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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247 views

Creating linux distro for use during exam

I'm thinking about creating a liveCD having some linux on it. The distro (let's call it Exam OS) is meant to be used by students during an exam and should be, at least, unpleasent to bypass. Let's ...
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3answers
645 views

Why does time/ident/daytime/comsat run after an OpenBSD 5.2 install?

I installed an OpenBSD 5.2 using "-* & +etc* & +base* & +bsd". After finished with the install, I rebooted, then netstat -at | grep LISTEN, this is what I get for output: Why does so ...
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2answers
1k 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 ...
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2answers
2k views

Use wpa_supplicant without plain text passwords

I'm running gentoo on my laptop, and I'm currently using wpa_supplicant to handle wifi. My configuration works and I can connect, but it is required to type in the plain text password into the ...
5
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1answer
48 views

Sterilize PDF files

I use Linux on my desktop, but I got suprised after checking random PDF files on my machines with Virustotal. One of them contained a "PDF.Exploit.CVE_2008_2992". So PDF files can have malicious ...
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1answer
507 views

Save password in bash script for multiple queries

I would like to know if there is a safe way to only be queried for a password once in a custom bash script, and then save it somehow to be used for later needs. At the end of the script it should be ...
5
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1answer
252 views

Secure access to remote SSH tunnel

So I wish to be able to access my Raspberry Pi (which I keep at home behind a firewall) remotely. One option is to use a static IP address, but as a poor student I don't want to fork out for one, and ...
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1answer
604 views

Ubuntu: If anyone can get a root prompt without password, isn't that compromising the gnome keyring?

I've been looking for this for quite a while now but couldn't find a satisfying answer. My scenario: I'm using encfs to encrypt a few directories in my home folder. To make it easier to access I set ...
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1answer
623 views

What are EXT4 Security Labels?

During Gentoo installation of Gnome keyring, I am told to switch on EXT4 Security Labels, which is described in the kernel documentation by: Security labels support alternative access control ...
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1answer
3k views

Linux: LUKS and multiple hard drives

I have a Debian Linux system (amd64) installed on a RAID-1 system encrypted device (LVM on LUKS) and will have a RAID-6 of >=4 disks where I'll put my data (LUKS and maybe LVM). I think the basic ...
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4answers
499 views

Allowing rename but not moving to other directory

Users can upload/delete/rename files via vsftp server and everything works well except they can also move files across directories. Is it possible to allow renaming of files but disallow moving them ...
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1answer
1k views

Which home directory should 'nobody' have?

I'm messing around with Tiger security audits on my CentOS box, ensuring the server is fit for being online, well as close as it can get anyway. I noticed a warning about the user nobody having / as ...
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1answer
177 views

OpenBSD and limiting login to local only like in FreeBSD's login.access(5)

I am using OpenBSD as my desktop. I don't want to login to my machine remotely, and I don't want anyone else to login remotely. In FreeBSD there is a file called login.access(5) that can be used to ...
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2answers
1k views

Can KWallet manage my ssh passwords?

I need a way to store some SSH passwords. Note that these are login passwords which I need to pass to ssh; key authentication is unfortunately not an option. I'd like to be able to have KWallet fill ...
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2answers
2k views

Hide processes from other users based on groups (under Linux)?

Is it possible to configure process hiding for certain user groups under a linux system? For example: Users from group X should not see processes owned by users from group Y in ps/top or under /proc. ...
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0answers
77 views

Does Android's implementation of SELinux's M.A.C. inhibit root apps with root privileges from accessing app data? [closed]

Starting with Android 4.4 SELinux's MAC is enforced. Does this mean that if an app somehow can get installed and exploit the kernel to get root privileges, that MAC will still prevent that app with ...
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1answer
63 views

Can swap be encrypted per user?

The problem arises for a multiuser computer with encrypted swap, as to how to allow each user to hibernate and resume from hibernation without compromising the security of the other users. I'm ...
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1answer
307 views

gdm greeter configuration: Exclude all *except* for one specific user

I have Googled this one and tried so many combinations, with no success. I need the GDM login greeter to display one and only one username. In effect, what I need is something like this in ...
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1answer
36 views

Need More Information About KDE Job Notification

I installed Debian 7.2 on a new laptop a couple of days ago, and now I'm getting a strange job notification every once in a while. It just says the following: Source: ...
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3answers
1k views

Stracing su and ssh shows the password. Is this a security flaw or am I missing something?

I'm currently fascinated by strace so, being new to it, I decided to play around a little. As suggested by the question title, I tried both strace su and strace ssh. Both commands displayed the ...
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3answers
432 views

Securely feeding a program with a password

After understanding the problem with using a password in the command line, I need to find a way of feeding a program with a password without it being a problem (without the password being recorded ...
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2answers
193 views

Why rejection of password is much slower than acceptance of it? [duplicate]

In both my Linux and OSX machines when I type in the password to login, a correct password is accepted immediately. However, if I type a wrong password, checking process takes much longer. How is ...
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1answer
3k views

What audit log files are created in linux to track a users activities?

One of the machines on our networks was consuming a large amount of Internet bandwidth. However no user was using the system. When I connected to the server using SSH and ran who it showed that a ...
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3answers
577 views

Hidden Files&Directories in user's home directory [closed]

I am in my user's home directory, I do: ls -a Then it shows me large number of hidden files and directories in my user's directory. Which of them I am allowed to remove? Which ones are necessary ...
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2answers
3k views

How do you protect a plain text credentials file with the username and password?

