Securing Linux systems and applications; understanding Linux security features.

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At OpenSSH ssh server side key files has 0 data. I would like to know the reason for it

I am using the Monta Vista Linux. In this recently i have observed the ssh keys files has 0 data due to which the keys were not generating and i am not able to login to machine via ssh because of key ...
2
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3answers
517 views

Malware getting root access via “sudo” and “sudo -s”

Actually, I'd like to ask 3 questions. But since they are very related, I'll ask them all here. I use Ubuntu 12.04.4. Situation 1: I use Terminator, in one of its terminals I launch sudo iotop ...
4
votes
1answer
159 views

Desktop Flickers Past Lock Screen

I'm using Fedora 22 with Gnome 3. I have a password set for my user account, so when my laptop awakens from sleep, I am presented with the lock screen and must enter my password before getting to my ...
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2answers
70 views

Are there any dangers in sharing ifconfig information publicly?

If I were to share my ifconfig information from Linux publicly, is there any possible danger associated with this action?
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1answer
819 views

How to use wordlist [closed]

I have downloaded a wordlist from https://crackstation.net/buy-crackstation-wordlist-password-cracking-dictionary.htm The size of the wordlist is 4.2 GiB (compressed) or 15 GiB (uncompressed) The ...
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5answers
1k views

How secure is it to keep the salt with the password hash? [duplicate]

In Linux we have the salt just next to the password hash in the /etc/shadows file. I always hear that salt value prevents hashed passwords from being cracked by brute force methods. But if somehow we ...
3
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3answers
677 views

Error message in Apache logs shows /bin/bash and wget

I am wondering if my server is compromised or not I just looked at my log and seen the following line in there [Thu May 14 09:10:42.587255 2015] [autoindex:error] [pid 3422] [client ...
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2answers
416 views

How to make data in hard disk unrecoverable on linux [duplicate]

I need to wipe completely the data on my hard disk so it's unrecoverable. I'm actually using Linux, i have seen this command on the web, but I don't know if its secure. shred -zvn 35 /dev/sdb
5
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1answer
146 views

Video site requests Adblocker to be shut off, next day I have 3 “weird” bookmarks

I was on a site trying to view a video and the site requested that I turn off my adblocker to view the video. So I did and then the next day I noticed that I had 3 "weird" bookmarks in my bookmark ...
0
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1answer
99 views

When can the exploit for CVE: 2006-7098 be used?

I'm studying the vulnerabilities of an old version of Apache, the 1.3.34. And I don't quite understand in what exact situation the CVE 2006-7098 vulnerability can be exploited. The README included in ...
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0answers
326 views

TPM Command Line Tools

I am trying to create a key storage hierarchy on TPM (Trusted Platform Module) on Linux (CentOS 6.4). The most commonly recommended TPM tool suite on Linux is TrouSerS. However, the command line suite ...
0
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2answers
177 views

PCI-DSS, what is the best distro? [closed]

What is the best distro of Linux to get PCI-DSS compliant? I am using Debian 8 because I think Debian is one of the most stable versions, but it seems not to be enough, I am struggling with a lot of ...
3
votes
1answer
299 views

How to check whether my USB flash drive was infected by the BadUSB

After failing to check whether my USB stick firmware can be rewritten AT ALL, I want find out, whether it WAS rewritten when I sticked it in another computer. In particular the question is: how to ...
2
votes
2answers
50 views

Which software RNG for linux?

A headless server can suffer from a lack of entropy, which is a problem given that encryption needs random numbers. In the absence of a hardware random number generator (RNG) the numbers must be ...
2
votes
1answer
63 views

Security implication of non-free drivers

I was wondering what the security implications are of using non-free drivers on a linux laptop. Especially for graphics and wifi.
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3answers
151 views

How do I ensure that my Ubuntu download has not been tampered with?

I am downloading Ubuntu Linux, and would like to make sure that my download has not been tampered with. Ubuntu has a GPG key, which I could use to make sure that the download is valid -- but how do I ...
0
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2answers
566 views

Can I VPN a phone's connection to my home network, and then apply my home firewall to my phones network connections?

