Securing Linux systems and applications; understanding Linux security features.

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15
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6answers
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Convenient cross-platform help on checking secure hashes like SHA-256

It is often helpful to be able to obtain a good cryptographic checksum of a file, e.g. the SHA-256 hash. This can be used to verify file integrity, so long as you have a reliable source for the hash. ...
2
votes
5answers
143 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
votes
2answers
85 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
votes
2answers
197 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
113 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 ...
0
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0answers
122 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
votes
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 ...
1
vote
2answers
296 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
31 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 ...
-1
votes
1answer
227 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
votes
2answers
118 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
194 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
2k 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
votes
0answers
67 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
vote
3answers
339 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. ...
1
vote
1answer
49 views

Security implication of non-free drivers

I was wondering what the security implications are of using non-free drivers on a linux laptop. Especially for graphics and wifi.
9
votes
1answer
97 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
153 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
votes
2answers
61 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
votes
2answers
75 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
93 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
91 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
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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
votes
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
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
5k 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
776 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
78 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
97 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
35 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
113 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
83 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
119 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
232 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
136 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
100 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
91 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
118 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
142 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
180 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
59 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
70 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
92 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
952 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
74 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 ...