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
3answers
282 views

True HTTPS? How?

/Using Google Chrome/ if i visit: https://secure.wikimedia.org/wikipedia/en/wiki/File:Nokota_Horses_cropped.jpg then the: ...
5
votes
1answer
4k views

What is hvc0? (appearing in “who” list)

I have an Ubuntu Server, and when I type who, to see who's connected, I can see that there's a user connected, and instead of being logged to a pts/x, he's connected to hvc0. Is there something to ...
4
votes
2answers
4k views

Can I create a local only guest account?

Is it possible to create a "guest" account in Linux? by "guest" account I mean an account that does not require a password to log in graphically. I want this account for when people come over and are ...
35
votes
7answers
27k views

What's the difference between /sbin/nologin and /bin/false

Technically, unless pam is set up to check your shell with pam_shells neither of these can actually prevent your login, if you're not on the shell. On my system they are even different sizes, so I ...
4
votes
1answer
812 views

Linux - why is kernel.shmall so low by default?

I run DB2 on Linux where I have to allocate the vast majority of memory on the machine to shared memory segments. This page is typical of the info that I've found about shmall/shmmax: ...
6
votes
1answer
1k views

Lock screen w/ slock after a certain time?

I am running OpenBox in Arch Linux, how can I set it up so that I can have slock lock my screen after a certain amount of time (with no activity)? Thanks!
2
votes
2answers
902 views

GPG check regarding packages on various distributions

It's ok that the various linux distributions use gpg to verify e.g. new packages downloaded with http. But what happens if the server that holds the packages gets hacked? OK, they need a new gpg key, ...
11
votes
7answers
2k views

How do I encrypt git on my server?

Heres the closest I've gotten: I installed gitolite in the /Private folder using ecryptfs-utils (sudo apt-get install ecryptfs-utils adduser git ecryptfs-setup-private then the rest was configuring ...
0
votes
0answers
145 views

git and remote security with Encfs [duplicate]

Possible Duplicate: How do i encrypt git on my server? I wanted to create a user on my server to use as a private repository. I'd like the files to be encrypted. Encfs will timeout after ...
2
votes
1answer
113 views

Is it safe to leave a enc folder mounted?

I was looking at this and ecryptfs seems cool. I'd like to use it on my server to encrypt git pushes. I dont want to ssh in everytime to mount/unmount the encrypted folder. However once in a while ...
2
votes
4answers
684 views

How to guarantee the integrity of an OS?

In information security, integrity means that data cannot be modified undetectably. This answer raised my interest, of course, I want to guarantee the integrity of my OS, outlined here. ...
7
votes
4answers
349 views

How can I safely give a shell to somebody?

I have a question about giving a shell account to somebody. How safe is it? He could read /etc. How can I give a secured shell account that will only restrict the user to some bins and his own home? ...
7
votes
2answers
230 views

Hibernate and security considerations

How do Linux and OSX handle sensitive memory pages (e.g. cryptographic keys) when running OS is suspended to disk? If the memory image written is encrypted, how are its keys handled?
3
votes
1answer
2k views

Privoxy redirect rule for Wikipedia

I have a few Privoxy rules, that can redirect HTTP Wikipedia [en,de] traffic to HTTPS: (a little part from the "user.action" file) { ...
0
votes
2answers
529 views

Is there a Debian security APT repository that allows access via ftp?

If I want security updates for Debian, I add the following line to /etc/apt/sources.list: deb http://security.debian.org <codename>/updates main Is there a repository that allows the http to ...
13
votes
3answers
6k views

How should one set up full-disk encryption on OpenBSD?

Is there a preferred method to set up full-disk encryption under OpenBSD, similar to dm-crypt under Linux? I'm looking for full-disk encryption, as if someone were to steal my notebook they could ...
3
votes
1answer
3k views

Can a user with /sbin/nologin shell login through ssh?

