Securing Linux systems and applications; understanding Linux security features.

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DNS spoofing of linux distribution repositories

Question(s) Is it possible to "redirect" linux-update-repos via DNS spoofing (e.g. DNS cache poisoning) to a malicious website, so that harmful software (updates) will be installed, when running the ...
0
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1answer
27 views

VPS Privacy: OpenVZ vs KVM vs Xen

Considering OpenVZ, KVM and Xen: Which VM technology is the most difficult for the host's administrators to access given an encrypted root partition? Can I have a reasonable expectation that rogue ...
0
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2answers
31 views

How exactly does this Flash malware function on Ubuntu?

In this video, an experienced Ubuntu user manages to infect his system with some sort of malware. This is the first example I've ever seen of truly successful malware in the wild aside from privilege ...
0
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1answer
36 views

Ubuntu 12.04 server attacked using Wordpress vulnerability (plugin?) [duplicate]

Env Rackspace cloud server Wordpress 3.9.1 Ubuntu 12.04 Linux web.mydomain.com 3.2.0-67-virtual #101-Ubuntu SMP Tue Jul 15 17:58:37 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux History These may ...
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3answers
1k views

Can Windows malware harm a Linux computer when it's executed with Wine?

I am an (Ubuntu) Linux user. Sometimes, I have to use Wine for running Windows executables. I would like to know if Windows malware (virus, trojan, worm,...), i.e. malware that was not intended to ...
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3answers
121 views

Help me catch someone red handed on our server.

I first tried to log in this morning and our password was changed on our ubuntu server. I contacted our server support and they told me that I had just been fat fingering the password. I thought it ...
1
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1answer
52 views

Running an Open Server (contents are visible)

I'm considering the possibility of running an Open Server, as I would call it, that is, a server where as much of its contents are publicly visible as possible. I would like to give read access to ...
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0answers
20 views

Why isn't auditd logging file deletes? [migrated]

I have auditd installed on 64-bit Ubuntu 12.04 to track down some unexpected deletes (nice discussion of auditd). This is my rule (tagging deletes with the deletes keyword): -a exit,always -F ...
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1answer
53 views

What Linux software can I use to explore entropy of a file?

I've heard of tools that could be used to graph entropy of a file. Is there a graphical Linux program that I could use for this job that would let me conveniently explore which blocks of a file have ...
2
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3answers
67 views

Is there any way to block LD_PRELOAD and LD_LIBRARY_PATH on Linux?

Preferably with a vanilla Linux kernel i.e. not using SELinux or GrSecurity? Lately there has been a case of in-the-wild UNIX server malware: ...
2
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1answer
94 views

Is it safe to disable connection tracking in iptables?

While reading about NOTRACK target of raw table in iptables, I encountered an article suggesting that for certain traffic you could (or even should) disable connection tracking. The two examples were: ...
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1answer
64 views

Kali linux how to use and learn? [closed]

i have installed kali linux. i previously installed back track 5 r3. but i dnt knw how to use it? so i uninstalled. what are the main differences between kali and back track? does a lan wire with ...
2
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2answers
87 views

the dangers of internet forums - what is FUD, what is not

I just visited a forum and a member knew what OS I was running without me saying anything (a not TOO common distro of linux). Now I'm not sure how he exactly he might have done it, or what information ...
2
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1answer
29 views

What is a secure mechanism for wireless communication between Android and Ubuntu?

I have come across a few Android apps that provide various features for communicating with a desktop machine (sending text or typing in one direction or another, controlling the desktop pointer with ...
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4answers
2k views

Should I get an antivirus for Ubuntu?

Considering the recent thread regarding anti-virus for the Mac I wonder how many of the arguments put forth are relevant today to Linux systems, specifically Ubuntu. There are no known Ubuntu ...
0
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1answer
39 views

Wireshark: could “Follow TCP Stream” yield an empty window? or is it a bug?

I am capturing a pop3 netcat connection (port 110) using Wireshark, on Debian linux (Kali). After filtering packets with (tcp.port eq 110) I get few packets but once I R.Click on any and click "Follow ...
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2answers
649 views

What Ubuntu packages are still affected by gnutls bug CVE-2014-0092?

