Securing Linux systems and applications; understanding Linux security features.

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Joomla Linux Permsions

I installed Joomla 3 to /var/www/html directory in Cent OS 6 server. Currently it /var/www/html is owned by apache:apache. What is the recommended permissions for Joomla installation on Linux in ...
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1answer
41 views

How to know different types of events and there ID's in linux

How can I know what all types of events generated by Linux. I can get this from the logs, but reading logs and noting ID's is very time consuming. All events might not be triggered. I need this ...
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3answers
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Ping Input box on web server vulnerable to piped commands?

Scenario is this. I have logged into a web server as admin through the Login page in browser. it has displayed me with a home page of sorts that has an input box with a button next to it saying ...
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3k views

One liner to create passwords in linux?

How do you create a readable password using bash with one line? What if i'm looking for 128 bits of entropy? EDIT By readable I mean the 94 readable ascii characters (without space). It can use less ...
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4answers
105 views

How do I encrypt external drive with Password which is compatible with both Linux and Windows? [on hold]

I wanted to encrypt my external drive with password, which is compatible in both Linux and Windows. Truecrypt is an option. But the development of it is stopped few months back. I came across ...
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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 ...
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1answer
57 views

How negative are virtual machines (vms) to /dev/urandom?

I looked at the questions here and here. This then piqued my interest as I've recently been involved with looking into FIPS compliance, and in my vm environment /dev/urandom compliance testing ...
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2answers
535 views

Disable SSLv3 system-wide for all clients?

After reading about Poodle secutrity bug, I have disabled SSLv3 on my servers and browsers. But there are several clients that do not expose settings detailed enough via their own means of ...
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1answer
63 views

UEFI secure boot and rootkits

I heard that with UEFI secure boot enabled a custom kernel module that is not signed will not run, hence a rootkit might be difficult to install. Can a secure boot really block rootkit modules from ...
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1answer
46 views

jRAT virus on Linux

I dumbly downloaded a .jar file that contained jRAT. When run, it stalls, gives a FileNotFoundException, then crashes. When I ls'd, the jar was there. When I cd'd out and back in, the jar was gone. ...
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1answer
30 views

ASLR does not seem to randomize text section

I wanted to make some basic tests on Linux ASLR, so i wrote the following code : #include <stdio.h> void funct(){ int a= 0; } void main(){ int b=0; printf("funct : %p\n", ...
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1answer
35 views

Debian encryption is as safe as Truecrypt. Is this correct?

When I try to install latest debian to my pc, the wizard ask me to input a password to do FDE(full disk encryption). My questions are: What algorithm does Debian use? (Truecrypt = AES) Can I change ...
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45 views

How to get SSL certificate of a mail server?

I need to get SSL certificate of some mail servers. I know I need to do execute following steps. Do a DNS mx query on the domain name (dig google.com mx). Use the information to download SSL ...
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Linux, TRESOR and XTS

I want to switch from using LUKS for full disk encryption to TRESOR. TRESOR tries to prevent cold boot attacks by storing the encryption key in the CPU's registers. It uses the kernel's crypto API for ...
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4answers
65 views

Add a file as entropy source for /dev/random

What I have: A large file containing lots of secret, true-random bytes (yes, I'm sure they're not merely pseudo-random). I'll call it F. What I want to do: Tell Linux that it can use this file as an ...
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how to pass password file to openssl srp [migrated]

I'm trying to pass password to the openssl srp through a file using -passin param as below but im getting errors. openssl srp -verbose -passin file:password.srpv.attr -srpvfile password.srpv -add -gn ...
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0answers
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Private server security questions [duplicate]

I want to build my own server. It will have mail, ssh, and apache (slackware 14.1). Could you tell me what I should pay attention on when I secure my server? Should I install SELinux? It will be ...
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1answer
63 views

How to determinate if someone scanning my server?