Is it possible to ssh to a machine as a user with no valid shell (say, mail)? So far I cannot, and using the command below doesn't work: $ ssh mail@machine.local /bin/bash It will always say "This ...
3
votes
3answers
276 views

Turning an old computer into a network firewall

I have an old Dell Dimension with two ethernet cards, and I need to turn it into a firewall. I've tried FireStarter and IPCop, but I don't think I'm setting them up right. Here's the setup that I'm ...
11
votes
2answers
2k views

Does SELinux provide enough extra security to be worth the hassle of learning/setting it up?

I recently installed Fedora 14 on my home pc and have been working on setting up different server related features such as apache, mysql, ftp, vpn, ssh, etc. I ran extremely quickly in to a barrier ...
5
votes
2answers
700 views

make a 2nd root?

I was thinking, maybe i'd like to disable passwords for the root user and only use keys to log in. and if i need to login without keys have a 2nd user that is like root in everyway except has a ...
2
votes
2answers
237 views

What is the “Online Certificate Status Protocol”?

I use privoxy. In the user.action file i have a redirect rule and a few websites: { +redirect{s@http://@https://@} } .twitter.com .facebook.com Ok! it's working great, e.g.: if i visit any ...
3
votes
2answers
335 views

Recommended way to login to root?

After I found out hundreds of hacking attempts are made in a day I decided I want to disable logging in to root remotely via a password. But then I found I can't switch users in WinSCP so I can't ...
5
votes
2answers
5k views

How do I disable remote root login via ssh?

How do I disable remote root login via ssh? I want to log into my server (I use keys on my main comp) then su into root instead of access root directly. I am using Debian. I follow guides online ...
2
votes
3answers
920 views

Is there any chance that some of these processes are malicious?

My significant other and I are sometimes paranoid that a foreign government usually associated with last year's Gmail security breach may be attempting to gain access to our computers. There were a ...
3
votes
2answers
954 views

What directories/file permissions should i ensure are set?

I have a similar question about default software configuration. For this question i would like to ask What directories/file permissions should i ensure are set? Aprrently Is it normal to get ...
9
votes
1answer
436 views

Is locking the screen safe?

See USB driver bug exposed as "Linux plug&pwn", or this link Two choices [GNOME, Fedora 14]: Use the gnome-screensaver Use the "switch user" function [gnome menu -> log out -> switch user] ...
4
votes
1answer
2k views

How can I configure SELinux when the semanage command isn't found?

I'm having a very hard time configuring SELinux to allow Sending mail. Looking into selinux documentation I've found I can manage ports via the semanage command, but the command can't be found. Is ...
2
votes
1answer
1k views

Ideas for securing OpenVPN on an OpenWrt router

I put an OpenVPN server on port 1194 on an OpenWrt 10.03 router: echo "nameserver 8.8.8.8" > /etc/resolv.conf; opkg update; opkg install luci-app-openvpn openvpn openssl-util openssh-sftp-server ...
2
votes
1answer
3k views

How to connect to OpenVPN with NetworkManager

I have installed an OpenVPN server on my OpenWrt 10.03 router [freshly flashed]: https://pastebin.com/raw.php?i=hRECWuf1 echo "nameserver 8.8.8.8" > /etc/resolv.conf; opkg update; opkg install ...
0
votes
2answers
138 views

Where to handle packets between clients?

"Server": 192.168.1.1 I want to "theoretically" disable that the clients can "ping" each other. Can i use an iptables rule for it? e.g.: iptables -A FORWARD -m iprange --src-range ...
2
votes
1answer
206 views

tripwire report - inode number

Hi I am investigating tripwire and have stumbled upon something which i am unsure about. in a tripwire report generated after i modified hosts.deny to include an extra # I noticed the inode number ...
1
vote
1answer
1k views

IPTABLES rule for separating users

I have an OpenWrt 10.03 router [ IP: 192.168.1.1 ], and it has a DHCP server pool: 192.168.1.0/24 - clients are using it through wireless/wired connection. Ok! Here's the catch: I need to separate ...
82
votes
7answers
11k views

Which is the safest way to get root privileges: sudo, su or login?

I would like to have the root account in safety even if my unprivileged user is compromised. On Ubuntu you can only use sudo for "security reasons" by default. However I am not sure it is any safer ...
17
votes
3answers
1k views

Is it secure to leave a root shell running in detached screen session?