I have a decent firewall/router at home, and I was wondering whether it would be possible to use my home firewall for the connections that my phone makes, even when I'm not at home. It would mean ...
8
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1answer
1k views

Why is plain dm-crypt only recommended for experts?

I am curious about the following claim from the Cryptsetup FAQ: 2.4 What is the difference between "plain" and LUKS format? First, unless you happen to understand the cryptographic background ...
5
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2answers
91 views

SSH: Security of Pubkey Authentication vs Password

Why is Pubkey Authentication considered more secure than a password, and does this apply to my situation (described in more detail below)? I'm a scientist (no formal IT training), but I built and ...
3
votes
1answer
118 views

Is a newly installed server with no services running (but connected to the web) at risk?

A new server has just been installed but literally has nothing else running on it, no services setup to SSH in or anything yet (it's a Linux server). However, it is hooked up to the web so I can ...
2
votes
0answers
121 views

chroot ssh users [closed]

I am using CentOS 7. I need to give shell access to ssh users but restrict them in a jail. I have used jailkit to set up the jail. I have copied all necessary libraries, binaries that are needed for ...
1
vote
1answer
58 views

Linux Kernel module signing

If the linux kernel is compiled to check for kernel modules signing, it checks the validity of the public key (X.509) w.r.t the current system time. For the first time the system is booting up, it ...
4
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1answer
161 views

How can I delete a password and lock the account in one step?

I have a minimal server install on a remote machine with a root password set to a temporary, but chosen, value. I have added a separate administrator user. This user has an authorized key for SSH, no ...
5
votes
1answer
2k views

ARP-poisoning on wireless network - no packets

I've started working with ettercap and ARP-poisoning; however, I've sumbled upon some problems. I've executed the following command: ettercap -i wlan0 -w log -T -M arp:remote /192.168.1.254/ ...
4
votes
1answer
495 views

/dev/random in EC2 cloud

is /dev/random any good in AWS EC2 for use in making a shared key that will be passed over a secure channel? i am concerned that a launched instance would have not much entropy to begin with. what ...
0
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0answers
117 views

Linux: Chinese Unionpay plugin, Ubuntu 64-bit - Spamware / Trojan?

China / Linux / Bank / Trojan / Backdoor / Executables Hey guys. I've got an account with a Chinese bank (I live here), and in the process of setting up an online account for the Chinese version of ...
22
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7answers
5k views

Convenient cross-platform help on checking secure hashes like SHA-256

It is often helpful to be able to obtain a good cryptographic checksum of a file, e.g. the SHA-256 hash. This can be used to verify file integrity, so long as you have a reliable source for the hash. ...
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2answers
135 views

How hard would it be to scramble crypto keys in memory on command?

I'm looking for a way locate a set of keys in memory on command. Use case would be cold boot attack prevention: a trigger on rack open, scramble the keys in memory followed by shutdown in full disk ...
0
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1answer
393 views

Can I use a VPN to disguise internet traffic at work? [closed]

I have seen this question asked before; I want to know if I can use a VPN to disguise my internet traffic so my employer can't see what websites I'm visiting while at work. However, unlike most ...
2
votes
1answer
780 views

GnuTLS ServerHello exploit (CVE-2014-3466) - how to verify?

So pretty much all of the GNUTLS world is worrying about CVE-2014-3466. I checked my Kali and it responds with this - # apt-cache rdepends libgnutls26 | grep -v lib Reverse Depends: ...
2
votes
1answer
523 views

Are there any security implications in creating an SSH key for the root user?

I've written an install script on a server to quickly set up new sites in the /srv directory. It needs to do a git clone, and has to be run via sudo in order to have the permissions to do all the ...
0
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1answer
364 views

Moving /tmp to an encrypted tmpfs

BLUF: I'm using an SSD on my system, so my primary reason to use tmpfs to increase the life of my drive by moving high read/write files to volatile memory. But from a security point of view, I'd also ...
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3answers
225 views

How bad is it to *not* reboot a server after kernel updates?

