Securing Linux systems and applications; understanding Linux security features.

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2
votes
3answers
139 views

Is it okay to only use username/password to secure an admin page for moderating a website?

Is there a standard practice to securing an admin page for an application written in angular and nodejs or just in general? The admin page would approve/ban users and moderate comments. Should it be ...
1
vote
1answer
50 views

NMAP Scan Returns Odd OS Detection [closed]

I am new to NMAP but I was using it to troubleshoot some issues I have been having. I ran a scan on a device and I know the device runs some sort of Linux or Ubuntu OS and I was attempting to figure ...
1
vote
1answer
88 views

Is End to End encryption possible for all servers across the whole infrastructure?

Running into a possible situation where a client I am working with is requesting that all data that leaves the servers should be encrypted and here, we are talking of hundreds of Linux servers ...
2
votes
1answer
369 views

How to measure the integrity of the OS (Linux)?

I am working on a project which requires Integrity measurement of OS (Linux). One way to do that is using IMA but I am not sure if it fits in the scenario below. The scenario of the project is some ...
4
votes
1answer
25 views

What security problems does copying .Xauthority to another user present?

If I want to use a GUI application with another user (example: webbrowser), I can copy the .Xauthority file to that given user's home then I can "su - user" and start the GUI app. Question: but what ...
4
votes
2answers
113 views

Is there a way to check for “hollow” processes, or malware hidden within “normal” processes

I recently came across an article on the The Verge, which centers around the concept of commercial malware production and how it's used around the world. The article introduced me to a number of ...
1
vote
2answers
143 views

How to change default cipher in GnuPG on both Linux and Windows?

How can I change the default symmetric cipher used by GnuPG from CAST5 to another? I'm using GPG4Win on Windows, but would also be interested in a solution for Linux.
2
votes
2answers
73 views

What are the security risks in leaving 'sudo' inside my production code?

I have a script that can only run successfully with root permissions But in development it's really hard to run with root permissions (in my development environment) so I add 'sudo' when ever it's ...
1
vote
2answers
565 views

Tails OS for Android and PC?

Can I use Tails OS on a USB-stick on both an Android tablet and a PC, or do I have to have two different versions? Would I have to go into the BIOS to make this work?
1
vote
1answer
81 views

Read SSL Certs with user process

I am running my own server, on which I have different services (Nginx etc.). All these (internet) services are / should be secured with SSL (offcialy signed). The key files / certificates are located ...
0
votes
1answer
63 views

php- is my code secured enough to protect from remote command execution when using shell_exec()?

I am using shell_exec function on the following variables to execute commands on the shell: fname (characters only) fpack(characters only) email (a valid email address) My code is: <?php ...
4
votes
1answer
103 views

Linux/ssh - Forensic question

In a Linux terminal, I made a ssh connection from A to B and I used commands to read some files stored in B. Then I disconnected and I closed the terminal. Is it possible to find on A, informations ...
0
votes
1answer
42 views

Are paravirtualized drivers a security risk?

Below is a copy of my answer that I gave in some other thread (Would running VMs inside of VMs be a more secure way to study viruses, etc?) about a topic of security of nested virtualization. I would ...
-4
votes
3answers
154 views

Can I do hacking using Windows OS? [closed]

I have searched the web a numerous times but haven't found an explicit answer to my question. I've studied (at school and on my own) computer networks for 2 years, doing active programming for 4 years ...
1
vote
2answers
100 views

How to test the php vulnerability CVE-2014-3515

How to test if I'm vulnerable regarding CVE-2014-3515? My vendor supplied me with a patch and verified that it installed however I would like to verify that I am no longer vulnerable. My vendor ...
5
votes
2answers
104 views

Four eyes authentication for command execution on Linux. (OS level) [closed]

I reached the end of the internet with no success, so now I turn to you guys. What I'm after is a way to implement four eyes principle on the OS level for certain commands in Linux. Example : The ...
33
votes
3answers
67k views

What is the difference between authorized_key and known_host file for SSH?

