Securing Linux systems and applications; understanding Linux security features.

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1answer
67 views

security updates for embedded firmware Tomato (router) [closed]

I installed on my Linksys router Tomato firmware. I saw and now don't understand how security updates work. It can't be that there is no vulnerability since 2010. Tomato Firmware v1.28.1816 ...
0
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1answer
142 views

Is BSD more secure than GNU/Linux? [closed]

BSD controls the OS while Linux is just a kernel. BSD is less popular than Linux, but which one is better in terms of security?
3
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1answer
64 views

IPSEC End to End Tunnel Throughput

I have established a IPSEC tunnel ( standard configuration , with ESP) , on two Linux machines (centos6 , core i7) communicating over 1 gbps LAN , and i'am checking the communication throughput. It ...
5
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2answers
121 views

Securely decommissioning a dedicated server

One of my dedicated hosting CentOS servers hit 12 years. I received an end-of-life notice on it, and I started receiving SMART errors as well. I guess it's time to let it go. But before I do, I'd like ...
0
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1answer
57 views

Test the security of my Linux setup [closed]

I have a Ubuntu installation running in VirtualBox. I have made a few modifications to it (some kernel modules and startup scripts) that I hope would make it very secure. Is there anyway I can test ...
4
votes
2answers
226 views

How do shared hosts protect different sites?

I host all my websites from a single VPN, and am about to sell some limited space of my Linode to a friend to host their new blog. It'll simply be another entry in Apache, and then a dedicated folder ...
21
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5answers
4k views

environment variable accessibility in Linux

Perhaps this is a trivial question, but how accessible are environment variables in Linux between different users? e.g. if Alice executes export FAVORITE_FOOD=`cat /home/alice/fav_food.txt` Can ...
4
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1answer
59 views

Protect sensitive information in a password-free, shared database

I'm working on a webserver that stores resources in Redis. To make swarm-deployments as hassle-free as possible, I'm implementing an option where the server doesn't need to access the filesystem to ...
4
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1answer
140 views

Mitm attack problem [closed]

I have a problem with implementing this attack. I have a kali linux machine on vmware workstation. My router is - 192.168.1.1 My victim ip is - 192.168.1.254 arpspoof -i eth0 -t 192.168.1.1 ...
3
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0answers
58 views

Practicing with return-2-libc exploits

I am trying to reproduce a return-to-libc for a simple vulnerable program. The tutorial is taken from https://sploitfun.wordpress.com/2015/05/08/bypassing-nx-bit-using-chained-return-to-libc/ I made ...
42
votes
2answers
6k views

What is happening now with the Grub backspace key security vulnerability?

I have just read an article about a new Grub vulnerability. The article said that you can bypass the password protection by pressing backspace about twenty eight times. I am a security guy and I am ...
0
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1answer
1k views

mprotect at kernel level

What would happen if a kernel-level process sets some of its memory pages as PROT_NONE with mprotect and another kernel-level process tries to read one of these protected pages? What is the ...
2
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2answers
390 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 ...
65
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6answers
36k views

Should I get an antivirus for Ubuntu?

Considering the recent thread regarding anti-virus for the Mac I wonder how many of the arguments put forth are relevant today to Linux systems, specifically Ubuntu. There are no known Ubuntu ...
5
votes
2answers
102 views

Can malicious software be installed inside Linux swap partition?

Is it possible for a virus of any kind to be installed inside Linux swap partition? If so, could it be transferred to the system even after formatting the Linux partition only and reinstalling the OS ...
3
votes
1answer
103 views

Laptops SSD: Hardware Encryption plus DM-Crypt/Luks - Security and Performance

I just bought a new Thinkpad t450s, and put a Samsung 850 pro in it. My Cpu supports AES-NI and the SSD supports hard-ware based encryption. My question is, is there any reason to do Both ...
6
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1answer
547 views

How to detect malicious code sending information to attacker's server in linux

Suppose you have some malicious code on your linux laptop, for example a rootkit or trojan or something like that. Now restrict your attention to the case that the malicious code does transfer some ...
-4
votes
1answer
156 views

What is the most secure mobile os? Ubuntu? [closed]

What's the most secure mobile os for the average day to day user concerned with protecting online banking, personal data, photos etc? And is the new Ubuntu mobile os likely to have the same security ...
5
votes
2answers
1k views

Can you describe a real-life scenario of exploiting sticky bits?

