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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2answers
12 views

Securely making an SSH connection from a public computer

Today, I had to remotely connect to my debian computer at home to fix an issue with a VPN server. I was using my iPhone with an SSH client to fix the issue, but I had a hard time due to the small ...
8
votes
2answers
112 views

Security implications of running perl -ne '…' *

Apparently, running: perl -n -e 'some perl code' * Or find . ... -exec perl -n -e '...' {} + (same with -p instead of -n) Or perl -e 'some code using <>' * often found in one-liners ...
2
votes
1answer
20 views

enable echo service and linux security loophole issues

in order to enable the echo service we need to add the echo lines as the following example : more /etc/inetd.conf echo stream tcp nowait root internal echo dgram udp wait root ...
4
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2answers
191 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 ...
2
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3answers
3k views

Moving /var, /home to separate partition

I am attempting to move some folders (such as /var and /home) to a separate partition after reading this guide: 3.2.1 Choose an intelligent partition scheme I was able to move one folder ...
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2answers
19 views

What does this host means ' ::1 '

To secure my mysql server, I checked the list of users : mysql> SELECT User,Host,Password FROM mysql.user; +------------------+-----------+-------------------------------------------+ | User ...
4
votes
1answer
28 views

PF's keep state on UDP packets = security issue?

During the last few days I've read a lot about PF as a nice alternative to iptables and a much more improved and secure way of filtering. Nevertheless I came across the following statement which I ...
0
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0answers
19 views

Reading Suricata log files with Barnyard or Wireshark

I have Suricata 2.0.3 running on CentOS 6.5. It generates files that I cannot read. I have read that two options for reading the log files (in unified format) are barnyard and WireShark. I ...
3
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1answer
381 views

Is there any DLP solution for linux?

I'm looking for a DLP (Data Leak Prevention) solution for linux environments. I know OpenDLP, but it's only a way to Prevent Clear-text file, and source codes from malicious access. There are lots of ...
5
votes
1answer
987 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 ...
4
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2answers
611 views

How can I use Skype with lxc?

Under Scientific-linux? https://en.wikipedia.org/wiki/LXC I just want to separate Skype, because I don't trust it. We are using it only to call/chat with people, no file transfers!
1
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3answers
234 views

Taking away a User's Read/Write/Execute Permission

So I have a user that is able to go in /etc and read files like httpd.conf. I would like to deny that user access to any critical locations such as /etc, /var and so on. What would be the best way ...
1
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1answer
22 views

Cluster Lock Manager without TCP/IP

I have 2 linux sharing same SAN disk LUN. There are many cluster files systems to manage lock/unlock. But all of them are using a seperate TCP/IP comminication. But I need a cluster lock manager ...
1
vote
1answer
24 views

user-level guide to maintaining Debian package update security? [closed]

Recently I listened to an interview with Kim Zetter (audio download here) on cybercrime/warfare, particularly Stuxnet and Flame. While listening to the discussion of how Flame exploited Windows ...
1
vote
1answer
21 views

How can I go about tracking down DNS queries?

I was looking at the dnsmasq logs on a router I run and noticed that there are requests to a particular url on a regular basis. This was happening while the only client connected to the network was my ...
4
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3answers
5k 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
1answer
22 views

rkhunter reports /sbin/ip has changed

I am using rkhunter 1.4.2 on CentOS 6.5. A message, in /var/log/rkhunter.log is Warning: The file properties have changed: [09:40:35] File: /sbin/ip [09:40:35] Current size: 247396 ...
1
vote
1answer
25 views

IP Camera with embedded Linux

I have purchased an IP Camera from Ebay (http://www.ebay.com/itm/151349669865). When I read the description of the camera, it said it has an embedded linux in it. I though that I will be able to ...
5
votes
2answers
48 views

Permissions depending on how you login: ssh/su/sudo

As user I have access to a remote linux machine where I can: sudo su - other_user Among other things, this allows me to add my own public key to authorized_keys for other_user, which effectively ...
5
votes
2answers
470 views

Why is 8 numbers considered a “strong” password?

Just curious as to why 8 numbers are accepted as a password in linux (CentOS if it matters) and not 8 characters on a non-dictionary word. It's 10 vs 26 per digit after all. (52 counting CaSe ...
2
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1answer
21 views

Parentals Controls? [closed]

How do we implement parental controls? We have a customer with multiple retail locations and one computer at each. They switched to Ubuntu to lock down the computers, but many of the employees are ...
0
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0answers
23 views

How do I force a command to be run on local login?

I was wondering how do I force a command on login of a linux system? (debian 7). This is for a 2FA authentication command. I am asking for a local login.. not ssh.
28
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5answers
2k views

Does /usr/sbin/nologin as a login shell serve a security purpose?