How is possible to determinate if someone make requests with tools for pentesting? Is there any linux command?
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1answer
75 views

How would one go about setting up a system with security in mind? [closed]

I run a standard laptop at home (dual-boot Fedora 20 and Windows 7; the Windows side is almost never used). Soon my other computer will be working again; it will have Windows 8.1 and some flavor of ...
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/etc/shadow in old format, where is salt stored? [migrated]

In /etc/shadow I have entries such as admin:YtChlvAGYzva2:16318:0:99999:7:::. I know the original password and would like to generate the same hash somehow. However, running openssl passwd -crypt ...
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2answers
62 views

Does KASLR really provide more security against exploits?

I know all about how ASLR works, and how it has been implemented on both Linux and Windows systems. It provides an extra layer of protection that malware has to take into account. But nowadays with ...
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1answer
88 views

Find and kill process that create malicious connections

State Recv-Q Send-Q Local Address:Port Peer Address:Port FIN-WAIT-1 0 3640 my.public.ip.xx:https xxx.xx.xxx.xx:56206 SYN-SENT 0 1 ...
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1answer
171 views

Does dual boot hurt security?

On my laptop I have a well secured Linux installation that I would like to stay this way. It has in the past and could in the future contain confidential medical data I use for my study. I also have a ...
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3answers
57 views

Capture query to MySQL in Server

I want to capture queries to MySQL from my web-application on my Linux-based Server. MySQL port is 3306 and my web-application in on port 8181. So I started using tcpdump as follow: # tcpdump -x ...
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2answers
235 views

How secure is BSD sockets?

BSD sockets API was released in 1983. As it was implemented 3 decades ago and still being widely used, is it secure in today's scenario where every software has to be actively protected against ...
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2answers
273 views

Escalating from Apache shell to root

I have one noob question.I tried to exploit shellshock on my Slackware linux server, but after I connect with reverse shell and User Agent I get that I am apache user and apache user don't have too ...
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2answers
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“Shell shock” - exploitable when `system()` syscall or `exec(bash)`, right?

Is my understanding correct that in order to exploit via "Shell Shock", binary we influence needs to execute bash (and we need to have influence on command line)? Therefore, am I correct, that if ...
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1answer
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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 ...
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1answer
474 views

What does this attempted Shellshock exploit do, and has my website been compromised?

I grepped my Apache's access.log today for the now infamous () { string, and besides a bunch of what seemed like pings to check how many servers are vulnerable, I found this attempt, which looked like ...
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1answer
128 views

Can shellshock be used on a system with public webpages but restricted server access?

I want to know if my servers are still vulnerable under the following conditions... My servers are private - only myself and trusted developers have access to them We have enabled executables within ...
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2answers
162 views

what makes envirnments vulnerable/protected vs shellshock bug

I just tested whether or not my university's environment was vulnerable to the shellshock bug using env X="() { :;} ; echo busted" /bin/sh -c "echo stuff" (code from ...
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1answer
269 views

Has CVE-2014-6271 Shell Shock been mitigated completely what is the latest? [closed]

I have patched my system however CVE-2014-7169 claims that the fix for 6271 was incomplete. Sure enough if I run the command below: env X='() { (a)=>\' sh -c "echo date"; cat echo It appears ...
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Tunneling Remote Desktop from DMZ Windows server to my Listening Linux Server. How to?

I have a situation in a penetration test where I got a meterpreter on an internal (DMZ) Windows box, and I want to connect via RDP to it, however the RDP port is blocked externally. The box I hacked ...
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Is connecting to an open WiFi router with DHCP in Linux susceptible to Shellshock?

Source: http://lcamtuf.blogspot.com/2014/09/quick-notes-about-bash-bug-its-impact.html For the same reason, userland DHCP clients that invoke configuration scripts and use variables to pass down ...
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5answers
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What is a specific example of how the Shellshock Bash bug could be exploited?