Right now the internet is abuzz with news about a severe breach in GnuTLS. An update to the relevant GnuTLS packages has already been released. But I am worried whether some packages might have had ...
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6answers
3k views

How can I protect my computer from my potentially malicious colleagues?

So, I work in this small company (10 people) where we do stuff in programming, for various platforms. I started recently working there (2 months) right after I graduated. My work is not exactly ...
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2answers
46 views

How to hide or obfuscate the type of OS?

I get the OS type of a remote host by: connecting to an open port (telnet <host> 22); using Nmap (nmap -A <host>). What are techniques and how to hide or change the information about ...
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0answers
15 views

How do I have automatic encrypted backups? [migrated]

I have a jailbroken iPhone, 2 Laptops, and another server. I will set up these devices to backup files to a main backup server I have but I'm wondering how I can have this done automatically while ...
0
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1answer
70 views

In return to libc how do you know the address of system() in a remote machine?

I have the following scienarion: a vulnerable program running in a server and can be accessed using netcat I have a copy of that program locally and I can exploit it locally using ROP: ./vuln ...
2
votes
1answer
116 views

Current industry standard key management solution for web app on linux host

The scenario: Data is sent to an application server and you want to selectively encrypt some data before sending it to a DB server for storage. All servers run some linux distro. This is a relatively ...
2
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2answers
71 views

PHP shellcode inside /tmp. Is the server compromised?

I have a Debian 7 VPS that runs Nginx, PHP5-FPM and MariaDB. This server runs a couple of WordPress installations, phpMyAdmin and Roundcube Webmail. One is my personal blog running WP 3.9.1 and ...
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1answer
172 views

how to protect my linux pc from wifi sniffing

I have a wifi shared connection with other flatmates and I'd like to know how can I protect my Debian pc from being sniffed. Should I use a wifi anti sniffer to detect if any wifi card is in ...
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0answers
18 views

Should my server ever need to directly communicate with the NAT gateway? [migrated]

What I mean by ``directly communicate'' Does it ever need to receive packets with the gateway's IP address as the source IP address, or send packets with the gateway's IP address as the destination ...
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4answers
57 views

Can a virus on the host affect the VM guest [duplicate]

let me explain my problem. The wifi on my macbook suddenly stopped working so tried to use my usb wifi adapter on a linux VM. But the funny thing is that nothing works on the guest vm either... Well ...
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2answers
79 views

Storing SSH private keys on an Android device

(I'm not sure if this better belongs on unix.se or android.se, but since it's primarily security-related, I'm asking it here) I use my Android device to access servers for quick on-the-go ...
2
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0answers
43 views

Can a malicious user do any harm using /dev/kvm?

I'd like to know if giving access to Intel version of /dev/kvm on Linux to a user that just wants to spawn VMs gives him any extra privileges. That is, are her VMs subject to process scheduling just ...
2
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1answer
19 views

How do I customize /proc permissions?

So that: Only process owners, and root, can access information about their processes, Or, at the very least, cmdline permissions are only readable by root, and My system (CentOS 6.x) still runs ...
5
votes
4answers
1k views

What are the most common files to check with File integrity monitoring software?

I have a file integrity monitoring suite and in it I have to select specific files and folders for it to monitor. There are some obvious services that I want monitored like our web-server. Is there a ...
0
votes
2answers
102 views

Store a file on a harddisk without root having access to it

Is there a way to store a file on a disk as a user so that even the root user has no access to it? I tried EncFS but that is no solution because the root user can switch to every user, so he/she can ...
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1answer
47 views

How should privileged accounts be secured in both Linux and Windows?

