is it an automatic or default priviledge?
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off



Similar Threads
Thread Thread Starter Forum Replies Last Post
phpBB Vulnerability Capt_Caveman Linux - Security 6 10-08-2005 01:22 PM
IM vulnerability for Message services in Linux(?) penguinlnx Linux - Security 98 03-26-2005 01:48 PM
Remote Kernel Vulnerability affects 2.6.9 TruckStuff Linux - Security 1 12-16-2004 10:21 AM
Linux vs Mac question (Virus vulnerability related) unixfreak Linux - Security 14 08-29-2004 07:05 AM
UPnP vulnerability in XP anoop_chandran General 13 01-08-2002 01:01 AM

LinuxQuestions.org > Forums > Linux Forums > Linux - Security

All times are GMT -5. The time now is 10:01 PM.

Main Menu
Advertisement
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration