Questions tagged [ubuntu]

Ubuntu is a Linux version derived from Debian. For questions about Ubuntu that are not about security, please post on [AskUbuntu.SE].

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How can I make my website safe? [closed]

Please anyone who's keen on safety: I have a server on Ubuntu 16.04 using Node.JS and proxy as eNginx last version all of them - and a website such as a forum wehre people can sigh up and write down ...
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31 views

How can I SSH into my server when SSH is blocked on the public network I'm connected to? [closed]

What's a quick and simple way to connect to my server over SSH when the SSH is blocked on the network I'm connected to? I'm running MacOS on the client side and Ubuntu 18.04 on the server side. My ...
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1answer
88 views

How to keep backup servers safe?

I use duplicity on a few Ubuntu servers to encrypt backups and send them to a backup server, which then sends another copy to rsync.net, and then, once a week, give it or take, I download these ...
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1answer
87 views

Maintaining root SSH access on Linux Ubuntu even after losing it? [closed]

Consider I have root ssh access to a Linux server (Ubuntu 18.04 LTS). What is the best way to maintain access even after losing ssh access? Are there any tools out there to help maintaining ...
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5answers
4k views

How to use FDE without needing to share the encryption password

We have an AI model which needs to be deployed on premise. The hardware will be provided by us, so we can do what ever we want on the device. The device is a mini PC running Ubuntu 18.04. The UI is ...
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0answers
37 views

How to do a SSL MITM for all programs trying to access the internet on my local Ubuntu

How to do an SSL MITM for all programs trying to access the internet on my local Ubuntu. When a program on my local machine tries to access the internet using https I would like to intercept and ...
6
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1answer
91 views

Printing document on usb drive with confidential information on multi user computer

I have a pdf file with confidential information on a usb flash drive. This document needs to be printed on a multi user Ubuntu system. I want to prevent other users from seeing the content of the ...
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1answer
37 views

UFW Blocks some IPs which are trying to attempt a connection to the server

UFW‌ Blocks some IPs which are trying to attempt a connection to the server. I checked most blocked IPs in abuseIPD website and all blocked IPs are reported for brute force attack and/Or ssh spamming ...
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1answer
61 views

metasploit openvas plugin not connecting to OpenVAS9-Manager

I recently installed openvas9 following this guide. I can log into the web interface on port 4000 just fine, and I ran a scan on my metasploitable VM for testing, and it seems good. Now I wanted to ...
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38 views

Hacking attempts to our server - what does this code do? [duplicate]

Every so often I go back and check our server and find random files uploaded to the domain root directory. They are seemingly cryptic and have names like css2.php db_model.php ....
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1answer
187 views

For security purposes, can I use vpn with ufw to allow traffic only from the vpn on ubuntu?

Is this possible? If not through ufw then some other software or iptables? How should I set up the ip tables? Assuming my public ip is known (and I don't want to change it), would it provide complete ...
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1answer
83 views

Can a malicious optical disc infect Ubuntu without user action?

Assuming that a malign user has unlimited resources at his/her disposal to infect a computer running Ubuntu, but he/she is only limited in transferring the malware through an optical disc (CD, DVD, BD ...
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34 views

Saved browser login information disappearing [duplicate]

I recently noticed that my browser (Chrome) is not saving my login state for websites anymore. The first time it happened I didn't thought much of it but it happened again and again. I also noticed ...
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0answers
74 views

Find files with autopsy [closed]

I had an Ubuntu 14 machine. A couple of days I installed Ubuntu 18 on this machine. I'm trying to recover some files from the previous installation. I'm using autopsy. I think I'm doing something ...
3
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1answer
183 views

Is suspend-to-ram really a meaningful risk for Full Disk Encryption?

Ubuntu offers full disk encryption relying on luks. An often recurring area of criticism is the fact that Ubuntu disables hibernation by default while suspend-to-ram stores the private keys in the ram ...
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2answers
106 views

How does a hacker get access to my files if he got access to another user's files on a shared server? [closed]

I host files on a shared server with Ubuntu 14.04. How does a hacker get access to my files if he got access to another user's files and how do I prevent it?
2
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1answer
415 views

Cannot exploit stack-based buffer overflow with ASLR-disabled, since RSP differs heavily between executions?

