Content related to computer security., i.e. content about policies, mechanisms, etc. needed make sure data is not leaked or corrupted and services available in all circumstances.

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2answers
107 views

Is it evil to link to a crontab?

I think about doing something like: sudo ln -s ~/myCustomCrontab /var/spool/cron/crontabs/username because I'd like to have all customized files in my home directory. Possible risks I can think of ...
58
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6answers
5k views

Why does reboot and poweroff require root privileges? [duplicate]

To restart or shut off Linux from the terminal, one can use reboot and poweroff, respectively. However, both of these commands require root privileges. Why is this so? What security risk is posed by ...
0
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1answer
56 views

What are the right permissions to set to make files unreadable unless it's my main user accessing them?

Basically I didn't encrypt my Linux (Debian) partition when installing it. However I found a way to encrypt at least home folder so in theory I could put everything there which I want to make sure it'...
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0answers
35 views

Is insecure to give users permissions to apps in /opt? [duplicate]

I'm working with some apps (the best example i can give is Firefox Developer Edition) that i put in the /opt folder. These apps work perfectly until they need to apply and update, and that's because /...
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0answers
72 views

Does running fcgiwrap with nginx give the same added security as creating a new php-fpm pool for every site by hand?

Here's the nginx + fcgiwrap configuration I'm talking about. I don't understand what the main differences are between this kind of a fcgiwrap configuration and a nginx + php-fpm configuration. They ...
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0answers
28 views

How to get informed about EVERY incoming ssh connection (e.g. with no remote command specified)

The case I'm used to set up automatic reverse ssh tunnels to remote computers via my server with cron. Usually I use the following entry: @reboot sleep 300 && ssh -MNf -R xxx22:host:22 user@...
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1answer
17 views

Hide/Encrypt application configuration

Is there any way to hide/crypt software config files (services such as Apache web server , Varnish and so on) from boss and others?
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0answers
65 views

dirmngr does not start with proper home directory unless it is restarted

I am trying to follow these guidelines for gpg best practices: https://help.riseup.net/en/security/message-security/openpgp/best-practices but I am having trouble with dirmngr, which handles all ...
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1answer
41 views

Can't access web sites when running iptables script!

I have wrote script for protecting my machine: #!/bin/bash ssh=1.1.1.1 http='1.1.1.1 2.2.2.2' # Clear any previous rules. iptables -F # Default drop policy. iptables -P INPUT DROP iptables -P ...
0
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1answer
56 views

How to protect from chrooting to its linux partition and how to chroot it after using the protection?

I am currently using archlinux, It is possible to boot on an archlinux installation iso for instance, to mount my current archlinux partition and my boot partition and then to use arch-chroot. Then I ...
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1answer
107 views

Managing iptables for specific ips and ports

I disable firewall like so: #!/bin/bash iptables -F iptables -X iptables -P INPUT ACCEPT iptables -P OUTPUT ACCEPT iptables -P FORWARD ACCEPT Update I also enable my firewall: #!/bin/bash ssh=x....
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2answers
96 views

Storing application passwords in central location

Is there any secure local service that one should use for storing and retrieving organization wide application passwords? Most of the time we need authentication information in our scripts to run some ...
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0answers
15 views

Need Help to Solve Screenlock Bypass Issue for Expired User Account

I have created a script that I deploy to my children's computers via Salt. The script implements allowed working hours and has worked well, but one of my children have found a way of bypassing this ...
0
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1answer
34 views

How does JetBrains PyCarm IDE put files into directories outside of ~/ despite being run without sudo?

PyCharm is a lovely Python IDE by JetBrains that can be downloaded here. I have downloaded the free community edition, extracted (with sudo) it into /opt/jetbrains/pycharm and run (without sudo) /opt/...
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0answers
24 views

How to view WIFI devices names and signal strength [duplicate]

I want a cli utility or script that shows all the Wifi devices or hotspots or access points and their signal strength. I want to log this data using Python. I will write the logging script myself. ...
0
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1answer
54 views

How would pressing backspace 28 times break Grub2 [duplicate]

I just came across this article about how pressing backspace 28 times on the grub screen. Since most mainstream media just says this happens, I've been unable to find anything that explains how it ...
1
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1answer
49 views

How to track who added sudo privilege to a user

I have a LDAP user named "ciadmin" created on the Red Hat based system without sudo privlidges. Somehow this user now has sudo privileges and can basically become root on the system. I want to track ...
0
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1answer
35 views

Is there any concrete risk involved in using the same password for root, kde wallets and key rings?