I'm curious about the security of leaving a root shell running inside a detached screen session. I typically never do this. Aside from the potential of my non-root user account being compromised ...
1
vote
1answer
126 views

Default configuration I need to change?

A few days ago I installed a new linux os. Today i realize /root has o+r (755) so EVERYONE is able to see my root sql password in /root/.my.cnf. I freaked out and simply changed /root to 750. My ...
1
vote
2answers
510 views

How can I disable /proc pseudo-filesystem on a shared Linux environment?

Is it possible to disable the /proc pseudo-filesystem to prevent w, ps, top, etc, from showing what other users are doing? Of course, I still want "everything else" to work correctly. Is there a ...
19
votes
3answers
811 views

Can other users view the arguments passed to a command?

If I invoke a command with arguments like so: bob@bob-pc:~$ command -arg1 -arg2 ...can other users view the arguments passed to the command?
3
votes
1answer
203 views

Is there a standard way to configure what policy iptables loads on startup under Debian?

I've just started playing with Debian 6.0 (Squeeze) in a VPS environment, as a way to learn more about system administration. One thing I'd like to configure is a default packet filtering policy. ...
5
votes
1answer
727 views

Why root's default shell is configured differently with other normal user account's default shell?

As I know, root's default shell is configured csh and normal user's default shell is sh in FreeBSD. And in Ubuntu, root is dash, normal user is bash. (refer: What's the Ubuntu's default shell?) Why ...
6
votes
2answers
3k views

Write to a file without redirection?

I am writing a regular compiled application that needs to create a special file and write a magic cookie into it. I can’t write the file directly from the application, the system security model ...
1
vote
1answer
157 views

What are the cons of posting dmidecode output publicly?

I remember somewhere mentioned that posting dmidecode output publicly is risky (security/privacy).
5
votes
3answers
204 views

I'm moving up from managed hosting to a VPS. What do I need to know?

I'll be starting to use a VPS for my web hosting this week, which is a big step-up for me since I've only used managed/shared services before. I've a bit of experience with Linux and I'm not afraid of ...
2
votes
1answer
1k views

How do you derive the passphrase from hexadecimal wep key?

I have a hexadecimal WEP key in the setting of my router. When I try to connect, the system asks me for the WEP passphrase. How can I derive it from my hexadecimal? This is what I have: ...
5
votes
1answer
3k views

What happens when your password expires and you're using key authentication?

on one of the boxes I don't control at work I use ssh keys to log in. Our passwords are set to expire after a few months. What happens if I don't reset my password and it expires? will I still be able ...
35
votes
4answers
4k views

Is there any way to keep a command from being added to your history?

Is there any way to keep a command from being added to your history? I have a command that I want to keep out of my history file, and I really don't care to have it there when I search the history ...
5
votes
3answers
464 views

Unix users, groups, and permissions

I don't understand unix users, groups, permissions, etc. For example, things managed by the chmod, chgrp, usermod, groupadd, etc. commands. How do all these things work?
5
votes
1answer
2k views

GNOME-keyring KWallet integration?

I use some GNOME apps, and some KDE apps, so some of them use G-keyring and some KWallet... What I would like to have is a single place for managing passwords. Is there a way to integrate G-keyring ...
4
votes
1answer
129 views

How can I run keychain in a way that only has the first shell prompt for keys on startup?

I open multiple shell tabs when I start KDE, and I've just added keychain to my ~/.shellrc the problem is that all the tabs prompt for key passwords when I login. This is quite annoying to do this. Is ...
7
votes
7answers
1k views

Is there a way to store Firefox passwords in a local encrypted database in Linux?

I want Firefox to "remember" my passwords so I don't have to type them in; unfortunately, the built-in password manager stores them in plain text, which is too high a security risk. I'd like to find a ...
14
votes
4answers
445 views

What specific vulnerabilities am I creating by disabling the sudo password?

Here are some instructions on how to disable your sudo password. These carry the following warning If you disable the sudo password for your account, you will seriously compromise the security of ...