Sticky bit are mentioned in every UNIX security book, but I couldn't find anyone that describes the exploitation of Sticky Bit set on a file. Can you?
1
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2answers
114 views

Are there any security benefits in deleting the private key of a https webserver after starting it?

Say you have a web server offering pages via HTTPS. After the process begins running, if you were to delete the private key, would this prevent private key recovery in case of server compromise? ...
1
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0answers
158 views

IPtables accepting SMTP without being configured?

While setting up the IPtables rules for a new server, I set up Postfix and send an email to try it out. To my surprise the email arrived without me declaring a rule for the port in IPtables. ...
5
votes
2answers
126 views

Is it possible become root through a broken symlink owned by root and globally writeable?

I'm looking for a vulnerability on a server. I'm looking in the /var directory and I get something like this: drwxr-xr-x 3 root root 4.0K Aug 14 21:02 kerberos drwxr-xr-x 12 root root 4.0K Nov 11 ...
1
vote
1answer
121 views

Strange SECCOMP entries for sshd in audit log

I've posted this over at ServerFault but haven't received a response over there. I'm not a security professional, but I'm curious as to what kind of attack this might be and how the attackers might be ...
5
votes
1answer
104 views

How to grant permission to read a text file to a specific application run by a regular user?

A text file is situated in /opt/somefolder. It contains a pair login - password read by an application when authenticating on a server. The application is run by a regular user, so that the file can ...
0
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4answers
418 views

How can I use netcat like ping?

How can we use the netcat (nc) to determine whether a particular machine is running web, mail or SSH services?
3
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0answers
41 views

Address of environment variable different for each directory

I'm writing a return-to-libc attack for a school project. My script retrieves the system(), exit() and shell addresses as follows (it's a sh script that calls some c programs): Create the environment ...
7
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1answer
77 views

Impact of using a NON-SSL/TLS connection for API calls on same server

I have two domains hosted on the same server, Domain A and Domain B, both domains have different IP addresses, assuming IPs 1.1.1.1 for Domain A, and 2.2.2.2 for Domain B. Each domain has a different ...
3
votes
2answers
136 views

Is using Chrome and Tor Browser at the same time secure?

I question this recently because as I was using the Tor Browser, while in the same time my Google-Chrome was opened, and I right-clicked on a word to search it in 'Disconect', when the page loaded I ...
29
votes
4answers
3k views

Can the root user be removed from a *nix system to prevent privilege-escalation?

Once a *nix system is properly configured and hardened, is it a conceivable strategy to remove all super user/root users? Are there benefits to removing root from a system altogether to prevent ...
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0answers
40 views

Under which circumstances is the default security profile of XRDP considered okay?

In xrdp.ini, the base install of xrdp on my raspberry pi*, there I have the following below. I changed crypt_level to high. [globals] bitmap_cache=yes bitmap_compression=yes port=3389 ...
0
votes
1answer
56 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 ...
11
votes
7answers
1k views

How are open-sourced operating systems and software kept secure?

I have been wondering about his for awhile. I have Linux running on a PC at home. I had a jailbroken iPhone. They both have attributes that make them very attractive, and they are also FREE! But I ...
5
votes
1answer
156 views

VM production server and low entropy

I'm monitoring a VM functioning as our production server. I noticed it has at many times, quite low entropy (/proc/sys/kernel/random/entropy_avail). On average our server(which among other stuff does ...
3
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1answer
45 views

Prevent snapshots of VPS

Pretend I have a server. Is there anyway to prevent (or make more difficult) the administrator from taking snapshots? Feel free to give me a software way, or suggest if I should change server types; ...
3
votes
2answers
162 views

Decoding injected PHP malicious code in my server

I've found on internet similar issues, and I compared the code. This one is different. I recently found out that the CentOS LAMP webserver we use for development in our office was infected by a piece ...
2
votes
1answer
103 views

Linux antivirus and files bigger then 4GB

I wish to scan files that are bigger then 4GB. For example video files. I noticed many antivirus software are limited to a maximum of 4GB (ClamAV for example). So: Is there a antivirus software ...
4
votes
1answer
45 views

Is protecting a parent folder secure enough to protect files within that folder?