I’m administrating a few Debian Linux server, and install package updates when apticron notifies me of them. Occasionally I see updates to linux-image-[something] packages, but don’t bother to reboot ...
78
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9answers
16k views

Hardening Linux Server

We have already had questions on here about Hardening Apache, Hardening PHP and Securing SSH. To continue this trend I am interested in what steps people take to harden Linux servers. As in what ...
0
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0answers
52 views

Is it possible to lock guest VMs (or processes) to sticks of physical RAM to prevent row hammer attacks?

I was wondering if it is possible through some means to isolate processes (or preferably guest VMs) to physical sticks of RAM. This would be to prevent row hammer like attacks from using physical ...
1
vote
1answer
280 views

Securing a VPS network with a VPN and a DMZ

I've got several VPS boxes (Digital Ocean boxes w/Ubuntu) that I would like to lock down from the outside world. I want to have several private boxes (web servers, db servers, puppet/master boxes ...
0
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1answer
114 views

OWASP + Atomic ModSecurity Rulesets - Too much?

Looking to implement some additional mod_sec rulesets on our server. OWASP and Atomic keep coming up as the best of the best. Would it be wise to implement both? Or, would one or the other be ...
2
votes
1answer
100 views

How to verify installed packages [closed]

On Linux (Debian x64) I recently installed some software with: apt-get install the_package_name APT told me some packages couldn't be authenticated but I ignored the warning and installed anyway. ...
33
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4answers
31k views

How do you know your server has been compromised?

I recently helped a client who had their server hacked. The hackers added some PHP code into the header of the homepage redirecting the user to a porn website — but only if they came from Google. This ...
7
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2answers
810 views

Linux kernel entropy - does it matter to /dev/urandom and what is a minimum?

This question had been asked several times, but still something's not clearly understood from other answers I have a few servers running with a custom built linux kernel (minimal driver modules etc), ...
5
votes
2answers
698 views

IPsec on multicast

I am trying to implement IPSec for multicast communication, I tried strongSwan for setting up IPSec for unicast but it doesn't support any standard for multicast ipsec as listed here ...
5
votes
2answers
159 views

Linux random number compliance

Not sure if this is the right forum, and I am pretty sure that his must have been answered before (I searched a lot but I haven't found a definitive answer). Do the Linux random number generators ...
1
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0answers
260 views

Snort alerts analysis (web interface) [closed]

I have a question about Snort (or maybe any other IDS/IPS, any working solutions would be ok). The goal is to set up some web interface providing a way to view the whole TCP stream packets of each ...
23
votes
3answers
3k views

Linux-based Turla trojan

There are several articles describing the newly discovered Linux-based Turla trojan. But basically, all these articles repeat the same, very limited, information. Can anybody provide more details, ...
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votes
1answer
90 views

Official proof (document) that Linux is safer and faster than Windows [closed]

I work for the Mexican government, and even though everyone involved in Linux knows that it is safer and runs faster in most instances, I have not found an official document or authority that I can ...
1
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2answers
770 views

Setting up a security lab, looking for a little guidance [duplicate]

I'm new here. Over the past couple of years I've had a growing interest in the security aspects of IT/CS. Recently, I've started setting up a lab for myself based on a kali/win7 dualboot and I've ...
11
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4answers
4k views

How to detect Meterpreter and similar malware?

Is it possible to find Meterpreter or similar malware which doesn't modify the hard disk but is only stored in RAM? Most common anti-rootkit software like rkhunter and chkrootkit don't find it.
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1answer
56 views

Linux Updates to Shellshock

My question is about the community response to Shellshock. What improvements were made in either the Linux development cycle or in the recommendation to its users to prevent something like ...
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votes
2answers
77 views

Server Files Got Exposed, What Security Steps Should I Take? [duplicate]

so I made a script that would accept a GET request through a script on my page download the url in the GET and then echo the response. Sort of like an in browser proxy. Basically someone found out ...
2
votes
1answer
360 views

exploiting Heap Overflow in gdb segfaults

I have been trying to exploit the heap overflow vulnerability for the program below, I am running Linux 14.04. #include <stdio.h> #include <string.h> #include <stdlib.h> int n = 5; ...