Content related to computer security., i.e. content about policies, mechanisms, etc. needed make sure data is not leaked or corrupted and services available in all circumstances.

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3
votes
2answers
343 views

Prevent hacking the grub.conf using a 'live rescue' from a live linux iso

It happened that I had set the grub password in grub.conf. But, using a live linux iso, I was able to delete the password from the grub.conf. Please read the steps for the same mentioned in this link: ...
7
votes
1answer
202 views

Is it normal to have a file called “shadow-” in the /etc directory?

I am noticing a lot of weird files appearing in my router and on my various filesystems. Files in weird places or files that have to do with security with a - sign after them. If I do ls -l ...
4
votes
1answer
1k views

How to configure permissions to allow apache to securely have access to a file in a shared environment?

This is a follow up question from my previous, but I felt it might be more Linux based. http://serverfault.com/questions/414207/how-to-set-linux-permissions-to-allow-apache-to-have-access-to-a-file ...
3
votes
2answers
894 views

Is it possible for a CentOS system on EC2 to not have a bootloader?

I'm attempting to look for grub: [root /]# find / -iname "*grub*" /sbin/grubby /usr/share/man/man8/grubby.8.gz /usr/share/vim/vim70/syntax/grub.vim /usr/share/vim/vim70/ftplugin/grub.vim ...
3
votes
2answers
2k views

Protecting postfix from bruteforce attacks

a few days ago I've set up a VPS, including personal SMTP service using postfix + procmail under Debian / Wheezy. I am already seeing a LOT of hammering onto the SMTP and other ports. Here's an ...
5
votes
1answer
341 views

Automated ssh login with passphrase?

Logging onto a machine over ssh typically requires a password to be entered before access is granted. Alternatively, a key/certificate (without a passphrase) can be installed onto the remote machine ...
2
votes
0answers
192 views

When was this vulnerability fixed in Debian? (CVE-2012-2088 affecting libtiff4) [closed]

I have Debian Squeeze installed on my one of my workstation. On my Ubuntu 10.04 workstation there have been two security updates to the libtiff4 package in the last couple of weeks, addressing the ...
6
votes
2answers
1k views

Optimize performance for encrypted disk

Recently I tried to copy 200GB to a 1TB external / USB2 / encrypted disk and it took 36 hours. The same copy when the disk was not encrypted took no longer than 1 hour. I am using dm-crypt (LUKS) ...
2
votes
2answers
155 views

need explainations on this network route

I'd like to get some insight as to how I can possibly access network devices that are on a different IP range (obviously not mine) compared to what is configured on my wifi router? setup home wifi ...
12
votes
2answers
37k views

SSH key-based authentication: known_hosts vs authorized_keys

I read about setting up ssh keys in Linux and have some questions. Correct me if I'm wrong… Let's say host tr-lgto wants to connect to host tr-mdm using ssh. If we want to be sure that it's the real ...
3
votes
2answers
387 views

Can AIDE scan a directory inside a directory the user doesn't have read permissions for?

I would like to use AIDE to help me verify the integrity of my home directory on a shared Linux system. I am not an administrator of this system. I have built and installed AIDE in my home directory ...
1
vote
2answers
94 views

Linux VPS Configuration

I just recently got my hands on a linux (Fedora) VPS and I would like to ask if there are special configurations that I have to be wary of. Do I still configure it like I would configure a normal ...
8
votes
2answers
18k views

Effect of entries in /etc/securetty

By default on RHEL 5.5 I have [deuberger@saleen trunk]$ sudo cat /etc/securetty console vc/1 vc/2 vc/3 vc/4 vc/5 vc/6 vc/7 vc/8 vc/9 vc/10 vc/11 tty1 tty2 tty3 tty4 tty5 tty6 tty7 tty8 tty9 tty10 ...
0
votes
1answer
150 views

knock on Scientific Linux 6.1? (perl script for knocking?)

I have an OpenWrt router where I installed knockd: knockd.conf [options] logfile = /var/log/knockd.log [openSSH] sequence = 7000,8000,9000 seq_timeout = 5 command = ...
7
votes
1answer
268 views

Why is it a security problem to have /usr/sbin owned by bin?