I read some articles (article1, article2, article3, article4) about the Shellshock Bash bug (CVE-2014-6271 reported Sep 24, 2014) and have a general idea of what the vulnerability is and how it could ...
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1answer
81 views

Is this a secure way to connect with Tor?

I was discussing the use of tor with a friend, and he happened to suggest a way to remain secure when using applications on the terminal (Lynx, Nmap etc.) His suggestion was this: ssh-keygen -b 4096 ...
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How to relay broadcast traffic using ncat? [migrated]

I have 2 servers, 192.168.1.1 and 192.168.2.1. I want to relay any broadcast traffic (192.168.2.255) through 192.168.2.1 to 192.168.1.1. Here's what I'm doing to relay port 137 traffic, and it seems ...
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1answer
62 views

Am I safe to see a thumbnail of a downloaded images on Ubuntu 14.04?

I have downloaded an image that someone has uploaded to my website with a public upload form. My intention was to copy the file in a virtual machine and see the image from there; unfortunately, on ...
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2answers
2k views

Linux password changed. Is this an attack or a hardware glitch?

My Linux (Ubuntu 12.04) password suddenly changed last night and I'm not sure if this is an attack or just a hardware/user error. This is on a personal/non-server box. Several strange events led up to ...
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3answers
203 views

Are windows users passwords easier to crack than linux?

If i set the same password in both linux and Windows, is it easier for a hacker to break the windows password? If so why and how can i create a windows password in the same security level as Linux?
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1answer
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Linux Rootkit / BIOS Malware: What packages are necessary to get infected?

Everybody knows about the dangers of Rootkits / BIOS malware. What do you say about this countermeasure? In order to actually get infected the malware needs to use the OS to 'patch' the BIOS chip. ...
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2answers
117 views

Receiving sensitive data uploaded on a Web server, and remotely accessing it without exposing it to theft

Edit: I mostly used my university's guidelines on how to meet DPA standards and their own. I extrapolated a bit because encryption on a VM hosted by my uni that is already probably encrypted makes ...
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2answers
33 views

Ubuntu backup to only specific devices

I am looking into setting up a secure Ubuntu server with daily backups to two different external hard drives that will be swapped with the external hard drive that is stored in a safe deposit box. ...
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0answers
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Gnome-keyring iteration count location

I know that Gnome-keyring hashes master password between 1000 and 2000 times. It picks random number. I would like to ask where does it save this number, what is the location of that file? As far as I ...
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1answer
93 views

What are the options for acquiring disk image from a Linux computer that can't be removed from a crime scene?

If the suspect's computer is Linux, can you directly use tools such as dd or dcfldd on his computer to acquire the disk image? Or do you need to use forensic live cds like Helix, Penguin sleuth or ...
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3answers
108 views

Not replacing SSL cert on a rebuilt, formerly rooted Unix Server

If a server was rooted, to the point that we know a Perl script which creates a remote shell was placed on the filesystem remotely, and the server was rebuilt entirely, patching the original Apache ...
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2answers
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Where can I “hide” easter eggs for students learning about Linux security?

I feel like this isn't the best place to ask this (since there's no single right answer), but I can't think of a better place. If you have a better recommendation, could you please recommend it and I ...
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2answers
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Do `sudo` and `su` belong to capability-based security?

In Linux, do sudo and su belong to Capability-based security ? For example, when editing a system file, we usually need sudo or su to temporarily switch to user root. Does this example belong to ...
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6answers
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Unix execute permission can be easily bypassed. Is it superfluous, or what's the intention behind it?

The unix read permission is actually the same as the execute permission, so if e.g. one process has write access it's also able to execute the same file. This can be done pretty easily:First this ...
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2answers
775 views

I ran a netstat on my server and port 80 is listening, does that mean it is open and vulnerable to attacks? [closed]

Sorry I am just getting into Web Development and trying to learn more about servers and PHP, so I downloaded the LAMP stack on an Ubuntu14 OS and started an apache2 server. tcp6 0 0 :::80 ...