Ubuntu Security :: Why Few Firewalls To Prevent System
Jul 14, 2011Windows have many firewalls to prevent the system. But Ubuntu have few. Why is it so? Is it not needed to prevent Ubuntu or if it is prevented?
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Security :: Safe To Use IPTables Firewalls?
Jun 14, 2010Other than Firestarter, how safe is it to use an iptables firewall for Linux if you know the basics of iptables but not the details and not exactly what you're doing with iptables? I want to be very secure without configuring iptables myself if possible or doing as little as possible. If you don't think iptables is safe if you don't really know what you're doing, which firewall you can use (Slackware specific, preferably) that is the easiest to install and configure? Are there any that work like free Windows firewalls, other than Firestarter? I've looked around and looked at slackbuild and can't find a Firestarter package, I searched this site also and saw something about the reason there isn't one. I'm concerned with my security and I don't want to write my own iptables firewall - I don't fully know what I'm doing.
View 6 Replies View RelatedUbuntu Security :: Prevent Fork Bombs From Bringing The System To Grinding Halt?
Mar 18, 2011So I am basically just curious about this, but is there a way to prevent fork bombs from bringing the system to grinding halt in Ubuntu, without setting hard limits on the resources available to users? I read about fork bombs on Wikipedia, and being the masochist I am (and not having any unsaved work), I tried entering those 13 characters into terminal. Wow. I have never seen a computer freeze up so fast.What really peaked my curiosity is that the same fork bomb has almost no effect on the performance of Mac OSX (10.6). I know that one can limit the availability of resources to specific users. Is that essentially what Snow Leopard is doing?
View 9 Replies View RelatedSecurity :: Prevent A Non-root User From Shutting Down, Rebooting Or Suspend The System?
Mar 3, 2010I'm using Gnome and I'd like to still have the ability to reboot/shutdown from one particular account as well as root. How would I modify the chmod command to add this ability?Also, I have a few users who just will hold the power button in to shutdown the machine. How can I keep them from doing this?// Pruned from the vintage 2007 Prevent a non-root user from shutting down, rebooting or suspend the system thread. Please create new threads instead of resurrecting ancient ones.
View 2 Replies View RelatedSecurity :: IPTABLES Vs Other Firewalls / All Network Connections That Come In To Services That Do Not Use TCP Wrappers?
Jul 23, 2010I'm having problems with hackers from across the globe trying to get into our servers. Why? i have no clue. nothing of value in my servers worth getting.
Right now my service only does business with USA. So I'm trying to find a way to block all Non USA traffic. I called my hosting provider and they are unable to help. Said it was up to me to do this.
Well I've already taken care of the TCP Wrappers. by spawning a small C program i made that uses MaxMind's GeoIP system. to automatically deny access. Now i need to do something about all the other network connections that come in to services that do not use the TCP wrappers.
So i was wondering if IPTABLES have a way to spawn a sub proccess like TCP wrappers or if there was any other firewall software out there for linux that would let me achieve my goal.
Ubuntu Security :: MoBlock Does Not Prevent Browsing To Blocked IPs?
Mar 11, 2010I have installed MoBlock as instructed here: [URL]
After installation I created my own list file in /etc/blockcontrol/custom-blocklist.p2p and have the following uncommented at the bottom of /etc/blockcontrol/blocklists.list:
Code:
locallist /etc/blockcontrol/custom-blocklist.p2p
The list contains the following 2 entries:
Code:
Yahoo:98.137.149.56
Google:74.125.47.147
When I do:
[Code].....
Recently I just noticed that the locallist rules seem to have no effect. I will always get "destination port unreachable" even if the locallist entry in blocklists.list is commented out.
However, whenever I try to browse to that IP, even when blockcontrol is on, even by typing the IP into Konqueror (not the domain name), it lets me go there every time. How can I know that my other applications will not to do the same thing? How can I lock this down and test it empirically to be sure?
Ubuntu Security :: Prevent Kernel Initramfs Extraction?
Jul 16, 2010I'm writing here because it's mainly a security issue even though it's rather kernel related.
I'm compiling my own vanilla kernel with an initramfs included in the bzImage. That image contains encryption keys for the rest of the system. Even though it's not for everybody the initramfs image can be extracted from the kernel, decompressed and the keys extracted.
I'm looking on a way to prevent this.
Ubuntu Security :: Prevent / Disable Copy Of A File?
Feb 5, 2011How do I prevent/disable a file from being copied?
I would want someone to be able to see the content of a directory, then open the relevant document, but just for viewing purpose. They cannot copy the file, either through copy + paste or File/Save As.
Is that possible under Ubuntu?
Ubuntu Security :: Prevent Users From Changing Settings
Jun 15, 2011I am administrating a system with about 40 or 50 users, and we recently jumped ship from windows to ubuntu. Most of my users are getting along fine, but it seems every few days, i have to help someone who accidentally changed something, and now their account (or more rarely, the machine) is unusable, and has to be reset.