In my /etc/passwd file, I can see that the www-data user used by Apache, as well as all sorts of system users, have either /usr/sbin/nologin or /bin/false as their login shell. For example, here is a ...
2
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1answer
20 views

Security of capabilities vs setuid (LD_PRELOAD, etc)

I know that if a process is run setuid that it's protected against various things that could subvert the process, like LD_PRELOAD and ptrace (debugging). But I haven't been able to find anything on ...
2
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2answers
91 views

How to disallow file modification time change for non root users

I don't want anybody to create a file then change the creation date to backward date(For example using touch or system call). In my Ubuntu hosting account I'm getting many hacked php code getting ...
3
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1answer
45 views

Scan ~/Downloads on new file creation

I want all new files added to ~/Downloads (and sub-folders) to be scanned with clamscan. When using Firefox on other OSes/Machines I've noticed that downloaded files sometimes get automatically ...
5
votes
1answer
42 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 ...
1
vote
1answer
446 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 ...
0
votes
1answer
122 views

Is my linux mint box vulnerable to Shell-Shock attacks? How might I remedy that? [closed]

Is it safe to use Linux Mint now, with ShellShock existing? If not, what can I do to use Mint safely?
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2answers
33 views

Enabling SELinux on RHEL

I am using RHEL 6.5 and I need to enable SELinux. I have tried following commands, but it is of no help: $ setenforce 1 $ echo 1 > /selinux/enforce Note: I also tried editing ...
1
vote
1answer
711 views

Any better alternative to chroot on an OpenVZ VPS?

Are there any better alternative to chroot environment? I'm thinking about running nginx on a jailed environment. BTW, I'm on OpenVZ VPS, so modifying the Kernel is a no-no. (I think that prevents ...
8
votes
3answers
236 views

Trap: can't su as root, can't change group to wheel, ssh as root prohibited

Is this a trap? I made these steps in FreeBSD 10: 1) ssh as root prohibited 2) logged as user 3) su as root 4) as root chsh changed name of user "user" to "luser" 5) exit from ...
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1answer
31 views

Which Linux should I chose for penetration testing and networking [closed]

I am fairly new to networking and penetration testing, however, I'm really interested in the field and would like to know which distribution of Linux would be best to work with for security ...
1
vote
1answer
846 views

SSL handshake failure with Shibboleth [closed]

I am using Shibboleth for single user authentication and it needs a ssl configuration which facilitates the user authentication process. Before it was working fine but now I am facing a SSL handshake ...
2
votes
2answers
46 views

Secure Remote Backups Using Duplicity

The recent take-down of codespaces got me thinking about off-site backup processes (which I currently perform manually with password entry). I have been reading tutorials showing how to automate ...
2
votes
1answer
37 views

Remove ex-admin user account and grant privileges / permissions / ownership to another

I would like to find the simplest way to remove the old system admin's user and group from a Gentoo server and put them all under my name instead. He no longer works here and it would appear that a ...
8
votes
2answers
13k 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 ...
14
votes
6answers
5k views

Can root/superuser read my read-protected files?

On shared unix hosting, if I have a file sensitive-data.txt and I issue: chmod 600 sensitive-data.txt Can root user still read my file? Specifically I'm wondering if it's safe to store my password ...
3
votes
2answers
39 views

Lock system after awake suspend (incl. forced-shutdowns system after countdown)?

For speed and convenience I do not shutdown my system when I am only gone some minutes, but do a pm-suspend! When the system "unsuspends"/resumes I would like that there is a (screen)lock (on X and ...
0
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0answers
18 views

Is there a solution for scanning webserver files for malicious code?

I have seen several times people move code into web servers now that had malicious code embedded into their HTML, php and other documents. These then get served up from the new server until they are ...
0
votes
3answers
50 views

last command only shows few days worth of logins

I often use thelast command to check my systems for unauthorized logins, this command: last -Fd gives me the logins where I have remote logins showing with ip. From man last: -F Print full ...
0
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2answers
35 views

If I install malicious software what may it do? [closed]

If I software in a deb file and I do sudo dpkg -i file.deb will it execute code from the package and possibly wreck my system? If I log in as testuser and execute the software (simply thebinary on ...
1
vote
0answers
33 views

Establish IPSEC Tunnel between two Ubuntu 12.04 PCs over LAN

I have two ubuntu 12.04 32 Bit PCs between which I want IPSec Tunnel to be setup. I have setup ipsec in both systems and ipsec verify runs fine on both. Since I have no prior experience of openswan, I ...
8
votes
1answer
813 views

What makes systemd-nspawn still “unsuitable for secure container setups”?

This is stated in the man page for systemd-nspawn Note that even though these security precautions are taken systemd-nspawn is not suitable for secure container setups. Many of the security ...
90
votes
2answers
16k views

When was the shellshock (CVE-2014-6271/7169) bug introduced, and what is the patch that fully fixes it?

Some context about the bug: CVE-2014-6271 Bash supports exporting not just shell variables, but also shell functions to other bash instances, via the process environment to (indirect) child ...
2
votes
1answer
26 views

Is revealing DBUS_SESSION_BUS_ADDRESS variable a vulnerability?

I found this instructions: Using notify-send with cron Revealing the content of your DBUS_SESSION_BUS_ADDRESS like in this answer gives access to every user logged in to your session: #!/bin/sh ...
11
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8answers
4k views
1
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1answer
38 views

Latest libxml2 port to RHEL4

I am currently installing ModSecurity on our development servers and the problem that I am running into with the latest version is that we are utilizing RHEL 4 on our servers. They have no intention ...
6
votes
2answers
3k views

rkhunter warns me about root.rules

I run : :~$ sudo rkhunter --checkall --report-warnings-only One of the warnings I've got : Warning: Suspicious file types found in /dev: /dev/.udev/rules.d/root.rules: ASCII text and ...
5
votes
1answer
235 views

How can I find a Ubuntu package to use with Amazon EC2?

I'm looking to set up a new server on Amazon's EC2 and I wanted to use Ubuntu 11.04 is it is fairly new but not too new. I previously used 10.10 which I think is also very stable and time-tested. My ...