Securing Linux systems and applications; understanding Linux security features.

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2answers
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Security of Linux Full Disk Encryption (Ubuntu / Mint) -insecure?

I'm wondering, why is Ubuntu and Mint using SHA1 for Full Disk Encryption? I heard several times that SHA1 shouldn't be used anymore because it is weak and it could be cracked. Could you guys ...
0
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0answers
32 views

Bruteforce with Hydra [duplicate]

I'm trying to use a Hydra script in the following scenario on localhost and Linux: After web form login, my app redirects to another page with header(Location: internalpage.php) I use this syntax ...
89
votes
3answers
15k views

Is a rand from /dev/urandom secure for a login key?

Lets say I want to create a cookie for a user. Would simply generating a 1024 bit string by using /dev/urandom, and checking if it already exists (looping until I get a unique one) suffice? Or should ...
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0answers
89 views

Is there any security risk with adding a **root's** public key to the local user's authorized_keys (so root to login as a user non-interactively?)

Background: I want to try unprivileged lxc containers a try on my small web server (hosting 2-4 users). Since the server is shared among friends, we decided to separate our services from the machine ...
2
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1answer
132 views

Upload a file into directory with public write access

I know it is not right to set a permission for the folder as 777, but if it is done so will it be possible to upload a file into that directory without ftp access ? Here is what I mean Lets say the ...
3
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1answer
174 views

Key generation: Differences between GnuPG classic, stable, modern?

I plan to create a 4096 bit RSA&RSA key pair: gpg --gen-key --personal-digest-preferences SHA512 --cert-digest-algo SHA512 Is there any difference in generated key quality between versions 1.4 ...
3
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2answers
186 views

Firewall egress filtering / quick whitelisting

Suppose your Aunt or Uncle is easily fooled by phishing attempts and their computer has multiple root kits and key loggers running. Assume their computing habits will never change. Looking at his ...
2
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5answers
153 views

Why can't just any program use his own file-system-access-system?

This may sound stupid for everyone who knows more than me about the UNIX-System and security in software: Imagine you have a program trying to cause harm by deleting files. You just do something like ...
3
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2answers
106 views

How to securely install software on Ubuntu?

How to install a software like Sublime Text on Ubuntu 14.04 LTS and mitigate against a MITM attack? There is a PPA available, but the PPA must be added manually. I don't see any PGP keys or MD5 ...
7
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2answers
225 views

List all files with only arbitrary file path read, but no directory listing nor sudo

I have found a path traversal vulnerability that allows me to read any path on the server that does not require sudo. To fully exploit this, I would like to know which files exist in each directory ...
0
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2answers
148 views

Running tails on a corporate computer

Is it safe to run TAILS on a corporate computer? I mean a corporate computer that has hardware cryptography and probably some backdoors; and, by safe, I mean that nobody will be able to recover what ...
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0answers
166 views

Protecting against bad USB in ubuntu

I am referring to this thread: How to prevent BadUSB attacks on linux desktop Since i want to install ubunto onto a possible infected usbDrive using a live DVD and the installation manager i was ...
4
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1answer
5k views

what does it mean to be setuid root?

I am reading Tanenbaum's Modern Operating Systems 3e. He says "Suppose that the program being attacked [with malicious code] is SETUID root in UNIX (or has Administrator power in Windows). The ...
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2answers
375 views

Debian encryption is as safe as Truecrypt. Is this correct?

When I try to install latest debian to my pc, the wizard ask me to input a password to do FDE(full disk encryption). My questions are: What algorithm does Debian use? (Truecrypt = AES) Can I change ...
0
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1answer
39 views

SELinux ignoring /etc/sysconfig/selinux directive

I'm running SELinux on CentOS 6.5. In /etc/sysconfig/selinux I have set SELINUX=permissive. But everytime the system starts, sudo getenforce shows SELinux as Enforcing. What could be causing it to go ...
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1answer
291 views

ARP: Forwarding or dropping with IPTABLES

So, I ve been trying to ARP Poison my home computer and router (Intended to learn and discover the networks bahaviour). And with success. The whole time I ve been using: with ...
0
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2answers
153 views

Is openVZ patched against all exploits for its current kernel version?

I am looking for a container vitalization software that will allow me to create containers that will house specific software/jobs/tasks which I can start stop at will (and bind to interface aliases). ...
3
votes
2answers
284 views

LUKS nuke efficiency

I am wondering about LUKS nuke patch efficiency. In fact, I think I don't really understand it. From what I know of LUKS, a passphrase is used to encrypt a random key (the master key), which is used ...
0
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2answers
3k views

Exploit failed [unreachable]: Rex::ConnectionTimeout The connection timed out(remote host ip)

I keep getting this when I start to exploit, trying to exploit my xp machine but this keeps happening, I can not find the fix anywhere, I don't believe I am the only one getting this.. I am a ...
0
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0answers
71 views

Secure password transfer from stdout to another window

I am currently trying to build a little, secure password manager. As of now, I've implemented the encryption. Each website has its own file and each file has a number of fields (Most commonly username ...
1
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3answers
374 views

Cracking passwords after a pattern with John

So I am trying to find out how easy it is to crack a password using some great Linux tools. We all know about John as a password cracker and how great it is. But how about specifying a pattern. ...
9
votes
1answer
113 views

Security measures and anti-virus on server to mitigate acting as a propagation vector

We have a web application for which I've been asked to add the ability to let users upload documents that will then be visible and downloadable by other users. Those documents will typically be images ...
4
votes
1answer
159 views

Is Linux's 'W' command a security breach?

I was surprised that the out of the box 'W' command on Linux provides so much information without needing any SUDO or admin permissions. In particular, the command shows the command line of each ...
3
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2answers
71 views

Copy Metasploit from Linux to Mac OSX? [closed]

I'm just wondering is there anyway to move Metasploit framework from Linux to Mac completely and It will be work ? and if yes , how ?
7
votes
5answers
2k views

Fastest way to “lockdown” CentOS and have network intrusion detection, firewall, etc up and running?

Are there any proven concepts or "installers" to get up and running based on the best practices securing and locking down a CentOS installation? I'm hoping for an automated tool that would scan the ...
2
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2answers
77 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 ...
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0answers
136 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
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2answers
104 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 ...
12
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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.
9
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2answers
10k 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 ...
11
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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
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2answers
53 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
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1answer
6k 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
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1answer
810 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
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0answers
85 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
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1answer
114 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
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0answers
36 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 ...
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2answers
133 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
95 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
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0answers
168 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
306 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
172 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 ...
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1answer
112 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
121 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
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1answer
122 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
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1answer
183 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
257 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
66 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-- ...