I am trying to setup an auto-mounting network drive. The network drive requires a user/pass. In the man page for "mount.cifs" there are two ways to provide the user/pass. [not recommended] put the ...
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5answers
157 views

Hiding work in account with multiple users

I'm currently working on an assignment in a cluster programming class. The class has been given an account on the cluster, so we can ssh in and do our work. The problem is that the one account is ...
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4answers
345 views

SSH to untrusted machine

If I SSH to a remote server, is it be possible for the admins of that machine to use my SSH session to send data back down the connection and do something to my local PC? I use DSA keys and do not ...
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3answers
390 views

Something like pwgen-win for linux?

Is there some kind of pwd generator for Linux that has a nice GUI and options like this one for Windows? I know that there is pwgen, but as far as I know it does not support mouse/keyboard entropy and ...
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2answers
2k views

how to know the type of symmetric encryption used by ssh?

I want to know the type of symmetric encryption (after authentication) used by ssh in a connection client-server. I'm not sure who determines the encryption. Client or Server?. I have looked in ...
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2answers
749 views

Purpose of using setuid() in SUID programs

I wonder that an SUID program like passwd is using the setuid() function call. Why does it drop root privileges? Against what types of attack does this help? Buffer-overflow?
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1answer
232 views

What's the best way to configure shared filesystem directories? (beyond standard unix perms)

I have multiple users on my system. I'd like to have shared directories like music, video. pictures etc. The problems is that I want users to be able to write any new files to any directory, but not ...
4
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2answers
213 views

Finding the logs in a hacked server. [closed]

My server has been hacked and the hacker managed to ssh as root (I know, horrible mistake on my part). What files should I be looking for to discover the origin of the attack? (At least their IP). ...
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3answers
588 views

Logging when limit Exceeds

Is there a log file that logs information when the values set in /etc/security/limits.conf are exceeded? If not is there a way to make it log when the values are exceeded?
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1answer
2k views

Sign a module after kernel compilation

I've built a kernel in tmpfs, then I rebooted. Now I see a message when I compile the 3rd party module, NO SIGN [M] XXXX.ko How can I get it signed? The key pair generated during rpmbuild is lost ...
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2answers
3k views

what is OS hardening in linux or unix?

The term OS hardening itself is misleading/vague to me as i am reading to understand it online here. It seems to me that its something related to making linux/unix box more secure.
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3answers
372 views

Monitor all login attempts

Few weeks ago I thought it would be a good idea to write a script to send me an email whenever some user logs in into my server. So I came with a perfectly working script notifyLogin.sh, then I ...
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3answers
822 views

Running Viber as another user while using “mine” X Server's microphine and speakers

I run Fedora with GNOME and recently installed Viber for linux. It's very good and all is working just fine. As Viber is not open-source software, I decided to run it as another user to make sure ...
4
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2answers
399 views

How to get a usable full disk encryption with different encryptions for different users

I want to have a full system encryption on my laptop. But I have two users, one for home and one for work and want a separate encryption for both. Sure I could do a full disk encryption with dm-crypt ...
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2answers
104 views

Fully seperate two accounts without installing seperate operating systems?

Our class is finally installing Mint Linux on our machines. The problem is our teacher is scared that we'll play war games against the two classes that use the computers. His solution is to install ...
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3answers
1k views

Is it impossible to run as `root` if the machine isn't rooted?

By default, the user of the device does not have access to certain root objects (e.g. the /data directory). Even though these objects are off-limits, however, it would seem to me that these objects ...
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6answers
469 views

Any program like `sudo` to gain root by having two users enter a password?

I run a server which is used by a group of individuals for e-mail, mailing lists, personal web homes etc. I thought about ways to provide root access for other members to allow them handling problems ...
4
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1answer
195 views

How does iptables recognize packet state?

Consider these two sets of rules: Set A -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT -A INPUT -j REJECT -A OUTPUT -j ACCEPT Set B -A INPUT -m conntrack --ctstate ...
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2answers
111 views

What are the methods to protect home folder files from other applications runing as the same user?

I would like to enforce the security access of some files in my Home folder. My concern is about processes running with the same privileges as me having access to those files. I've been wondering ...
4
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1answer
693 views

How can I secure my Ubuntu 13.04 to prevent network attacks? [closed]

Is there a way I could protect my pc computer from being hacked in an event where the internet conection will be opened? Thing is I am going to Campus Party Colombia 2013 and I was sugested to format ...
4
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3answers
1k views

Why is PATH reset in a sudo command?

After much frustrating head-brick-wall contact, I've discovered this: $ echo $PATH /usr/local/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/sbin:/home/steve/bin $ sudo bash # echo $PATH ...
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2answers
154 views

Linux Kernel limit access to root with a button?

Is it possible to limit the access to a root account from within the kernel? I mean that if I press a button then the system detects the button being pressed and then allows access to the root ...
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1answer
118 views

Are there any security risks when mounting as root?

Are there any security related risks when mounting with root privileges compared to mounting with regular users? I have a script which does some ecryptfs mounting with non-root privileges (by design), ...
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2answers
7k views

Avoid “Authentication token manipulation error” on password change

I'm implementing a security policy that will force the users to introduce stricter passwords when they change their own: The /etc/pam.d/passwd configuration file is: #%PAM-1.0 auth include ...
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3answers
199 views

Can someone execute a malware by just inserting a flash disk?

I know that Linux is virus proof, but just to be sure...Suppose someone writes a script, trojan, etc... and put it on a flash disk or CD. then I insert that flash in my system without clicking on any ...
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3answers
451 views

Is a command's stdout to the terminal being logged?

I am interested in learning whether a command's output to the terminal is logged somewhere. Since that can be a bit too generic, what about cat (and ccat) in specific? If I use cat on a file, will ...