Securing Linux systems and applications; understanding Linux security features.

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Is this a secure way to connect with Tor?

I was discussing the use of tor with a friend, and he happened to suggest a way to remain secure when using applications on the terminal (Lynx, Nmap etc.) His suggestion was this: ssh-keygen -b 4096 ...
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23 views

How to relay broadcast traffic using ncat?

I have 2 servers, 192.168.1.1 and 192.168.2.1. I want to relay any broadcast traffic (192.168.2.255) through 192.168.2.1 to 192.168.1.1. Here's what I'm doing to relay port 137 traffic, and it seems ...
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26 views

Replay attack on redhat [on hold]

in this case i have a redhat linux that is installed on a virtual machine,I want to change a text file on this machine before it leaves the machine and get to the destination,As i know this known as ...
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32 views

Am I safe to see a thumbnail of a downloaded images on Ubuntu 14.04?

I have downloaded an image that someone has uploaded to my website with a public upload form. My intention was to copy the file in a virtual machine and see the image from there; unfortunately, on ...
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2answers
2k views

Linux password changed. Is this an attack or a hardware glitch?

My Linux (Ubuntu 12.04) password suddenly changed last night and I'm not sure if this is an attack or just a hardware/user error. This is on a personal/non-server box. Several strange events led up to ...
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28 views

IPsec install pluto not finding interface [on hold]

I'm trying to setup ipsec however pluto appears not to bind to a public IP. The error I'm getting is: Sep 18 04:36:45 shiftmy ipsec_setup: Starting Openswan IPsec 2.6.41... Sep 18 04:36:45 shiftmy ...
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3answers
129 views

Are windows users passwords easier to crack than linux?

If i set the same password in both linux and Windows, is it easier for a hacker to break the windows password? If so why and how can i create a windows password in the same security level as Linux?
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1answer
54 views

Linux Rootkit / BIOS Malware: What packages are necessary to get infected?

Everybody knows about the dangers of Rootkits / BIOS malware. What do you say about this countermeasure? In order to actually get infected the malware needs to use the OS to 'patch' the BIOS chip. ...
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2answers
110 views

Receiving sensitive data uploaded on a Web server, and remotely accessing it without exposing it to theft

Edit: I mostly used my university's guidelines on how to meet DPA standards and their own. I extrapolated a bit because encryption on a VM hosted by my uni that is already probably encrypted makes ...
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2answers
27 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. ...
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10 views

Gnome-keyring iteration count location

I know that Gnome-keyring hashes master password between 1000 and 2000 times. It picks random number. I would like to ask where does it save this number, what is the location of that file? As far as I ...
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1answer
74 views

What are the options for acquiring disk image from a Linux computer that can't be removed from a crime scene?

If the suspect's computer is Linux, can you directly use tools such as dd or dcfldd on his computer to acquire the disk image? Or do you need to use forensic live cds like Helix, Penguin sleuth or ...
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3answers
103 views

Not replacing SSL cert on a rebuilt, formerly rooted Unix Server

If a server was rooted, to the point that we know a Perl script which creates a remote shell was placed on the filesystem remotely, and the server was rebuilt entirely, patching the original Apache ...
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2answers
151 views

Where can I “hide” easter eggs for students learning about Linux security?

I feel like this isn't the best place to ask this (since there's no single right answer), but I can't think of a better place. If you have a better recommendation, could you please recommend it and I ...
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0answers
37 views

calculate time taken to reach from network A to B without ping and telnet [migrated]

I want to find distance between A and B either in terms of network time or Hops count.I have few ideas like I can ping B from A will log down time taken to respond that ping request . Also If I know ...
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2answers
25 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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6answers
5k views

Unix execute permission can be easily bypassed. Is it superfluous, or what's the intention behind it?

The unix read permission is actually the same as the execute permission, so if e.g. one process has write access it's also able to execute the same file. This can be done pretty easily:First this ...
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2answers
740 views

I ran a netstat on my server and port 80 is listening, does that mean it is open and vulnerable to attacks? [closed]

Sorry I am just getting into Web Development and trying to learn more about servers and PHP, so I downloaded the LAMP stack on an Ubuntu14 OS and started an apache2 server. tcp6 0 0 :::80 ...
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40 views

CA Flag in SSL certificate [migrated]

I have an web portal running as a POC purpose, and then i have a mobile apps to access this web portal. Since it's a POC, I just generate a self-signed SSL cert and load it inside the Web and my ...
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1answer
25 views

updatedb and encrypted home folders: Does it store unencrypted file and folder names somewhere?

When you encrypt your home folder in Ubuntu and Debian, it protects not only the file contents but also the file and folder names. Yet I see that updatedb and locate works in Debian. When I run ...
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1answer
42 views

How do I secure X server against spyware in a GUI application?

Suppose you have a GUI application, that potentionally may be too curious about your environment, such as the list of window titles. How do I limit application's ability to enumerate windows, capture ...
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1answer
71 views

RHEL 6: PHP 5.3.3 - Is it inherently insecure?

I am talking about the PHP 5.3.3 package that is available in the Red Hat Enterprise Linux repository, running on Apache. From what I can see, as of RHEL 6, it is the latest version (no updates ...
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1answer
53 views

Which hardening methods are used in large linux desktops environments (i.e. Goobuntu)? [closed]

Im courious to know about how these large enterprises secure their linux desktop as Google does with ubuntu LTS. I am the only user at home with linux on the desktop and had already created some ...
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1answer
35 views

Limiting account access based upon NIC used to connect on Linux

I have a server which has multiple NICs (ignoring redundant pairs): 'inward' facing production (connects to other servers); 'outward' external facing production (connects out to the internet via a ...
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1answer
57 views

Linux file information leakage

What information is kept in a linux file about the user and/or system that created it? I want to make some files publicly available, posted on another server such as GitHub or FTP, but I'd rather the ...
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2answers
90 views

Why was LibreSSL PRNG unsafe on Linux?

