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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458 views

How to install client certificates globally for Google Chrome in Ubuntu?

I am trying to install a client certificate to Google Chrome running on Ubuntu. I want any user who logs in to Ubuntu to be able to use this client certificate in Chrome. Even better if I can create ...
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2answers
138 views

Did someone connect to MySQL from outside?

I have an Ubuntu server with a MySQL database that is only accessed from localhost. Is there any default mechanism in MySQL (or Ubuntu) that logs connection attempts, so I can check if the database ...
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3answers
7k views

Spoofed MAC address with macchanger but cant connect to internet

So I used macchanger to spoof my mac address with these commands: sudo ifconfig (interface) down sudo macchanger -m (mac_address) (interface) sudo ifconfig (interface) up If I stop here I will not ...
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1answer
2k views

What are all these connection attempts in my firewall log?

I've read many similar answers, but they all dealt with machines that were running publicly accessible services. In my case, I have a (newly installed and fully patched) Ubuntu machine that is used as ...
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5answers
15k views

How to block all porn websites from firewall?

I want to block all porn websites and similar contents in my Windows 7 PC using Windows firewall. Till now I can block it by inserting sites one by one. Is there any category defined for such sites or ...
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2answers
90 views

What does ModSecurity bring to my hosting account?

I read about the hack at Ubuntu Forums yesterday. Since we hold customer data things like this always makes me worried, and I look to minimise our risk of attack. There is an option to enable ...
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1answer
286 views

My mouse sometimes move without reason. Could it be a virus persisting Ubuntu reinstalls? [closed]

I am running Ubuntu Linux and I have reinstalled the system several times but sometimes I still feel like somebody gets remote access to my computer. I'm not running any software like Team Viewer. I ...
4
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1answer
8k views

Security implications of using SETCAP CAP_NET_RAW

In order to get around the 'problem' of applications requiring root privileges to run, I'm using: sudo setcap CAP_NET_ADMIN+ep "$(readlink -f /usr/sbin/app)" sudo setcap CAP_NET_RAW+ep "$(readlink -f ...
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2answers
439 views

Is dereferencing a null pointer in C a security risk if the program isn’t a daemon, but a small script lauched as a separate process for each request?

The following code is part of a program that is spawned at every request by the nginx’s ruby on rails script : static void time_t_to_dos_time(time_t user_supplied_time_t, int *dos_date, int *dos_time)...
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2answers
158 views

How to best manage multiple applications using the internet with Firewall

Im not new too Linux (Ubuntu 14.x) however I must admit that I have never bothered with a Firewall until now. Im currently using Ubuntu's inbuilt firewall (UFW) with a graphical plugin (GUFW), which I ...
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3answers
179 views

Is it safe to manually patch bugs on an outdated operating system such as Ubuntu 10.04?

How do I manually patch security bugs safely without damaging the system for information security purposes on my Ubuntu system that I am running on one of my mobile computers? I need to find packages ...
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2answers
943 views

Safe to connect a USB to Linux?

A "friend" offerred me a USB with files. I plugged it into my Ubuntu (version 12 or 14, don't remember) PC and an error appeared (don't remember exactly what was written..). So I wasn't able to browse ...
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52 views

Snort Modules Tweaking

I want to tweak and add new functionalities to snort code(Preprocessor)(v2.9.8). So,i have installed snort using source code,on ubuntu 14.04,however due to unknown problems,functionalities aren't ...
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0answers
2k views

Apache Web Server ETag Header Information Disclosure Weakness

How this vulnerability allow remote attackers to obtain sensitive information likes inode number and child process though ETag header ? and how to locate path to a file from inode number ?
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2answers
744 views

How can you be sure that there is a virus on your computer?

Am I being paranoid? I'm seeing signs of a virus everywhere on my computers but I have no way of being sure. I've tried scanning with Windows Defender multiple times but haven't found anything. My ...
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1answer
209 views

Getting Operating System Username using MySQL SQLi

Suppose I have a website which has SQL injection vulnerability and I got the database schema etc. Is there any means by which I can get the operating system username or the SSH username? Asking from ...
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1answer
1k views

Does KDE System Tray Extra Items “Clipboard” have the same security threats as the system clipboard?