I am learning basics of SSH protocol. I am confused between the contents of the following 2 files: ~/.ssh/authorized_keys: Holds a list of authorized public keys for servers. When the client ...
1
vote
0answers
90 views

open ports on a netgear N-150 router; disable SPI firewall? [closed]

How do I open all ports? At least internally, for LAN traffic from 192.168.1.x to 192.168.1.x I want all ports open. Even if it creates a security problem. thufir@doge:~$ thufir@doge:~$ nmap -p ...
-1
votes
3answers
185 views

How to determine if someone is scanning my server?

How is possible to determine if someone make requests with tools for pentesting? Is there any linux command?
0
votes
0answers
79 views

Man in the middle attack, bridging wlan interface to virtual wired interface at0

I'm trying to execute a Man in the Middle attack on my mobile phone, I have two wireless cards, one inbuilt in the laptop, running AR9285 atheros drivers, the 2nd is an Alfa AWUS036NHA card with an ...
1
vote
2answers
125 views

Roommate Frequently Hacked — How Do I Protect My Network/Devices?

If you absolutely had to share a network with a user who had a very lax approach to security and was frequently hacked (1-2x month for over a year now), what might you consider doing to secure your ...
1
vote
1answer
35 views

Can sshd block IPs with failed attempts or is a tool like denyhosts or fail2ban necessary?

I am only indirectly familiar with denyhosts (and only just discovered fail2ban) and they certainly seem like worthwhile tools. However, after looking through the options for sshd_config I am trying ...
4
votes
1answer
116 views

Explain the last part of how Mitnick hacked Tsutomu Shimomura with an IP sequence attack

I was reading up on why TCP ISNs need to be randomized, which led me to this write up by Tsutomu Shimomura. I understood how IP address spoofing and predicting the ISN helped the attacker establish a ...
0
votes
2answers
88 views

Safe to use setuid with absolutely no input?

I have a shell script which syncs some files from a remote source and I have a pretty typical HTTP server set-up. There is a user who owns the files served by the HTTP server and a user which runs the ...
0
votes
0answers
27 views

Improve the security of a website implementing the least privilege principle [duplicate]

I am a beginner and I am trying to program a secure website to improve my skills and knowledge. I am under Linux and I am using LAMP with php. My website is similar to a social network so people will ...
0
votes
0answers
104 views

Improve the security of a website implementing the least privilege principle

I am a beginner and I am trying to program a secure website to improve my skills and knowledge. I am under Linux and I am using LAMP with php. My website is similar to a social network so people will ...
4
votes
3answers
967 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: ...
3
votes
1answer
239 views

My sendmail started sending spam; what is causing it to do so? [closed]

Today my sendmail service started sending e-mail to various addresses. /var/spool/mail: From MAILER-DAEMON@noxcommunity.com Fri Jan 30 22:15:30 2015 Return-Path: ...
9
votes
1answer
1k views

Is Java vulnerable to glibc GHOST Vulnerability in Linux?

I see on our RedHat Linux platform that "java" process has dependency over glibc library: [root@hpproliant1 ~]# ldd /usr/bin/java linux-gate.so.1 => (0xffffe000) libpthread.so.0 => ...
1
vote
2answers
230 views

How should I deal with adware in chrome on ubuntu?

I use chrome (but also have firefox) on ubuntu 14.04 32-bit. Recently I started getting popups from 'softwareupdaterlp.com'. I had the sense to realize it was not legitimate and I didn't click install ...
17
votes
3answers
2k views

Why doesn't Linux randomize the address of the executable code segment?

I've recently been learning about how ASLR (address space randomization) works on Linux. At least on Fedora and Red Hat Enterprise Linux, there are two kinds of executable programs: Position ...
0
votes
1answer
49 views

Bogus HostName Causing Suspicion of Man In The Middle

I have servers on a LAN reporting my laptop with a bogus hostname. This is making me suspect a man in the middle attack. Here are some details: From an Ubuntu Linux 14.04 laptop, I logged into an ...
0
votes
0answers
116 views

Is there any method to prevent/trace ddos attack?

