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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2
votes
1answer
173 views

Can I lock the root account during an install of Debian GNU/Linux 6 “squeeze”?

By default, Ubuntu locks account root; can I do the same, in Debian GNU/Linux 6 "squeeze", during install?
2
votes
1answer
943 views

su-to-root fails when root user locked?

How might I use script /usr/bin/su-to-root after I have intentionally locked the root account? Running Debian GNU/Linux 6.0.5 "squeeze" and noticed menu item "System > Administration > Synaptic ...
1
vote
1answer
609 views

Make bluetooth device invisible / disable incoming pairing

I am using the bluez package for my bluetooth usb dongle on ubuntu server. I want to be able to initiate bluetooth connection from the dongle to a device, however a device itself shall not be able to ...
4
votes
1answer
118 views

Can I force myself to enter a password when run certain processes?

I frequently work in an environment where, lets call them "pranksters" may gain access to my console. I am diligent in locking my screen whenever I walk away, but given enough time someone gets the ...
9
votes
3answers
454 views

Physically break into box? (Memory & disk)

I have a VPS. I might be able to encrypt my partition but I havent tried. My VPS company I believe can reset my root password although the only SSH key I see is my own. With all my data I have it ...
1
vote
1answer
1k views

Safety of SMB versus SFTP

I have a server with OpenSSH enabled. I use it to make distant backups. I mainly use rsync over SSH and SFTP. I understood that these protocols are quite safe. I am interested in enabling Samba share ...
3
votes
3answers
454 views

Prevent users from killing processes that they own

I have started some processes (window based) from user's .bashrc file. I want to prevent users from killing those processes. Is there a way to transfer the process to superuser so that a normal user ...
4
votes
1answer
417 views

In my secure log there is a new group added that Im unsure about after adding semanage

I installed semanage onto my CentOS 6.2 box and I was going through my secure log after the install and noticed this entry: Aug 31 22:12:17 xxxx groupadd[12929]: group added to /etc/group: ...
3
votes
1answer
2k views

Can I automate mounting a cifs share without storing my password in plaintext?

I currently use a script which contains commands along the lines of sudo /sbin/mount.cifs $SERVER_SHARE $MOUNT -o username=$DOMAIN_$USER,uid=$USER,gid=$USER,file_mode=0664,dir_mode=0775 to mount my ...
2
votes
1answer
716 views

Is it *really* possible to directly steal a private key if it uses no passphrase?

I've read in various places, such as in this question that using an ssh key pair without a passphrase allows attackers to steal your private key if they gain access to your account. I assumed that by ...
7
votes
1answer
5k views

Is there a way to deactivate Buffer overflow protection on my machine?

I want to do some experiments with buffer overflows on my various virtual machines, including (but not limited to) Debian 6, Ubuntu 12.04, Fedora 16, but every time I try to execute the buffer ...
2
votes
4answers
4k views

Allow paswordless user to change to another passwordless user

I have two users dev and tomcat neither of them have a password. How can I allow dev 1 do su - tomcat without having him having to enter any credentials? 1 connects with ssh keyfile
11
votes
7answers
3k views

When does the Puppy linux security model make sense?

I have just spent a few hours playing with Puppy linux, which has some very nice features, but there are some things about its approach to security (at least the default settings) that worry me: It ...
8
votes
5answers
2k views

Read and confirm shell script before piping from curl to sh (curl -s [url] | sh)

Whenever I have to execute a shell script from the web curl -s [url] | sh, I first open url in my web browser to make sure the script isn't malicious and is safe to run. I remember seeing a command ...
1
vote
1answer
686 views

How to provide a “guest LAN” on one ethernet device

I have an always-on machine running Debian/Squeeze with a couple of ethernet ports (it's doing various serverish jobs, including DHCP) and a LAN on each. eth0 is on 192.168.7.* and has access to the ...
2
votes
2answers
144 views

SSH encryption security

If I log in to my server through ssh and copy files to my local computer can I be eavesdropped? How do I make sure nobody can intercept the data or even know what I am copying? Are there levels of ...
3
votes
2answers
336 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
198 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
822 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
324 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
191 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
153 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
32k 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
376 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
93 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
17k 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
148 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
265 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
694 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
1k 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
93 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
849 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
517 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
909 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 ...
21
votes
4answers
61k 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
493 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 ...
3
votes
5answers
20k 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
959 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
316 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
6k 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
293 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
275 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 ...