Securing Linux systems and applications; understanding Linux security features.

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12
votes
3answers
1k views

What security measures should be taken when running a Linux web server out of our office?

I am interested in running our company's web server from our local office. The office makes use of file sharing and NAS devices among other common office protocols. The worst case scenarios I've ...
14
votes
3answers
2k views

Breaching security of a notebook with full disc encryption when screen is locked

I am using full disc encryption on my portable computer (running Ubuntu). The setup requires me to enter a password during the boot sequence to access fully encrypted hard drive. There is no ...
2
votes
2answers
87 views

Prevent Plain-Text Passwords Output by a Script From Being Accessible in the Future

Let's say I have a Bash script that generates a password, creates a new user with that password, and then tells me what the password is: # Generate a password and set it to $PASSWORD PASSWORD=$(tr ...
4
votes
1answer
98 views

LUKS TPM disk encryption attacks

Is it possible, or are there any known attacks, to get the encryption key for disk encryption tpm-luks? (Linux LUKS using encryption key stored in TPM) I know that there are attacks like cold boot ...
-4
votes
1answer
111 views

Hacking into a simple linux server [closed]

I'm very new to hacking in general so I wanted to learn more. I have an exercise, whereby we have a raspberry pi with a simple website on it and we have to get a file and the stored gpg private key on ...
0
votes
1answer
82 views

How to detect arp spoofing using iptable? [closed]

How can I set iptables to detect arp spoofing on linux?
1
vote
2answers
76 views

Will a wildcard SSL work properly for an A record subdomain pointing to another domain/website?

Client has wildcard SSL for his domain/subdomains. The application we are building is on one of our linux servers using one of our IP addresses and is contained within an account named ...
4
votes
4answers
165 views

Should I format storage after buying it?

I've just bought a new (unused) external HDD. Should I format it or is it save to use it directly? Did it already happen that a device was infected before the first customer use? Will formatting ...
2
votes
1answer
59 views

Properly solving IP leaking from WebRTC and other apps with STUN when using a VPN

This is really a follow-up question from this: Stun scripts/webRTC IP leaks I'm connecting to a VPN using a virtual adapter, which has a default routing rule so all traffic goes through it. I still ...
1
vote
0answers
124 views

Converting Metasploit module to standalone Python script [closed]

How easy is to convert Ruby code to Python code and to change Metasploit module into standalone Python script for Linux?
1
vote
1answer
83 views

Is it possible to disable `ypcat passwd`

We have an old NIS setup which, at geological speed, is being replaced by a Kerberos one. In the meantime, all the (non-root) users can simply type ypcat passwd and get the hashes of all the users' ...
0
votes
2answers
65 views

Testing shellshock with PHP

I have been trying to test shellshock vulnerability on PHP similar to this answer. I am running Apache server with PHP running as mod_php. The PHP version is 5.3.10. I have a phpfile (phptest.php): ...
1
vote
2answers
78 views

$chsh command security with Set-UID

Why does $chsh have to be a Set-UID command? What are the vulnerabilities of a normal user changing his/her own shell from perhaps bash to zsh? Any help would be greatly appreciated!
-1
votes
1answer
90 views

Understanding HTTP response from Linux Server

I am working through a question that involves someone using a vulnerability in a Linux server in order to gain access to it. The first part of the question states In monitoring the network activity ...
-1
votes
2answers
54 views

Prevent fake gateway device attached to PC's network card

Office. Several PCs with Linux. Internet is limited on gateway level, so nobody could do POST-requests over HTTP. We prepared several measures to prevent data leakage on infrastructure level, but ...
7
votes
2answers
173 views

Prevent ARP spoofing with dynamic static entry on Linux

ARP spoofing detection/prevention seems to be quite popular here. With other techniques like port stealing aside, I'm wondering if the following could work to prevent it: Whenever my Linux ...
6
votes
1answer
123 views

Automatically enumerate missing patches on penetration test

Nessus, when running a credentialed scan can check patch levels and return vulnerabilities when a package is one that hasn't been updated to the latest, non-vulnerable version. What is a good way of ...
1
vote
1answer
68 views

Strange entry in Apache's ports.conf

I am not sure if this may indicate a compromised server or if I'm just being paranoid. While fiddling around with Apache and Webmin on a new Ubuntu 14.04 virtual server (as well as DNS records for ...
4
votes
3answers
69 views

How risky is to use non-free wireless network driver?