I have a debian linux server which run a few online game services. I have some competitors in this area and i think one of them is behind the ddos attacks. I have full access to the router, so I set ...
5
votes
2answers
4k views

Best method to sandbox X applications in ubuntu

What's the best way to sandbox an X application like firefox or thunderbird in ubuntu (going into the direction of what qubes os does, but only for single applications)? I know there are many ...
2
votes
2answers
56 views

Linux Repo Security

Can a registered 3rd party repo spoof critical packages (e.g libc6) and have them installed on apt 'upgrade' operations? What are the best ways (configuration) to help manage 3rd party repos to ...
1
vote
2answers
271 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 ...
3
votes
1answer
166 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 ...
2
votes
1answer
84 views

How does the Samba misconfigured '/etc/passwd' file security bypass vulnerability work?

I just found this vulnerability on http://www.securityfocus.com/bid/36363/references, which affects several samba server 3.0.xx. Can anyone explain more about this vulnerability? How this bypass ...
1
vote
2answers
103 views

About SHA1 in default Disk Encryption in Linux

Link to the Thread: Recommended options for LUKS (cryptsetup) I wonder what's the exact difference between SHA1 and SHA512. I know that SHA512 has a longer key but I've read that it doesn't matter ...
5
votes
2answers
732 views

Security of Linux Full Disk Encryption (Ubuntu / Mint) -insecure?

I'm wondering, why is Ubuntu and Mint using SHA1 for Full Disk Encryption? I heard several times that SHA1 shouldn't be used anymore because it is weak and it could be cracked. Could you guys ...
0
votes
0answers
30 views

Bruteforce with Hydra [duplicate]

I'm trying to use a Hydra script in the following scenario on localhost and Linux: After web form login, my app redirects to another page with header(Location: internalpage.php) I use this syntax ...
85
votes
3answers
13k views

Is a rand from /dev/urandom secure for a login key?

Lets say I want to create a cookie for a user. Would simply generating a 1024 bit string by using /dev/urandom, and checking if it already exists (looping until I get a unique one) suffice? Or should ...
1
vote
0answers
70 views

Is there any security risk with adding a **root's** public key to the local user's authorized_keys (so root to login as a user non-interactively?)

Background: I want to try unprivileged lxc containers a try on my small web server (hosting 2-4 users). Since the server is shared among friends, we decided to separate our services from the machine ...
2
votes
1answer
94 views

Upload a file into directory with public write access

I know it is not right to set a permission for the folder as 777, but if it is done so will it be possible to upload a file into that directory without ftp access ? Here is what I mean Lets say the ...
3
votes
1answer
110 views

Key generation: Differences between GnuPG classic, stable, modern?

I plan to create a 4096 bit RSA&RSA key pair: gpg --gen-key --personal-digest-preferences SHA512 --cert-digest-algo SHA512 Is there any difference in generated key quality between versions 1.4 ...
3
votes
2answers
130 views

Firewall egress filtering / quick whitelisting

Suppose your Aunt or Uncle is easily fooled by phishing attempts and their computer has multiple root kits and key loggers running. Assume their computing habits will never change. Looking at his ...
15
votes
6answers
3k 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. ...
2
votes
5answers
143 views

Why can't just any program use his own file-system-access-system?

This may sound stupid for everyone who knows more than me about the UNIX-System and security in software: Imagine you have a program trying to cause harm by deleting files. You just do something like ...
3
votes
2answers
82 views

How to securely install software on Ubuntu?

How to install a software like Sublime Text on Ubuntu 14.04 LTS and mitigate against a MITM attack? There is a PPA available, but the PPA must be added manually. I don't see any PGP keys or MD5 ...
7
votes
2answers
196 views

List all files with only arbitrary file path read, but no directory listing nor sudo

I have found a path traversal vulnerability that allows me to read any path on the server that does not require sudo. To fully exploit this, I would like to know which files exist in each directory ...