The Sendmail Installation and Operation Guide (§1.3.1) asserts: For security reasons, /, /usr, and /usr/sbin should be owned by root, mode 07552[...] 2Some vendors ship them owned by bin; this ...
3
votes
3answers
713 views

Is encrypting your web browsing via SSH to localhost useful?

For example, if I did an ssh -X to localhost and invoked Firefox, would that be enough to be considered safe browsing, like if done on some public wifi?
5
votes
2answers
2k 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 ...
5
votes
2answers
2k views

Preventing access to TTY when X is killed

Assume I start an X server manually from a virtual console /dev/tty1 with xinit or startx, with the line id:3:initdefault: set in /etc/inittab. The X server gets run and put on another virtual ...
3
votes
2answers
1k views

fprintd-enroll works with right-index finger only

When I try any other finger with: %> fprintd-enroll left-index-finger Using device /net/reactivated/Fprint/Device/0 failed to claim device: Not Authorized: ...
3
votes
1answer
94 views

Encryption of home directory for securing data after harddisk corruption

Always when I install Linux OS (e.g. Ubuntu), there is a possibility to encrypt the home directory. I was asking myself why is this useful. Is it good in the case when my harddrive is corrupted and I ...
1
vote
2answers
877 views

Can someone change content of a file with permission 777 on a server?

If in my server I have a file(for example a php file) with permission 777, can someone edit or delete it without having an account on the server?
0
votes
1answer
1k views

What is the default encryption type of the ssh-keygen?

When generating private/public keys with ssh-keygen what types of keys will it generate if I wont pass -t option followed with the encryption type like rsa?
4
votes
1answer
556 views

Why do SELinux policies require a system restart?

When changing SELinux policies, I've been reading that you're required to restart the system. What changes would require this? Are there certain policy changes that would not require a restart?
2
votes
3answers
942 views

Is there a good way to encrypt and store a mailbox while still being able to quickly access and search it?

I am wondering if it is possible to : Store a mailbox in a way that the system administrator (ie: root) cannot see it User(s) with the valid credentials would be able to see it AND be able to search ...
23
votes
4answers
70k views

SSH login with clear text password as a parameter?

I need to login to a user that I've created on a remote host running Ubuntu. I can't use an ssh key because the ssh login will happen from a bash script ran within a server that I won't have access to ...
3
votes
1answer
2k views

See if file has been copied to USB

Is there a way to see if a file has been copied to an USB drive? (Ex: I have the file secret.db and I suppose that my friend has copied it into his USB drive. With stat $filename I cannot see the ...
3
votes
1answer
499 views

How to check downloaded package on OpenBSD 5.1?

Under linux there is a package called "ubuntu-keyring" - it's for checking that the downloaded packages (from the offical repositories) are the ones that are on the server. How can I do this under ...
4
votes
5answers
21k views

vsftpd fails pam authentication

Moving a tried-and-true vsftpd configuration onto a new server with Fedora 16, I ran into a problem. All seems to go as it should, but user authentication fails. I cannot find any entry in any log ...
10
votes
2answers
3k views

Should you run automatic updates

I'm running production Centos web servers. I want to know what is best practice for running updates. Should I automate this with yum-cron or yum-updatesd? Or is there a danger of updates breaking ...
4
votes
2answers
1k views

How to set secure permissions for multiple users and multiple websites?

On a Gentoo 3.2.12 server with apache2+php, there are several websites running: /www /website1 /website2 ...etc The apache user should have read-only access to all the websites. There ...
3
votes
2answers
322 views

Linux security vulnerabilities?

A while back I started an embedded project using the 3.2.10 kernel. Now the project should go into production and the stable kernel is 3.2.16. I would prefer not to upgrade anything to avoid ...
4
votes
3answers
7k views

Fork bomb on a Mac?

I just learned about a fork bomb, an interesting type of a denial of service attack. Wikipedia (and a few other places) suggest using :(){ :|:& };: on UNIX machines to fork the process an infine ...
1
vote
0answers
309 views

Information about the 1630/master app

When I run $ sudo netstat -a --programs | grep LISTENING | grep 1630 I will get this output. Do you know what good are processes running under this app name? Why they I running on my system and if ...
1
vote
3answers
287 views

How can I identify processes that use network facilities, and can they be killed?

