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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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36 views

How do I fix: SSL/TLS: Report Weak Cipher Suites for Ubuntu Server [on hold]

I ran a vulnerability scan and I got these results for ports 993, 995, and 5432. I am running Dovecot for POP3S and IMAPS and Postgres for port 5432. I got these results from the vulnerability scan: ...
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2answers
100 views

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

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
71 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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0answers
123 views

So many weird things, need Security experts advice

I am in Beijing, China. I was trying to install shadowsocksR. Somehow my installation got completely messed up, so I decided to reinstall Ubuntu. There are many things weird like a missmatch for ...
1
vote
2answers
94 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
vote
1answer
30 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
votes
2answers
242 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 ...
0
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0answers
31 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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0answers
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 ...
1
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1answer
49 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
70 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 ...
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0answers
23 views

Why is Veracrypt showing 2 created partitions?

I wiped my 1TB Samsung 850 Evo SSD and I just used veracrypt to perform full disk encryption with it. I have another HDD drive as well that I've done this with. The HDD is sdb, and the EVO is sdc. ...
2
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3answers
2k 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 ...
0
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2answers
79 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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0answers
59 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 ...
0
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0answers
116 views

Man in the middle-attack

I'm trying to do a MITM-attack on my Ubuntu platform. After some searching arounf at the internet I'm doing everything correct as follow: sudo arpspoof -i wlan0 -t Victim-IP Router-IP sudo arpspoof -...
0
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1answer
100 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
48 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
116 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
votes
2answers
72 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
254 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?
45
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5answers
13k 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
votes
1answer
86 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
90 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
60 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
votes
1answer
38 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
votes
1answer
109 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
191 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
vote
1answer
62 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
182 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
50 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
vote
2answers
94 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
votes
1answer
86 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
134 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 $ ...
3
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0answers
137 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 ...
1
vote
0answers
201 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
votes
2answers
373 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
vote
3answers
195 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?
3
votes
1answer
122 views

Is there a security tracker aggregated file for Ubuntu server like Debian has?

Debian has a JSON file containing all CVE<->Fixed package versions map. Link: https://security-tracker.debian.org/tracker/data/json Does Ubuntu have something similar?
16
votes
1answer
491 views

Password shown on screen after crash on Linux, any idea why?

So, my computer crashed during the night and when I came to work in the morning I had the following screen on. I did not type the password a single time after the crash. It appears to be related to ...
2
votes
1answer
521 views

2ip.io/privacy/ and 'Defining tunnel (two way ping)' on SOCKS5 proxy

I was able to setup my first proxy server on Ubuntu 14 using danted. However, when I visit 2ip.io/privacy/ and run their privacy test, they return: Defining tunnel (two way ping) found This is ...
55
votes
3answers
17k views

Why has Ubuntu 18.04 moved back to insecure Xorg?

After reading Xorg becomes the default display server again and considering the security risk of xorg, I am wondering why the developers left Wayland. The fact that a few programs do not work on ...
1
vote
0answers
74 views

SUID not executing as root [duplicate]

I am trying to learn about SUIDs and have run into bit of a stumbling block - I have a ubuntu 16.04 system. I have set a few default binaries such as vim, find et al. to have SUID permissions as ...
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2answers
104 views

Why have distributions default HTTP package sources instead of HTTPS [duplicate]

Many distributions have HTTP links in their sources list for packages. Proof: https://docs.parrotsec.org/doku.php/mirrors-list https://docs.kali.org/general-use/kali-linux-sources-list-repositories ...
2
votes
2answers
326 views

VPN doesn't function properly on google websites

Why do google sites display content in my original country's language even if i'm connected to the internet through a VPN? For exapmple: google.com and youtube displays content in my actual language, ...
0
votes
1answer
50 views

Disable guest access in / directory Ubuntu [duplicate]

Follow up from: https://stackoverflow.com/questions/49703000/how-to-see-into-guest-account-filesystem-from-root I am root, and I need to restrict write or read access to / directory for a certain ...
1
vote
1answer
38 views

How to verify Ruby on Rails projects are at current patch levels?

I've got a few Ruby on Rails systems running Ubuntu 14.04LTS. The Ubuntu version of supported Ruby is 1.9.1 but the developers use a Gemfile and Bundler which (AFAIK) installs Ruby (and gems) out-of-...
1
vote
2answers
226 views

Malware techiques via Linux Chrome and its effects, non-root

Is it possible to visit a website with Chrome on Ubuntu and have that site execute shell code on my machine without explicitly downloading anything nor click on some Chrome execute question/popup? If ...
3
votes
2answers
341 views

odd ip address connected to my box

Today i went to the library. I was looking at my netstat -an output and i saw this. tcp 0 0 127.0.0.1:6379 127.0.0.1:46376 ESTABLISHED tcp 0 0 127.0.0.1:46376 ...