Does the clipboard under kUbuntu's KDE System Tray > Extra Items "Clipboard" have the same security threats as the system clipboard? The following articles point out the insecure nature of the ...
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2answers
188 views

Can going to a bad website on firefox, or installing a malcious firefox plugin, infect other parts of my home folder on a Linux system?

BTW, I don't mean root, just a plain user. I'm worried because I'm scared that if I do such things I could infect my Chromium folder. I got a huge case of OCD.
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1answer
101 views

Is it a good practice to forbid IP access to port 80?

I see some sites have blocked there port 80 (or 443) to be accessed by IP. When you access by IP, an Nginx forbidden page shows up (with there OS version). My question is does it affect any side of ...
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4answers
309 views

Is the Linux / Debian software and package-management ecosystem secure?

My basic question is this: When we are using the Linux / Debian apt-get or yum package system, we're placing a lot of faith in that the packages we're downloading and installing are secure. For that ...
3
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2answers
1k views

Aireplay-ng doesn't work properly on Ubuntu

I want to do De-auth attack on Ubuntu 14.04 using Aireplay-ng. I am using alfaawus036h, so when I tried it on Kali or Backtrack, after plug in, it worked fine and there was no problem. but when I ...
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1answer
234 views

Is this way of client-side SSL secure enough, to keep hackers away from my web app?

I'm wonderying if the following steps are enough to protect my cloud service, in a meaning that non-authorized users can not play with my web app? In other words, is it possible to bypass this kind ...
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1answer
788 views

How to protect my server from continous login attempts (Ubuntu)

This is the log of my server: Mar 25 16:49:51 f4arelay sshd[10831]: input_userauth_request: invalid user git [preauth] Mar 25 16:49:51 f4arelay sshd[10831]: pam_unix(sshd:auth): check pass; user ...
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1answer
227 views

Are Ubuntu updates signed by a central authority?

When updating Ubuntu with the default setup, do updates need to be signed by multiple people, or is it a single person who controls what updates to sign? The reason I'm asking is that if a single ...
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1answer
104 views

External Hard Drive Operating System [closed]

If I put a OS onto a External hard drive, would it allow viruses to infect my internal hard drive?
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1answer
1k views

Sqlmap, how to move forward? [duplicate]

So, I'm using Sqlmap for a while now to test the security for my company (we're too small to have IT guy and I'm the closest they got for now), I already managed to access the database remotely and ...
8
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1answer
77 views

What are the recommended directory ownership & permissions for hosted websites?

So, I'm not sure what are the recommended directory ownership and premissions for directories of my websites. └── var └── www ├── website1 │   └── public_html └── website2 ...
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3answers
2k views

Why should one bother encrypting the harddisk in linux if one can easily recover the root password?

If you have physical access to a machine, it's pretty straightforward to recover the root password thereby skipping the whole point of having an encrypted drive. Am I missing something here? EDIT: ...
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6answers
10k views

Why is disabling root necessary for security?

This page on server hardening claims: Disabling the root account is necessary for security reasons. Why is disabling the root account necessary for security reasons?
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1answer
438 views

AirVPN, DNS Leaks on Windows 8.1, but not Ubuntu

I've noticed when I visit dnsleaktest.com using Windows 8.1 & Chrome a bunch of UK IP addresses (Belonging to my ISP) are displayed alongside the Netherlands IP address I should be appearing as (...
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1answer
246 views

How to patch haproxy for OpenSSL vulnerability USN-2830-1

This is regular security task, I have a number for servers running HAproxy on ubuntu 14.04 LTC on AWS. Since USN-2830-1 is a OpenSSL vulnerability I believe we must patch our HAproxy instances, but on ...
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1answer
7k views

How does Nautilus store passwords on Ubuntu?

When I mount a LUKS volume, I get these options: Forget password immediately Remember password until you logout Remember forever I assume the first is the safest, and I can work on the files until I ...
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1answer
621 views

How can I check whether file modified time has been spoofed on ext4?