I have made a little toy program, compiled with ALSR disabled, that I want to exploit using stack-based buffer overflow: // gcc stackexec0x1.c -Wl,-z,execstack -no-pie -fno-stack-protector -o ...
1
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2answers
452 views

How to get result from airdump-ng on Ubuntu 18.04 LTS?

Issue: when I run airodump-ng wlp3s0mon, no results appear. I recently installed all kali linux tools on Ubuntu 18.04 LTS from this git repo https://github.com/LionSec/katoolin My chipset is the ...
1
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1answer
88 views

Permissions for Azure OMS Agent files

I have two files that the Azure OMS agent reads/writes from that are world writable files. Our vulnerability scanner (rapid 7) is picking these up as vulnerabilities. It's also poor practice in ...
2
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2answers
256 views

Would an Ubuntu server accessible from the internet be hacked within days?

I created an Ubuntu server on Digital Ocean to deploy my app on. Less then 24 hours later, I log in to the server and see this: 18 packages can be updated. 7 updates are security updates. I install ...
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0answers
39 views

Is it possible to contract a virus on Ubuntu/Debian from an Apache Nutch web crawl?

For the fourth time now I have contracted a virus while doing a large web crawl on webmd.com. I'm not certain that this is where the virus is coming from but I don't see what else it could be. Is it ...
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40 views

There are cached icons and screenshots from another person, am I hacked? [duplicate]

I'm running Ubuntu bionic 16.04 LTS and there are being constantly added new files into the ~/.cache/gnome-software/ directory. I've uploaded all of them into this new GitLab repository, so that you ...
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1answer
204 views

Is it a security risk to run master process of nginx as root?

I'm using nginx (Port 8888) as a reverse proxy for my web server running over 8080. In the traditional way, nginx master process runs as root and spawns the child processes with user www-data. Is it ...
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1answer
246 views

Would sniffing all network traffic from android device to check for spyware be a viable solution

I suspect that my Google pixel (Android 9) phone has some sort of a spyware installed. There are no obvious symptoms like overheating, extreme data usage, or battery draining at an unusual rate. But I ...
3
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3answers
8k views

New Linux virus “watchbog”. What could be the cause? [duplicate]

This question had already been brought up here, but was poorly answered with generic answers, like reinstall everything and no actual solution and cause. So here's my story: There is a new virus out ...
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2answers
201 views

Security best practises for my first ever Node, Mongodb, Nginx production app on a Ubuntu VPS

So as the title says I'm just deploying my first ever app in production. Because I don't have experience, I was told to ask someone who knows this stuff. So how should I ensure the best security for ...
0
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1answer
123 views

How can I found a source of HTTP request in Wireshark?

There are weird requests to/from the AWS: and another one to/from 177.143.198.104.bc.googleusercontent.com: ( http://whois.domaintools.com/177.143.198.104 ) I use Ubuntu 18.04 Desktop, web browsers ...
1
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1answer
250 views

dhclient cloud-init /var/tmp process

There's a process that's running that I'm trying to investigate why its running and what its doing. The server is a Linux Ubuntu server running on AWS. Running 16.04. The process in question is: ...
2
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1answer
102 views

Do openssl CA certificates get updated with apt-get upgrade?

I use Ubunut 18.04. I need to know if OpenSSL CA certificates that are in this file: /etc/ssl/certs/ca-certificates.crt get updated when I upgrade my system using: apt-get upgrade? I have a ...
0
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2answers
157 views

Boot from live usb to avoid being spied on

Suppose the government wants to spy on you using government-designed malware. If you then want to visit sensitive pages on the internet, would it be more secure to use Tor browser within a USB - live ...
2
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2answers
153 views

How do i know if my ubuntu apache version is secure?

I am running Ubuntu 16.04 LTS and checking dpkg -l apache2 gives me version 2.4.18-2ubuntu3.9. How do i know that 2ubuntu3.9 has the latest security patches listed here at https://httpd.apache.org/...
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1answer
1k views

How to switch from Ubuntu 18.04 to kali linux? [closed]

I am using now ubuntu 18.04.1 and i wanna make dual boot with kali linux. How to do that?
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5answers
16k views

Should I close port 80 forever and ever since the 2018 Google-indicated web-security initiatives?