Intel wireless network adapter in my computer requires a non-free driver to work. I don't want to install non-free software to my debian system. However it is a notebook and without wireless network ...
2
votes
0answers
29 views

Is an unprivileged LXC where the host user itself is mapped to 0 less secure of one where one of its subids is mapped to 0, and why?

Instead of creating "common" LXC unprivileged containers where all the users are mapped to (unprivileged) subuid/gid of my host user, I'm considering a mapping where my host user itself will be mapped ...
7
votes
2answers
2k views

I don't recognise my DNS server's address: does this mean I am compromised?

I'm using the Ubuntu GNOME Linux distribution as my desktop. Recently, it became impossible for me to connect to the Internet with it. When I checked its network settings, I saw that the DNS address ...
1
vote
0answers
30 views

iptable ip_conntrack_max testing

I was trying to understand how ip_conntrack_max works so i have created two VM and set ip_conntrack_max to 10000 I used hping to open 10000 udp connection on VM using following command hping --udp ...
1
vote
2answers
267 views

TSource Engine Query DDoS attack

My gaming machine is under DDoS attack and when I used Wireshark I found the following string "TSource Engine Query" in all UDP packets coming from random IP's. I found using Google that some gaming ...
3
votes
3answers
170 views

How to choose a linux for learning? [closed]

I am beginner in Security. My first assignment is about "Linux firewall using IPTABLES" . I know about Ubuntu, backtrack and kali Linux. How to choose a Linux distribution to learn about security?
1
vote
1answer
138 views

Cannot connect using ECDH-RSA-AES256-SHA

I try to establish an SSL connection using the ECDH-RSA-AES256-SHA cipher using OpenSSL, but it fails saying "no shared cipher": On the server, I run: $ openssl s_server -cert selfsigned_cert.pem ...
1
vote
1answer
206 views

Security research on Operating system security measures, where to start?

I am researching on operating system security, And I don't know where to look for more information on this. I could find the following sources, but I need more guidance. Sources: Microkernel ...
5
votes
1answer
137 views

My dlink router seems to be compromised

By chance I read today about this huge vulnerability regarding my router Dlink DIR-600. ( http://www.s3cur1ty.de/m1adv2013-003 ) Just out of curiosity about what I would find, I tried to send some ...
4
votes
2answers
690 views

Malware (adware?) infection on linux

Recently I've get stuck with a malware(adware/virus ?) which I can't remove. here is the condition: I'm using Linux (Archlinux), it's uptodate and I don't install any packages outside standard repos ...
1
vote
1answer
42 views

Sensitive information to exclude from Linux server before providing complete backup to vendor for troubleshooting [closed]

A vendor requested a complete backup of a server for troubleshooting a bare metal restore issue, but they said we are free to exclude any sensitive data. I’m thinking I’ll exclude: /etc/shadow ...
-1
votes
1answer
289 views

SQLMAP --OS-SHELL error [closed]

root@kali:~# sqlmap -u http://www.a***********.com/info.php?id=2 --os-shell _ _ _| |_____ _ {1.0-dev-nongit-20150907} | -| . | | | .'| . | || |||||,| | || |_| ...
8
votes
7answers
305 views

is it possible to keep something invisible to the server admin?

Let's considering the following scenario, an investment firm runs a computer cluster(using red hat as os), some computation which involves some company's trading secret will run on it, there is a SA ...
3
votes
2answers
278 views

Does CVE-2015-5352 work if there is no active X-Server?