I have recently started work in application security at a mid-sized firm, having transitioned away from 5+ years in security consulting (pentesting, etc). One of the biggest challenges I see here from ...
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4answers
2k views

environment variable accessibility in Linux

Perhaps this is a trivial question, but how accessible are environment variables in Linux between different users? e.g. if Alice executes export FAVORITE_FOOD=`cat /home/alice/fav_food.txt` Can ...
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2answers
111 views

Clarifying MITM attacks and Digital Certificate requirement

We are running a Portal application for our client with Payment Gateway integrated. Payment gateway uses SSL as it is suppose to be . The concern for me is that our Portal application does not use ...
0
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1answer
28 views

benefits of xinetd for a web server

What are the pros and cons of using xinetd for a web server running on a VPS. Assume the following measures have already been taken to secure the system: system hardening, latest updates, minimal ...
1
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1answer
269 views

Installing Joomla with nobody:nobody user/group (CentOS/cPanel)

If you are installing Joomla via cPanel's File Manager to your mywebsite.com (user mywebsite) account, you will upload the package to your server and extract the archive. All files will have the user ...
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2answers
36 views

How can we know which debian package correct which CVE

We can found on the debian's website CPE/Aliases List, CVE List related to packages. But I can't figure out where can we know which patch of packages correct which vulnerabilities ? For instance : ...
4
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2answers
140 views

You've just acquired a newly created CentOS server, what should you do to secure it?

I've just acquired a new CentOS server, which will be hosting a Ruby on rails application, it is public facing. What should I do to secure this server?
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1answer
59 views

Proccess to exploit an OS vulnerability [closed]

What are the steps to use an exploit on an OS vulnerability? I tried the popular ms08-067 on an XP machine, following a guide found on the internet, discovering Metasploit etc., but I can't figure ...
15
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7answers
981 views

Defence Against Keyboard Keylogger

I am wondering whether there is a way to defend against USB Keyboard Keylogger (obviously other than physically checking the keyboard every time after leaving my computer unattended). These days, ...
6
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3answers
152 views

How to sandbox Iceweasel (Firefox) on Debian? [closed]

Are there any tools for sandboxing Iceweasel (Firefox) on Debian systems? I'm mostly interested in tools distributed by Debian. (An equally trustworthy source would be second best.) (I suppose that ...
1
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2answers
59 views

What's there to harden for a home Unix-box behind Comcast cable modem?

I'm learning that much of the security advice I come across under the "hardening" heading simply does not apply to a single-user home desktop box sitting in a private wireless IPv4 LAN behind a ...
2
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2answers
217 views

I've found security vulnerability in current linux distribution. What next?

I've installed ubuntu server 12.04 on VM two weeks ago. I've created regular snapshots. XXX time ago I've noticed unusual activity and I've found that a backdoor was installed into my server. One of ...
47
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7answers
5k views

Can “cat-ing” a file be a potential security risk?

I often use cat on the console to view the contents of files, and every now and then I accidentally cat a binary file which basically produces gibberish and system beeps. However today I've ...
3
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3answers
104 views

Protect partition from formatting

How can i protect my Linux and Windows partitions from being wiped,from a windows installation CD,with password?
2
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2answers
30 views

Is there a website or other resource that lists operating systems/platforms and the included root certificates?

I need to choose a certification authority (CA), to get a certificate, but I noticed that there are several of these only present in some operating systems/platforms like windows. I need to choose one ...
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2answers
96 views

Open Source OS - code you see vs code you get

In this question I will use the example of Linux OS, but I am also interested in general situation. Linux OS distributions are famous for being open source and thus rather secure. But how can you be ...
2
votes
3answers
80 views

How to setup a dedicated home machine (Linux) for secure transactions?

I would like to set up a computer at home (preferably running Debian, or some other flavor of Linux) to be used only for secure financial transactions. The idea is that, by strictly limiting what is ...
3
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2answers
171 views

How do shared hosts protect different sites?

I host all my websites from a single VPN, and am about to sell some limited space of my Linode to a friend to host their new blog. It'll simply be another entry in Apache, and then a dedicated folder ...
8
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4answers
2k views

How secure is NOPASSWD in passwordless sudo mode?

On all our boxes we have ssh access via keys. All keys are password protected. At this moment the sudo mode is not passwordless. Because the number of VMs are growing in our setup, we investigate the ...