To make it easier I decided to use the same password for root (su(do)), kde wallet (KDE desktop) and keyring(s). No one has access to this password in "real world" (given that the computer is ...
3
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1answer
24 views

Monitoring ports on ongoing connections

I have a vps server that is blocking me every hour via ip with its firewall. Looking the logs several messages like these where found: Dec 16 13:52:08 srv kernel: [17226167.610181] Firewall: ...
0
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2answers
81 views

set up secure connection over SSH

I'm setting up a server application which requires to establish a secure connection over SSH2, e.g. a client must open SSH2 connection to the server to reach specific application: % ssh -s -p5000 my....
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0answers
21 views

Benefit of using multiple checksums for a group in AIDE

What are the benefits to having all md checksum functions specified for a group when running AIDE? For example, what is the difference between defining the first line and the second line with less md ...
0
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1answer
69 views

ARP Spoofing in Data Center

I have a dedicated root server. I noticed strange connections from 255.255.255.255 in iftop. Because of that i tried to investigate it. I runned the following command: tcpdump -i eth0 ether ...
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0answers
181 views

Block IP Fragmentation attack using iptables

I am trying to stop all MF flag packet which has more fragment big set. because i have seen many IP Frag attack taking advantage of it. I know its not a good idea to do but, I have test my application ...
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0answers
16 views

How can I encrypt disks in Mint-17 without destroying the data

I have a mint-17 machine with 2 disks managed through lvm. I would like to encrypt the disks. I need to keep the data/apps intact. Is there a way in mint if I could just encrypt the drives or ...
3
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1answer
86 views

How come I can login to another person's session over vnc just by changing the port number?

I have a user account on a server administered by someone else. I don't have root access. The server is CentOS 7. I couldn't connect over vnc on the usual port I use, so I ssh'd into the server and ...
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0answers
33 views

When have software mirrors been compromised before?

Stemming from this answer Mirrors can be compromised (this has happened in the past). It's easier to watch a single distribution point. If an attacker managed to upload a malicious package ...
0
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1answer
463 views

Help With PulledPork Please

I have been working to get snort, barnyard2 and pulledpork installed on my Ubuntu machine, and I have the 1st two installed not problem. With pulledpork I cant seem to get past this error message: ...
0
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2answers
75 views

Is UFW behind a firewall(ed) gateway router necessary

Is it really necessary to run UFW behind my Gateway Router which already has Firewall/Port rules? In this example, I am discussing running UFW on an Internet Accessible (Linux) Server that is behind ...
0
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1answer
25 views

Value of nmap option

I've found in some docs of port knocking, that it is used the option --host-timeout I don't understand why is 201 assigned to it? e.g.: nmap -Pn --host-timeout 201 --max-retries 0 -p 7000 192.168.80....
15
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1answer
327 views

Why does ArchLinux keep some users/groups after package uninstallation?

I've noticed that after uninstalling the postgresql package in ArchLinux the postgres user and group are not removed automatically. The same is true for some other packages. Investigating this further,...
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2answers
257 views

What kind of data is stored in the ext4 file system's journal?

The ext4 file system has a feature called has_journal. In the dumpe2fs output, we can see something like this: # dumpe2fs /dev/sda2 | grep -i journal Journal inode: 8 Journal backup: ...
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0answers
12 views

Folder Permission on Storage Mounted by User [duplicate]

I'm having trouble with an external hdd. Let us say there're two users; user, guest. Let the external storage be called hdde. User has automagically mounted hdde in Ubuntu (for some reason it's /media/...
0
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1answer
105 views

How do I bind webmin to the 127.0.0.1 address?

