Securing Linux systems and applications; understanding Linux security features.

learn more… | top users | synonyms

1
vote
2answers
19 views

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 ...
0
votes
0answers
13 views

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

How can I know what are all different types of events linux generates. I can get this from logs but reading logs and noting down ID's are very much time expensive and all the events will not triggers. ...
3
votes
2answers
77 views

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

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 ...
0
votes
0answers
22 views

Clarification about logging

Firstly, I apologize for asking this kind of noob question. But, for some time, I've got so much confusion about computer message logging. As the article on Wikipedia said, Syslog is a standard for ...
3
votes
1answer
73 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 ...
1
vote
0answers
26 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
52 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 ...
2
votes
2answers
443 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 ...
0
votes
1answer
56 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 ...
0
votes
1answer
45 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. ...
2
votes
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", ...
0
votes
1answer
34 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 ...
0
votes
1answer
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 ...
3
votes
0answers
35 views

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 ...
2
votes
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 ...
17
votes
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 ...
0
votes
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. ...
2
votes
1answer
169 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 ...
0
votes
0answers
13 views

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 ...
0
votes
0answers
30 views

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 ...
170
votes
5answers
86k views

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 ...
0
votes
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?
14
votes
4answers
5k views

How to prevent BadUSB attacks on linux desktop

What can I do to protect my linux laptop from BadUSB attacks as described here? Perhaps writing an appropriate apparmor profile would help?
5
votes
2answers
2k views

Benefits to BlackArch over Kali

Besides BlackArch having a cooler name and the whole Ubuntu vs. Arch Linux thing, what are the relative benefits of BlackArch over Kali? Are the tools broadly the same, or does one have better ...
0
votes
1answer
74 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 ...
4
votes
2answers
61 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 ...
0
votes
0answers
53 views

/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 ...
0
votes
1answer
85 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 ...
4
votes
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 ...
0
votes
3answers
202 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?
1
vote
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 ...
1
vote
2answers
320 views

Directory traversal & default filesystem permissions (755) for web server

I'm trying to get a better understanding of the potential security holes my default filesystem permissions might be creating. It appears I am capable of traversing my filesystem, serving simple php ...
5
votes
2answers
270 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 ...
4
votes
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 ...
0
votes
2answers
126 views

“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 ...
1
vote
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 ...
2
votes
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 ...
1
vote
1answer
26 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 ...
8
votes
1answer
470 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 ...
8
votes
2answers
2k views

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 ...
2
votes
2answers
161 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 ...
1
vote
1answer
61 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 ...
0
votes
0answers
32 views

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 ...
-2
votes
2answers
770 views

How to completely password protect login into Ubuntu 12.10?

I am running Ubuntu 12.10 on my laptop and I would like to make a set up such that without a login password, no one would be able to login into my system. Currently it seems that one can, quite ...
1
vote
1answer
78 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 ...
2
votes
2answers
116 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 ...
0
votes
0answers
27 views

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 ...
14
votes
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 ...
1
vote
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 ...
4
votes
1answer
5k views

Fail2Ban does not ban failed root login attempt

I have a small server which only open ports are ssh, http and https. I have fail2ban installed and set up so that after 3 failed attempts someone gets blocked for 10 minutes (thats the dafault I ...