Tagged Questions

Securing Linux systems and applications; understanding Linux security features.

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4
votes
2answers
245 views

Erasing encryption (LUKS) keys before suspend-to-RAM?

I recently had been wondering if there is a way to erase my LUKS keys from RAM before I suspend my device (usually a laptop) to S3 mode. I am interested in a solution that would work for my / ...
1
vote
1answer
249 views

How do I find out if I'm connecting to a spoofed server after getting “The authenticity of host [hostname] can't be estabilished”?

I've been SSHing into my VPS for months with no problems and this morning it returned this familiar message: The authenticity of host '[hostname]' can't be established. ECDSA key fingerprint is ...
2
votes
0answers
1k views

What is a self-contained cross-platform encryption for USB drive? [closed]

I'm trying to find self-contained encryption solution for USB drives while at the same time being platform independent. For example, Windows' BitLocker only works on Windows and not on OS X or Linux. ...
1
vote
1answer
81 views

What are good ways to check for tampering/bad behaviour on a linux server that has already been set up but it's your first time logging into it

For this I am assuming we have a server that is of a client or a friend, so we the helper are not innately familiar with exactly how things should be be. What are good commands and ways to check to ...
1
vote
1answer
143 views

how to continuously caputre all my network traffic? [closed]

I've got a Linux desktop that will be a gateway between my private network and the open internet. I'd like it to capture and store all network traffic passing through it continuously, 24/7 (until the ...
0
votes
2answers
222 views

Does iptables work in kernel mode? [closed]

I am not sure about that. It should run in kernel mode in order to avoid some user-mode program to kill/suspend the firewall and do its dirty job. The malware would not be able to kill the firewall ...
20
votes
2answers
2k 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
261 views

How to measure the integrity of the OS (Linux)?

I am working on a project which requires Integrity measurement of OS (Linux). One way to do that is using IMA but I am not sure if it fits in the scenario below. The scenario of the project is some ...
1
vote
2answers
92 views

PHP Handlers and Caching

I recently began configuring our production server for a new Drupal site. Up till now, I've always used the default PHP handler mod_php, and removed write privileges for any directory/file except ...
1
vote
3answers
171 views

Cracking passwords after a patteren with ex. 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 patteren. ...
15
votes
1answer
481 views

Keyboard firmware hack - Linux vulnerable?

I see that Apple patched OS X to mitigate against K. Chen's famous Apple keyboard firmware hack. However: Apple keyboards can be used with computers running other operating systems; and in any ...
3
votes
0answers
101 views

Deny Skype video access in Linux? [closed]

I have noticed that despite having configured Skype to not access video, during startups it continues to access the webcam momentarily. Skype is not a user, so I am unsure how to modify its ...
0
votes
1answer
243 views

Installed new Wildcard certificates on my server, but still appear as expired on browser [closed]

I have bought new WILDCARD certificates (*.mydomain.com) for my servers. I was able to install successfully on one server. So, I know the files are correct and I was able to verify their validity. ...
2
votes
1answer
289 views

For remotely unlocking LUKS volumes via SSH, how can I verify integrity before sending passphrase?

Although this is closely related to the recently closed question Evil maids in the server room [closed], I believe that it's more answerable. I'd like to unlock LUKS volumes on remotely hosted ...
2
votes
1answer
123 views

Should the root Unix user have a shell?

I usually use Debian-derivative distributions such as Ubuntu server. Most of them come pre-configured to use sudo rather than su and to prevent access to the root account at all possible. With this ...
1
vote
3answers
390 views

Best practice for accessing management port of firewall

I'm in the process of setting up a bunch of servers at the other end of the world (well, 8 hours travel time) in a co-location place. The servers and firewall all have a remote management port (KVM, ...
0
votes
1answer
249 views

Read-Only USB thumb as Linux boot encryption authentication [closed]

I would like to have a physical key to decrypt Linux machines at boot. This is just an idea and I would like to know if there are already projects or established methods to achieve this. Let me ...
1
vote
1answer
305 views