How do I bind webmin to the localhost address? I'd like to be able to do this so that I can secure all the admin services on my TurnKey Linux machine by binding all of them to the localhost address ...
1
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2answers
53 views

Symbolic link in the form of user@hostname.6912:144780xxxx

I just noticed a symbolic link named .#tmp.tmp# in my home directory (not created by me) and it pointed to user@hostname.6912:177780xxxx where the x's are additional numbers. A google search revealed ...
2
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1answer
105 views

Replace Firewalld with system-config-firewall-tui on CentOS 7

I have a question regarding firewall config on CentOS 7. What I have done Disabled firewalld with systemctl stop firewalld.service Installed and configured system-config-firewall-tui Tested my ...
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2answers
41 views

How is OpenSSH sftp jail/chroot working?

This question is actually too broad... What I really want to know is whether or not it actually chroots and, if so, how a SSH user deamon[1] can be launched in that jail in spite of the obvious lack ...
15
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1answer
917 views

Why can I list other users processes without root permission?

Using ps -aux or top, I can list other users running processes, but i'm neither running as root or making use of sudo, why ?
4
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2answers
442 views

Can users in a group access a file that is in another user's home directory?

I have 3 users A,B and C inside a group 'admin'. I have another user 'D' in whose home directory, there is a project folder. I have made D as the owner of that folder and assigned 'admin' as the group ...
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2answers
433 views

Editing my /etc/hosts.deny

I'm being trolled by China, and don't know why I can't block their request to my server. //host.deny ALL: item.taobao.com ALL: 117.25.128.* But when I watch the error log on my webserver tail -f /...
2
votes
1answer
84 views

Is it possible somehow to tell if a laptop is moved in a bash or python script?

I'm trying to figure out if there's a way to use a bash or python script to tell if my laptop gets moved. I had the idea of using wifi signal strength to do it, but the problem with that is that you ...
0
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2answers
93 views

How block all request as ServerIP:Port by iptables

I see many http ddos requests to my server as serverIP:80. Its possible to block all incoming requests to myServerIP:Port?
1
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1answer
75 views

Connect to WiFi without storing password (Raspbian)

I notice WPA_GUI has saved my WiFi password to /etc/wpa_supplicant/wpa_supplicant.conf. The unit I'm trying to set up is a shared use system on enterprise WiFi that logs on with a user's account, so ...
3
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0answers
41 views

Automated kernel recompilation on security patches?

I'm on Ubuntu 14.04 and really enjoy the fact that I get automatic kernel security updates. When a kernel security problem is patched, a new package will be shipped with the new version. My machine is ...
2
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0answers
34 views

Microkernel (e.g. GNU Hurd) more secure than monolithic kernel (Linux)? [duplicate]

I would like to understand (in relatively layman's terms) if and how a microkernel such as the Mach-based GNU Hurd is more secure than a monolithic kernel such a Linux. Additionally, does a micro-...
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3answers
94 views

Audit simultaneous logins in AIX

We are in a banking enviornment and our core system is based on AIX. Multiple users are logging in with the same userID at the same time using SSH. I know I can see who SSHed into the system from ...
2
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1answer
343 views

modsecurity rule for blocking wordpress / joomla admin login - others

I have an old rule for ModSecurity 1.x to block admin brute force attacks, and only allow them in the internal network. When I migrated to 2.x, it stopped working. Also the networking ipmatch rules ...
2
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1answer
69 views

Should I generate the SSH key pair to give temp access to someone, or accept their public key?

I want to give an external user temporary SSH access.. Should I generate the key-pair and securely give them the private key. Or should I accept their public key. ? Advantages of the first ...
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2answers
191 views

reset system file permissions, owners and groups

Mac has a utility that checks permissions of files installed on your system to make sure they have the correct permissions as per an installation. Is there something like that with LinuxMint. I am not ...
0
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1answer
68 views

Procedure to analyse if a process is hacked/cracked

By a pure casualty, I discovered that a process is taking 100% of one core sometimes when I am away of my computer: When using the CPU, it is below 1%, but when the computer is IDL, meaning the screen ...
1
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1answer
46 views

Is there anything important in /var? [closed]

Is there anything important in /var/ such that if something gets corrupted/deleted, it would break the system?