So this topic came up during a hardening exercise on Unix/Linux machines where a parent folder was marked with chmod 740 but files within that folder were marked chmod 644, and the argument went that ...
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1answer
94 views

Understanding HTTP response from Linux Server

I am working through a question that involves someone using a vulnerability in a Linux server in order to gain access to it. The first part of the question states In monitoring the network activity ...
0
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2answers
94 views

Is there a tool to detect what technologies a website uses? [closed]

I'm looking for the name of a tool I've used a long time ago, that for a given URL/website address would extract the technologies used for that site. For example that the site is running Apache, using ...
1
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2answers
87 views

Ettercap Remote Poisoning

I have a question about one parameter and that's it. When I'm doing DNS spoofing I have to use arp:remote. Can someone explain to me what arp:remote means? I read the man page, but did not ...
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1answer
61 views

Hydra saying cracking done and displaying random passwords

I have Hydra on my Linux machine. I want to test cracking security with Hydra on SMTP but I get no success. After about 20 messages that SMTP mechanism and a random message like [465][smtp] host: ...
1
vote
1answer
162 views

Can a root user inside a Docker/LXC break the security of the whole system?

My question is probably more about the LXC than about Docker, but I wonder what are the security mechanisms to prevent a root user inside a Docker image to access the whole host. More precisely, I ...
3
votes
3answers
205 views

What should I be aware of when opening my home server to the internet?

I've built a home server (pretty much just a basic PC with a couple of big HDDs) which I would like to use as an FTP server and a minecraft server. Both would be for members of my gaming community. I ...
0
votes
0answers
8 views

How to prevent future attacks from Trojan.Agent.Linux.A? [duplicate]

One of our servers was just infected by Trojan.Agent.Linux.A (see https://www.virustotal.com/en/file/ca22002822b27562971b1b12bfd61f2f670554ebdb0907270fda4a65f7fd2eed/analysis/1448647113/). I am ...
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votes
2answers
160 views

How to limit source port for accessing blocked website?

My country has a firewall which blocks sites like Facebook, whatsApp etc. However, they use some kind of port blocking, so some important websites for me like Chegg is also getting blocked I think due ...
3
votes
4answers
219 views

How Likely Is It For A Virus To Spread From A Linux VM To The Windows Host

I'm currently running Windows 10, and I plan to use a Linux distro to run in a VM (Virtual Box). I know Linux is one of the most secure operating systems there is and I'm curious as to how likely it ...
1
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2answers
469 views

linux hidden OS

I have been reading about hidden volume OS with truecrypt, and now with its successor, VeraCrypt. https://veracrypt.codeplex.com/wikipage?title=VeraCrypt%20Hidden%20Operating%20System But Couldn't ...
7
votes
2answers
257 views

Prevent ARP spoofing with dynamic static entry on Linux

ARP spoofing detection/prevention seems to be quite popular here. With other techniques like port stealing aside, I'm wondering if the following could work to prevent it: Whenever my Linux ...
0
votes
2answers
10k views

Hydra https-form-post [closed]

I have never experimented much with online password crackers. I attempted to use Hydra today on this website www.athena2.harker.org and I keep getting false positives. This is what I have done so ...
1
vote
1answer
516 views

ClamAV Flagging application .swf files as malware

ClamAV scans on our application servers are identifying some of our legitimate Flex .swf files as malicious, specifically citing CVE-2015-5548 (specifically, "Swf.Exploit.CVE_2015_5548 FOUND"). ...