Installing Joomla with nobody:nobody user/group (CentOS/cPanel)

If you are installing Joomla via cPanel's File Manager to your mywebsite.com (user mywebsite) account, you will upload the package to your server and extract the archive. All files will have the user ...
0
votes
3answers
225 views

How to store user credentials like Mint.com [duplicate]

If you have a website that need to store user's credentials for other sites, how do you store those credentials securely? An example is Mint.com where you give them your username/password for your ...
1
vote
2answers
232 views

PCI Compliance Distibution

I run a small e-commerce website hosted on a dedicated server with Debian 6 Squeeze. I need to become PCI compliant (the card industry standard for security). Therefore I have registered with ...
2
votes
1answer
199 views

Evil maids in the server room [closed]

I am well aware of the fact that physical insecurity in principle means no security. But let´s say I own a root server with full disk encryption which is unlocked/booted via dropbear ssh. In which ...
0
votes
3answers
2k views

What is the hack attempt going on when I see: did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA

When I look at my sendmail logs, by far the most common "error" I see is the following: Nov 22 16:49:50 MyHostname sendmail[18832]: rAMMnj2u018832: [IP address redacted to hide the guilty] did not ...
-2
votes
2answers
24k views

backtrack or kali linux ??? Which is best for a beginner pen tester ? [closed]

I am using backtrack right now but i also wish to switch to kali linux if its more interactive. Because i am just a beginner pen tester. I tried with both bt4 and bt5, but novice in kali linux.
11
votes
4answers
3k views

How secure is NOPASSWD in passwordless sudo mode?

On all our boxes we have ssh access via keys. All keys are password protected. At this moment the sudo mode is not passwordless. Because the number of VMs are growing in our setup, we investigate the ...
0
votes
1answer
112 views

Strange Virus Infecting My Server

I am currently working on a Web App on my dedicated server (LAMP) and it seems like it might be infected with some strange malware/virus of some kind. When I access some domains on that server (every ...
3
votes
3answers
2k views

How Tor, Privoxy, Vidalia and Polipo are getting together?

I realized that these applications are frequently used together. What is the role of each software in the mission of anonymity and privacy on the web? While I understand Vidalia is a GUI provider, I ...
1
vote
0answers
101 views

What are some good design practices for cross-platform certificate storage?

Question from the Bouncy Castle development list: At present we use the Windows certificate store as: var store = new X509Store(StoreName.My, StoreLocation.LocalMachine); ...
3
votes
2answers
320 views

Disable local/KVM access on a Linux VPS (allow only SSH)

Friends of mine have previously had issues with VPS security. The security was no fault of the operating system/services themselves, but mainly due to the "Control Panel" that gets forced upon you ...
0
votes
5answers
4k views

Can I use Kali Linux when I learn Backtrack well?

I'm new to security issues and I'm almost buying a course at ELearningSec(begginners course,of course), I will in a company and want to learn about offensive and defensive skills to improve the ...
0
votes
1answer
211 views

Fishy: VMware sends all traffic through akamai

I'm running Linux inside of VMware on the Mac, and on Linux I'm running a program that has connections open to perhaps 4 different machines. On the OS/X side however VMware has only 1 active network ...
0
votes
1answer
485 views

Exploit Compilation Problem [closed]

I am trying to compile the following exploit: http://www.exploit-db.com/exploits/10613/ But get the following error: local.c:12:22: fatal error: asm/page.h: No such file or directory compilation ...
7
votes
2answers
218 views

What output can a program, when executed from a command line, output to generate behavior that is a vulnerability on the terminal emulator?

Reading this post, titled "Fixing Unix/Linux/POSIX filenames", I came across a VERY interesting phrase by the author, which says: Oh, and don’t display filenames. Filenames could contain control ...
6
votes
4answers
595 views

Security of different OS

At my work we are given a computer to set up at home so if we ever feel like working from home we can do so. The thing is that whenever it comes to developing for java I always prefer using windows or ...
0
votes
2answers
477 views

Disabling SMEP on x86_64

I have recently been doing some research into kernel exploitation on X86_64. A problem I have run into is that I have found Intel's SMEP to be killing my contrived example of a kernel NULL pointer ...
43
votes
5answers
3k views

What does Mark Shuttleworth mean by “we have root”?