On Debian based system (Ubuntu 14.04.3 server specifically), using ext4 filesystem. How would I discover if files have been changed, but the modified times have been made to look like the files have ...
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2answers
198 views

Protecting data on server from illegal physical access

I am running Ubuntu (14.04) server and I saw this question: How do I reset a lost administrative password? I wondered, because my server virtual machine is on the ESXi server, I don't know if ...
3
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1answer
118 views

Running rkhunter on Linux

Currently each time before an application and after an application is either installed or updated including regular patches, the command rkhunter --propupd is run, followed by the command rkhunter --...
4
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3answers
3k views

Can hackers access my webcam? [duplicate]

Can hackers gain access to a webcam without turning the webcam on? Can this be done on Ubuntu?
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1answer
253 views

Would placing a hardened virtual machine in a VPS provide more security?

I have been working with DigitalOcean for a while now and while I do like that they make it easy to start up with a fully functioning virtual machine ready to go. It makes me cringe a little though ...
16
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3answers
4k views

Breaching security of a notebook with full disc encryption when screen is locked

I am using full disc encryption on my portable computer (running Ubuntu). The setup requires me to enter a password during the boot sequence to access fully encrypted hard drive. There is no ...
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3answers
408 views

Fail2Ban keeps sending me logs of user banned, is someone trying to hack me?

I installed and configured fail2ban on my VPS a couple days ago, since installed, it keeps sending me emails saying that an IP was banned after failed login attempts. Firewall is on and fail2ban is ...
8
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5answers
2k views

I don't recognise my DNS server's address: does this mean I am compromised?

I'm using the Ubuntu GNOME Linux distribution as my desktop. Recently, it became impossible for me to connect to the Internet with it. When I checked its network settings, I saw that the DNS address ...
4
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3answers
1k views

How to choose a linux for learning? [closed]

I am beginner in Security. My first assignment is about "Linux firewall using IPTABLES" . I know about Ubuntu, backtrack and kali Linux. How to choose a Linux distribution to learn about security?
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2answers
12k views

Does having these ports open indicate any vulnerabilities?

I installed Ubuntu Gnome a couple of weeks ago along with a few packages and some software. When I scanned my localhost using Nmap, I got the following results. Are there any obvious vulnerabilities, ...
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0answers
525 views

ArpON not working

i'm trying to setup ArpON on my laptop running Ubuntu 14.04. I have a DHCP network so in the configuration i uncommented the DARPI line, then set RUN to yes. Then i started the daemon with sudo ...
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3answers
20k views

Are there ransomware infections of Ubuntu Linux in the wild?

Due to the recent media coverage of ransomware attacks several people for whom I've provided personal computer support in the past have expressed concerned. The majority of these people are running ...
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1answer
971 views

How is a exploit code mmaped in user space executed in kernel space?

I am reading about a Ubuntu-12.10 security exploit CVE-2013-1763 which describes the vulnerability of stack buffer overflow that can be exploited to escalate privilege of a process and gain root ...
5
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2answers
1k views

Detect when I do brute force attack and block the connection

My server (Ubuntu + LAMP) is infected, as I receive security alerts from the sites attacked from my IP. your Server/Customer with the IP: ********** has attacked one of our servers/partners. The ...
5
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3answers
3k views

How can I defend against malicious GET requests?

My server is getting hit with a variety if requests like the following: Started GET "/key/values" ActionController::RoutingError (No route matches [GET] "/key/values") Started GET "/loaded" ...
7
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2answers
2k views

*NIX shadow file password format

I'm trying to get shell access to a router and have managed to retrieve its /etc/shadow file: root:$1$$N76hdwGfg11g0KdKbtyh21:0:0:root:/root:/bin/bash I've tried to use john to crack it but couldn't:...
18
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3answers
3k views

ISO27001 and Linux/Ubuntu

My company has an ISO 27001 certification. They provided me a new laptop with Windows 8 OS in it. I asked if I can have a Linux/Ubuntu OS installed, they said that it is not possible due to the ISO ...
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1answer
205 views

Mystery URL in iftop

So this may be more appropriate for serverfault, but it seems like it belongs here. I was watching iftop on a server I control that can send data to arbitrary sources but can theoretically only ...