From the source: https://www.agwa.name/blog/post/libressls_prng_is_unsafe_on_linux The first version of LibreSSL portable, 2.0.0, was released a few days ago (followed soon after by 2.0.1). Despite ...
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3answers
94 views

Is it possible to USB whitelist in Linux?

After watching Black Hat's presentation on the fundamental problems with USB "security", I'm wondering if there's a way to do USB whitelisting in Linux. Is there currently a mechanism that will allow ...
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3answers
66 views

Permissions security scenarios for a web server

Having /var/www/site.com owned by www-data:www-data with a 750 permission for directories and 640 for files, and having my user alexb added to www-data group, I found my self with permission issues ...
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111 views

How do I ensure that my Ubuntu download has not been tampered with?

I am downloading Ubuntu Linux, and would like to make sure that my download has not been tampered with. Ubuntu has a GPG key, which I could use to make sure that the download is valid -- but how do I ...
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3answers
125 views

Is MS Windows more secure than Linux on this aspect?

The administrator account can be renamed which means the hacker needs to figure out two pieces of information : the user name and the password while there is always one root account in Linux named ...
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1answer
37 views

Throttle network based on OS [closed]

What do I need to learn/know to throttle a clients network based on his/her operating system. For example: Someone in my network using Kali Linux... I would like to throttle their traffic to ...
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2answers
67 views

Is it safe to create live usb on an infected system?

I am using Ubuntu 13.10. If my laptop is infected with malware, can I get rid of it by creating a live usb on it and using that live usb format and re-install the ubuntu ? I mean is it possible that ...
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78 views

Does the EICAR test work on Linux based antivirus scanners?

Does the EICAR antivirus test work on antivirus scanners for Linux? The EICAR test is described in more detail here: http://en.wikipedia.org/wiki/EICAR_test_file The reason I ask is that it requests ...
26
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6answers
4k views

Is Linux really that secure, with only root password denying external access?

While I was searching online for information about Linux security, the most typical explanation was: Linux is secure, because the root password is required to access the kernel and install new ...
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3answers
2k 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?
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3answers
2k views

Is it better to use a root password, or use 'sudo bash'?

When I am doing a lot of sudo operations, I like to spawn a bash shell from sudo to make the operations go quicker. I am against assigning a root password because I do not like the root account ...
0
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1answer
56 views

How secure is user-mode Linux, in terms of protecting the host system?

Two questions about User-Mode Linux: Suppose that a privilege escalation attack is used to gain root in a UML guest. Assuming modern (3.0 or later) host and guest kernels, is it trivial to escape ...
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1answer
105 views

Is a Linux environment PCI compliant if the swap file is not encrypted and PANs are loaded into RAM?

Is a Linux environment PCI compliant if the swap partition/file is not encrypted and PANs are loaded into RAM by an application?
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4answers
177 views

DNS spoofing of linux distribution repositories

Question(s) Is it possible to "redirect" linux-update-repos via DNS spoofing (e.g. DNS cache poisoning) to a malicious website, so that harmful software (updates) will be installed, when running the ...
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3answers
259 views

VPS Privacy: OpenVZ vs KVM vs Xen

Considering OpenVZ, KVM and Xen: Which VM technology is the most difficult for the host's administrators to access given an encrypted root partition? Can I have a reasonable expectation that rogue ...
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2answers
68 views

How exactly does this Flash malware function on Ubuntu?

In this video, an experienced Ubuntu user manages to infect his system with some sort of malware. This is the first example I've ever seen of truly successful malware in the wild aside from privilege ...
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1answer
108 views

Ubuntu 12.04 server attacked using Wordpress vulnerability (plugin?) [duplicate]

Env Rackspace cloud server Wordpress 3.9.1 Ubuntu 12.04 Linux web.mydomain.com 3.2.0-67-virtual #101-Ubuntu SMP Tue Jul 15 17:58:37 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux History These may ...
1
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1answer
56 views

Running an Open Server (contents are visible)

I'm considering the possibility of running an Open Server, as I would call it, that is, a server where as much of its contents are publicly visible as possible. I would like to give read access to ...
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3answers
129 views

Help me catch someone red handed on our server.

I first tried to log in this morning and our password was changed on our ubuntu server. I contacted our server support and they told me that I had just been fat fingering the password. I thought it ...
0
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1answer
71 views

What Linux software can I use to explore entropy of a file?

I've heard of tools that could be used to graph entropy of a file. Is there a graphical Linux program that I could use for this job that would let me conveniently explore which blocks of a file have ...
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3answers
131 views

Is there any way to block LD_PRELOAD and LD_LIBRARY_PATH on Linux?

Preferably with a vanilla Linux kernel i.e. not using SELinux or GrSecurity? Lately there has been a case of in-the-wild UNIX server malware: ...
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102 views

the dangers of internet forums - what is FUD, what is not

I just visited a forum and a member knew what OS I was running without me saying anything (a not TOO common distro of linux). Now I'm not sure how he exactly he might have done it, or what information ...
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1answer
68 views

What is a secure mechanism for wireless communication between Android and Ubuntu?

I have come across a few Android apps that provide various features for communicating with a desktop machine (sending text or typing in one direction or another, controlling the desktop pointer with ...
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4answers
3k 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 ...
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2answers
68 views

How to hide or obfuscate the type of OS?

I get the OS type of a remote host by: connecting to an open port (telnet <host> 22); using Nmap (nmap -A <host>). What are techniques and how to hide or change the information about ...