I often establish Ubuntu-LAMP environments on which I host a few Drupal web applications that I myself own (I don't provide any hosting services and never done so in the past). Whenever I establish ...
2
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1answer
149 views

Containerization vs. Chroot in shared hosting

Forgive my rudimentary understanding of server security, but one thing I've always struggled with was understanding how to setup chroot to separate folders (which are discrete WP installations) in a /...
6
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2answers
2k views

Why can 'Others' read files by default in Ubuntu?

I am trying to figure out why when creating new files and directories in, let's say, the Documents folder, they get assigned, by default, the following permissions: -rw-rw-r-- 1 hello world 0 Nov ...
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2answers
100 views

How can i access any useful information in a wordpress site?

While penetration testing for a university assignment, I found an exploit that might be the one the teacher has been hinting for, found here: https://www.exploit-db.com/exploits/45439/ I used it and ...
0
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1answer
70 views

Read-only to the root user

Is there a permanent and secure (as in integrity) way to make the entire Ubuntu system of a VPS (virtual private server) read-only to all users (including the root user)?
2
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1answer
42 views

Limit rights for user applications

I have a website, where users are available to upload small applications which runs 24/7 on my server. So if the user upload an application, some folders will be created: /{USER_ID}/{APP_ID}/ (if ...
3
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1answer
112 views

How to enforce on the OS level to recognise only certain keyboards

I give employees AES wireless keyboards. I would like to enforce the OS to only recognise the keyboard we supply. Is that possible? Assuming my employees OS are Windows 10, Ubuntu, Mac OSX. How could ...
5
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5answers
246 views

Unix Privilege Escalation: “sudo must be owned by uid 0 and have the setuid bit set”

It seems protections are harcoded into sudo that prevent the binary from executing as a low-privileged user. Running it in Ubuntu as a normal user returns the following error: "sudo must be owned ...
1
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1answer
362 views

OpenVPN one account multiple servers & Load Balancing

I have recently been experimenting with OpenVPN. My aim is to create a group of servers in different locations with a single username and password for each user stored in a central database. For ...
1
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1answer
491 views

Files on external drives executable by default with exFAT or NTFS under Ubuntu

On Ubuntu, if you use (external) drives formatted as exFAT or NTFS, i.e. not ext4 or something made for the UNIX world, you may end up with a situation where all files are executable. This is because ...
2
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1answer
59 views

Securely Download lubuntu from Non-Ubuntu System

The recommended way to find out which public key you need to verify the Ubuntu hashes is to attempt to check a signature of the hash file (both of which were downloaded in the clear). This produces an ...
1
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2answers
241 views

Add main user account to docker group

I recently installed ubuntu on my home system. As I am going to mainly use it for machine learning research, I tried to set up a python environment. I tried doing this with docker to make things ...
0
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1answer
130 views

Unexplained DNS connections on boot

I was on an Ubuntu VPS today, with a bind9 DNS server (without DNSSEC configured) installed and running. Immediately after booting the machine I ran: netstat -tanp And received this output: Proto ...
0
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1answer
214 views

Is my Vino server being attacked?

I installed vino on LUbuntu 18.04, and configured and started my vino server according to https://askubuntu.com/a/530196/1471 without understanding what the commands mean: $ export DISPLAY=:0 $ ...
4
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1answer
232 views

Weird attack making my server CPU super high

I noticed that my server CPU is super high and the reason is grep "A" command After a deep look, that what I've found in my active internet connections list (netstat -tupn) tcp 0 0 ...
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0answers
260 views

Buffer overflow experiment: shell code executed but got “failed to read 0 bytes” error

I've doing a buffer overflow experiment on a Ubuntu 16.04 VM (Linux ubuntu 4.10.0-28-generic #32~16.04.2-Ubuntu SMP Thu Jul 20 10:19:48 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux) and got a puzzling ...
3
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2answers
688 views

What is this SSH attack, am I hacked?

I see this in my Ubuntu server's log file: in my ssh my user is root but i see other user Disconnected like "teamspeak", what does that mean? auth.log Jul 3 21:39:01 vmi189193 CRON[25937]: ...
1
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3answers
215 views

When hardening a LINUX system what command line tools would you remove first in order to make an attackers life really difficult? [closed]

When hardening a LINUX system what command line tools would you remove first in order to make an attackers life really difficult?