I know configuring /etc/sudoers is a huge step toward fixing my problem, but that still will not completely solve it. What I would like to do is prevent users from making ANY changes to the system (aside from their work files and the like), including themes, icons, desktop, background, etc.
Security :: How To Prevent Duplicate UIDs
Oct 8, 2010I have been learning Linux for the past few months and just recently started with Bash programming. Using scripts it is possible to find users with duplicate UIDs but is there any way or script why which duplicate UIDs can be prevented altogether.
View 7 Replies View RelatedUbuntu Security :: Firewall: Completely Prevent Any Traffic From Network?
Jan 4, 2010I have Ubuntu 8.04 as virtual host. On this host I have installed VirtualBox virtualization software. I have installed Windows XP as virtual machine and installed HTTP server.I would like temporally disable all network connections to host and virtual machine.So on Ubuntu host I have set firewall settings:
Code:
sudo iptables -F (to flush - delete all firewall settings)
sudo iptables -P INPUT DROP (to disable all input traffic)
[code]....
Ubuntu Security :: How To Prevent Grub Command-line Boots
May 18, 2011The ability to manually boot using the Grub command-line constitutes a big security risk in Linux, IMO.Any OS can be booted in this manner from a PXE-LAN, USB, or CD/DVD drive, circumventing BIOS-imposed boot restrictions. (Once a foreign OS is booted, of course, it can be used to access any part of an unencrypted hard drive.) Placing passwords or locking menu items (in the Grub configuration files) does not prevent a user from booting manually using commands entered at the grub command-line.
As it stands now, when presented with the Grub menu (or after bringing up a hidden Grub menu with the "ESC" key), a user only needs to hit "c" to enter the Grub command-line mode to facilitate any type of bootup whatsoever. (They can then enter manually the Grub commands to boot an OS on any device.) This is extremely insecure and allows any passerby to boot the computer with a few keystrokes and a bootable USB drive. How do I configure Grub so that it will require a password in order to enter the command-line mode (and thereby restrict boot options to the menu, which can then be password protected/locked) ?
Fedora Security :: Prevent Firefox With SELinux?
May 11, 2009I am new to Fedora 10, and to SELinux too.
I would like to know how can I prevent from users with role user_r to connect to Internet with firefox.
Security :: Prevent Ddos Apache Attacks?
Jan 25, 2011recently my Apache server crashes very often; by watching the error log,I've notice several signs of intrusion.So, I think the problem can be a denial of service attack against my machine.My distribution is Debian Lenny.
View 2 Replies View RelatedSecurity :: Prevent Same User Ssh To The Multiple Server
May 23, 2010how to prevent same user from ssh to multiple linux server at a same time , anyone of you have the script or how to do that ?
View 16 Replies View RelatedSecurity :: Prevent Spying Keyboard Input?
Oct 16, 2009I just made a script to read out /dev/input/event3 into a file (My keyboard is identified here [ Machine is a laptop which runs on slax-atma distro ]). Then used a hexdump to convert the binary into hex. After that used a gwak script to print out the keys corresponding to each keyboard input. So now when I put this in my rc.local , It is taking down all the keys I press. Including login passwords (In short, each and every keys I press).Isn't this a big security risk, because intruder who has a physical access to my machine or has root password can put this file in rc.local and run a script to mail him all the details like my passwords, account and PIN numbers.
View 14 Replies View RelatedSecurity :: How To Prevent The Execution Of Malicious Commands
Oct 16, 2010how to prevent the execution of the following commands or how to set a policy or rule that prevents the execution of the following malicious commands
dd if=/dev/zero of=/dev/sda
rm -rf /
Security :: Prevent Users From Changing Their Password?
Jul 17, 2010I use the following method for preventing the users from changing their passwords , is there any other method other than this ?ls -l /usr/bin/passwd-rwsr-xr-x 1 root root 37140 2010-01-26 12:09 /usr/bin/passwdso we need to remove the suid for that command as follows :- chmod u-s /usr/bin/passwdnow normal users won't be able to change their own passwords - and only the root user will be able to do it for them.
View 9 Replies View RelatedUbuntu Security :: Protecting My Privacy - Measures To Prevent My ISP From Keeping Data
Jun 12, 2010Intrepid Ibex (U8.10) is what I am using presently and I would like to know if there are measures that I can take to prevent my ISP from keeping data that flows between my PC and it.
I am living in Australia, I am wanting to keep the bastards (read: Australian Government) ignorant about what I use my PC for.
Its them storing any of my personal information that I am worried about, but if I can keep my history from them completely, even better...
Ubuntu Security :: Prevent Desktop Users From Viewing The Wireless Password?
Dec 3, 2010The title says it; I want to prevent users from viewing the wireless network password.
View 9 Replies View RelatedUbuntu Security :: One Limit The Number Of Open Sockets To Prevent Exploiting?