In the output of netstat -a | grep LISTEN there are usually a lot of processes. How (where) can I find out information about them, what is their purpose in the system and if I can kill them? Which ...
10
votes
2answers
700 views

How do I prevent programs from sniffing keystrokes to su/gksu?

I've read here that it's possible for any app using the X server to sniff keystrokes to any other app which is also using the X server, including su (on a terminal) or gksu. I've heard of a few ways ...
1
vote
1answer
517 views

How to know who accessed a file or if a file has 'access' monitor in linux

I'm a noob and have some questions about viewing who accessed a file. I found there are ways to see if a file was accessed (not modified/changed) through audit subsystem and inotify. However, from ...
1
vote
4answers
167 views

Erasing HDD , re-write only headers , is that safe?

I want to erase my HDD quickly with dd, so If I only "zeroify" the partition headers , like destroy the inode table, block size etc. But is that safe? UPDATE I have some partition not encrypted ...
2
votes
2answers
679 views

Is xinetd still the best method to let non root daemons listen on privileged ports?

When I need to use SNMP monitoring for java applications, there is the need to that application (usually ran as daemon user) to listen on snmp port. If there is no other alternative, of course I can ...
4
votes
2answers
1k views

Arch: Is “SigLevel = Never” the only convenient way?

The only way I can install majority of packages without rejection from signature database is to put SigLevel = Never in pacman.conf. Its not supposed to be the right way, but I don't seem to be able ...
1
vote
1answer
120 views

A tool that helps me to be sensible on permissions?

Is there a tool or understandable source (manual, webpage, ...) in existence that helps a moderate* user to be more sensible about user permissions? In my ideal-dream-world I'd have a CLI tool that ...
2
votes
1answer
292 views

dm-crypt and LUKS password rotation

How do you protect the master key, and distribute multiple passwords for admin access? Is there a 3rd party user management tool or is this native?
1
vote
1answer
453 views

How do I hide login information passed to command line programs from appearing in the process list?

I have to execute a program that passes in as command line options the username and password. Is there a way to hide the username & password from appearing in the /proc entry for this process.
9
votes
3answers
2k views

Is it safe to close shell just by clicking “X” or using “ctrl+d”?

Is it safe to close shell just by clicking "X" or using "ctrl+d" while logged in as root with su or is it safer to close it by typing "exit"? Is there any difference (security-wise) at all or is it ...
3
votes
1answer
197 views

How are loaded SSH keys referenced by name?

I'm using chef's knife ec2 tool which requires the name of a loaded SSH key (that was created in the Amazon EC2 control panel) It seems strange to me that it uses a name to reference the keypair - ...
1
vote
1answer
258 views

Hamachi for Web Surfing

I recently installed Hamachi on my FreeBSD 9 and I want to know how can I browse web anonymously by this software?
3
votes
2answers
98 views

In Gnome, how do I decide whether to accept a PackageKit software source?

When I try to install software in the Gnome environment of Linux (mine is openSUSE) from a repository that I have not used before, PackageKit asks me to respond "Yes" or "Cancel" to a dialog "Software ...
-2
votes
4answers
262 views

Steps to secure your server? [duplicate]

Possible Duplicate: What to use to harden Linux box? Apparmor, SELinux, grsecurity, SMACK, chroot? I'm just completed install my web server. So what should i do to secure it? I just ...
6
votes
1answer
1k views

Jailbreaking HDTV

I have a Vizio internet TV, the predecessor to this one with basically the same specs, not 3D though. I wanted to try and gain root access to the tv. Using nmap I leaned that the only port open is ...
3
votes
2answers
247 views

SSH Bash Jail Session

I've seen some game tunneling service providers that jails the customer's account to a Information screen upon login and any input is ignored. Ctrl+C closes the SSH session, and disconnecting. This ...
1
vote
2answers
1k views

Allow non-root process to access all home directories without compromising security?

Any ideas how to allow one non-root process to access (read&write) all home directories without compromising security? Normal users should not have access to each other's home directories. All ...