In a blog post in response to the Amazon privacy controversy, Mark Shuttleworth wrote: Don’t trust us? Erm, we have root. You do trust us with your data already. You trust us not to screw up on ...
4
votes
3answers
158 views

How can you know what is distributed with your Linux

I'm curious, in theory, how can one know if for example kernel that is distributed with Ubuntu Linux is really what is on https://github.com/torvalds/linux and not some modified kernel which contains ...
15
votes
7answers
1k views

Defence Against Keyboard Keylogger

I am wondering whether there is a way to defend against USB Keyboard Keylogger (obviously other than physically checking the keyboard every time after leaving my computer unattended). These days, ...
0
votes
1answer
580 views

Stack Guard vs Stack Shield

I would like to know why nowadays Stack Guard is used everywhere (example: ProPolice in GCC, /GS in Visual Studio), instead of Stack Shield. Both the approaches (i.e. Stack Guard & Stack Shield) ...
6
votes
4answers
1k views

Security of the KWallet password encrypting application?

According to http://gaganpreet.in/blog/2013/07/24/kwallet-security-analysis/ , the KWallet password management system is quite weak, it uses key splitting, Blowfish 56, and no salt. The key ...
-1
votes
2answers
149 views

Linux: Blocking outside attempts at attacking computer

in the past when I wanted to block outsiders from attempting to start connections with my Linux machine's various TCP services, what I was told to do was to add this line to /etc/hosts.deny: ...
0
votes
2answers
279 views

Isolating host machine from external network

How to prevent a host machine from sending/receiving packets with the following network configuration: eth0 - physical NIC :: not configured; tun0 - virtual NIC for VM which role is the gateway for ...
1
vote
3answers
603 views

What is the most secure way to set up web server user permissions? [closed]

The default Debian way of setting up a common web server (Nginx) is to run the main process as root and unprivileged workers as www-data. In order to allow for the worker processes to read/execute web ...
2
votes
3answers
388 views

Is there an internal equivalent to fail2ban?

fail2ban is a protection against brute-force that locks a user out after a definable maximum failed login-attempts. But if a user already has access to a server with another username already fail2ban ...
6
votes
2answers
3k views

Best way to allow sudo access when using ssh keys

Probably a simple question, but I can't seem to find any actual best practices out there. I manage a handful of servers and I am really getting sick of tracking my passwords in pwsafe. I've been ...
1
vote
0answers
161 views

Tools to perform benchmark of block/stream ciphers on Linux? [closed]

I would like to perform some benchmarking of different block and stream ciphers for general data (lossless and lossy data) encryption and decryption (with focus on power consumption). To get general ...
-1
votes
1answer
598 views

Afraid about SSH on my Linux system

I've checked my Linux server (Centos 6) with rkhunter. I found the following in rkhunter log [14:38:54] Checking if SSH protocol v1 is allowed [ Warning ] [14:38:54] Warning: The SSH ...
1
vote
1answer
224 views

SSH authorized_keys

Can you correct me on this. I create a keypair on my PC. Copy the public key (append to authorized_keys) on the server. Disable password auth on the server, and SSH to server from my PC. I have ...
1
vote
1answer
81 views

Securing WebHosting Shell Access

If I provide SSH access to users who has paid webhosting service, what security measures should be applied ? What I can think of: SSH keys RSA of 4096 size (shall be secure for a while) Apache ...
5
votes
1answer
127 views

How is using acces() opening a security hole?

The man page for access(2) tells : Warning: Using access() to check if a user is authorized to, for example, open a file before actually doing so using open(2) creates a security hole, because the ...
3
votes
3answers
2k views

Alternative to AirPcap for Linux?

I need to sniff WiFi packets, but according to AirPcap FAQ page, it just supports Microsoft Windows, not other platforms. Does any alternative of this product work in Linux? Please don't offer Alfa ...