Dec 6, 2010I was searching around and I stumbled upon a Linux Kernelix Sockets Local Denial of Service exploit.I downloaded the exploit, compiled it ran it to check if I am vulnerable.As I was expecting, the exploit instantly "killed" my Maverick system and I had to use the power button to reset my computer...Is there any way to limit the numberof allowed open sockets?I don't think that this can be done using /etc/security/limits.conf in a similar way of preventing the fork bombs
View 1 Replies View RelatedFedora Security :: Prevent People From Unauthorized Access?
Mar 19, 2009I'm doing a research to protect my pc from physical access. What I'm facing here is that my company created a program for fedora 8 and plans to sell the unit away. We created a function where you can configure the program using any web browser from a network so we do not want anybody to have access to the fedora except for out personnel.
Based on my research, I've found [URL] this guide to protect people from accessing grub and single user. I am currently researching on preventing others to clone the harddisk. I would like to know if there are any other methods to prevent people from unauthorized access to fedora.
Security :: How Does Mktemp Prevent Denial Of Service Attack
Apr 22, 2010This is an excerpt from the Linux man page for mktemp command: "mktemp is provided to allow shell scripts to safely use temporary files. Traditionally, many shell scripts take the name of the program with the PID as a suffix and use that as a temporary filename. This kind of naming scheme is predictable and the race condition. It creates is easy for an attacker to win. A safer, though still inferior approach is to make a temporary directory using the same naming scheme. While this does allow one to guarantee that a temporary file will not be subverted, it still allows a simple denial of service attack. For these reasons it is suggested that mktemp be used instead."
- How can a denial-of-service attack be carried out if a directory name is known?
- Why is it important to use mktemp to generate a sufficiently random file/directory name for temporary files?
Security :: Prevent Normal Users See All The Processes Running On The Box?
Dec 30, 2010I've a Linux box with few users (with shell). I would like to prevent normal users see all the processes running on the box. How can I implement this?
View 1 Replies View RelatedUbuntu :: Prevent The System From Powering Off
Jun 25, 2010Ubuntu randomly switches off. I eventually found out that it happens when my system is over loading. If my memory goes up to 100% use or CPU, Ubuntu powers off. If there some software that I can download to prevent my system from using 100% of its power, so it doesn't power off?
View 1 Replies View RelatedFedora Security :: How To Prevent The Appearance Changing Window Running
May 21, 2009I want to prevent users changing the wallpaper, as i couldn't found any direct method I thought of preventing the /usr/bin/gnome-appearance-properties being running,
I know that the user also can set the wallpaper without running that . But didn't found any other way .
I tried to use SELinux to it and I'm stuck at writing a own policy.
According to SELinux, it prevents everything ., but as i have mapped the user to a SElinux user ,even though he can use administrative tasks , he can run the appearance window. that means he has got the permission from a different policy , Currently I'm stuck at this place.
Suitable way to prevent the wallpaper being changed by the normal users.
Security :: Filter Pam_rhosts_auth Messages To Prevent The Logs Filling Up?
Mar 8, 2010I have a batch job which logs in to the server every 10 minutes via windows rsh. The job checks to see is there are any files that need to be send via a EDI serverto a supplier.The following logwatch report is swamped with the login messages and would like to either suppress the logging in PAM? or suppress the entry in the logwatch report?But I still want logging id the username is not username1.Connections (secure-log) Begin rshd[1754]: pam_rhosts_auth(rsh:auth): allowed to username1@10.0.0.1 as myedi
View 2 Replies View RelatedSecurity :: Prevent Users From Changing Or Unset Their HISTFILE Variable?
Sep 30, 2010'readonly HISTFILE'
but the user could tamper with the histfile itself. Like:
rm -f $HISTFILE;
rm -f $HISTFILE; mkdir $HISTFILE;
rm -f $HISTFILE; ln -s /dev/null $HISTFILE;
I'm experimenting with PROMPT_COMMAND to execute a command each time the user executes a command and so log it somewhere else.This post was pruned from the 2009 Is there a way to prevent users from changing or unset their HISTFILE variable? thread. Please do not resurrect old threads but instead create your own (and maybe provide a link to the old one).
Fedora Security :: New Glibc Update Make Selinux Prevent Qemu-kvm To Run
Aug 11, 2009After install glibc-2.10.1-4 (x86_64) package, i couldn't run the qemu-kvm anymore.
SELinux is preventing qemu-kvm (svirt_t) "setrlimit" svirt_t.
SELinux prevented pt_chown from using the terminal 0.
Ubuntu Security :: Grub With Luks Support - Encrypting The Boot Partition To Prevent The Kernel From Being Modified?
Mar 9, 2011Has anyone tried encrypting the boot partition to prevent the kernel from being modified. Iv tried following this but I'm running into issues when building. [URL] Im using the source from bzr checkout [URL] Last time I tried I screwed grub and it wouldnt boot.
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