My security program shows that one of my servers is vulnerable to CVE-2015-5352. If X-Server is not running (not even installed) is the system really penetrable by that vulnerability?
-4
votes
3answers
94 views

Reverse Engineer and Exploits researching [closed]

Can some one give me a start point for finding exploits in software and reverse engineering? I need some kind of a book or a site... I have background with programming with high and low level such ...
1
vote
2answers
74 views

Public Key Pinning and subdomains

Shortly I have intend to install new webserver and I'd like to secure users a little bit more. I already have domain, (virtual) server and everything else that matters when configuring a server. ...
-2
votes
2answers
179 views

Use of Nmap ssl/http md5 and SHA1 hashes

I have below stated result on of the system by map: 443/tcp open ssl/http Apache httpd 2.0.52 ((CentOS)) | http-methods: GET HEAD POST OPTIONS TRACE | Potentially risky methods: TRACE |_See ...
4
votes
2answers
72 views

Is it a good practice to use certificates as a mean of client identification in a cloud environment

My software system is running a cloud infrastructure where having Linux machines VPN into OpenVPN gateway is a setup requirement. Also, there may be cases when software on the aforementioned Linux ...
4
votes
3answers
4k views

Is Linux spying on its users? [closed]

If you install some kind of Linux distributions on your computer, is their a possibility that their owners may spy on you? For example, can Ubuntu, Kali or Arch linux send data to its owners on what ...
0
votes
0answers
23 views

Get data file off critical database host

Re-wording this question to hopefully be more understandable. Thanks for the feedback. We have a data warehouse which sits in our production environment. Our data engineers can get to the host via ...
6
votes
1answer
288 views

Are encryption keys wiped from RAM before hibernate, or how to do it (Luks and Truecrypt)

Using Linux, I have system and swap/hibernation partitions encrypted with LUKS, and data partitions encrypted with Truecrypt, and I am wondering when I put my laptop to hibernation if the encryption ...
-5
votes
1answer
90 views

Time-based password change [closed]

I have created this script and it runs great, but important questions remain. Is this script useful and secure? Does it have any possible problem or weakness? root@010010:/# ls -la ...
3
votes
1answer
238 views

Can BIOS firmware log keyboard input? If so, is there any way to detect and prevent it?

Recently I purchased a server board made by Lenovo with a "Intel Management Engine" inside BIOS. It is said that it is able to intercept and redirect keyboard input, even if an operating system is ...
3
votes
1answer
64 views

How use snort with local.rules in offline mode?

I'm using SecurityOnion distro and I would to run snort on my pcap files. Is there a way to specify just one rule? I couldn't understand whether local.rules is used. How can I show only the result ...
5
votes
2answers
226 views

How to secure a local socket?

I have made a service written in c that runs on the Android operating system as a core service. I have a few Android apps which communicate with this service via a socket connection (Java -> C). My ...
4
votes
1answer
379 views

What are the mitigating factors for CVE-2015-5364?

CVE-2015-5364 describes a UDP based DoS vulnerability in the Linux kernel that can be used to deny processing cycles to the host operating system and its applications. ...
12
votes
3answers
2k views

Are there ransomware infections of Ubuntu Linux in the wild?

Due to the recent media coverage of ransomware attacks several people for whom I've provided personal computer support in the past have expressed concerned. The majority of these people are running ...
7
votes
2answers
151 views

Why does Android use SELinux?

To restrict/sandbox processes Android uses SELinux. Why was that chosen and not the linux capabilities or cgroups+namespaces solution? After all the cgroups+namespaces is kind of home grown for them ...
0
votes
1answer
201 views

What is a Truecrypt alternative with deniable encryption for linux? [closed]

Preferably an alternative that is Free Liberating Open-Source Software/ FLOSS. I would have used Truecrypt, but it has been discontinued.
3
votes
2answers
197 views

How secure is loging into internet banking via an https library?

My bank does not have an API so I want my server to log in and check incoming payments to notify me if a client has paid or not. I would like the server to log in and scrape using Beautifulsoup and ...
2
votes
1answer
150 views

PPP over SSH - is this correct?

I see a lot of talk online about whipping up a VPN connection using PPP over SSH. This term confuses me, as SSH is an app tier protocol and PPP operates on the data-link layer. So, my question is: ...
105
votes
8answers
15k views

Are there technical differences which make Linux less vulnerable to virus than Windows?

What makes Linux so different than Windows in terms of anti-virus needs? My question is not if I should get an anti-virus for my Linux. I perfectly understand why an AV is important. I would like ...