Securing Linux systems and applications; understanding Linux security features.

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Best approach for restricting remote ssh session

Using the following files, I have attempted to restrict the SSH remote login. Having lack of knowledge in linux environment, I don't know the drawbacks and vulnerabilities between the following ways. ...
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364 views

How I can prove that SSH attacks are not from my application?

My ruby on rails web application is hosted on Linode. Linode opened a ticket and blamed my Linode server for attacking other servers. The logs revealed that it's a SSH brute force attack which ...
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Securing USB flash drive on linux

We have a industrial system(running on linux) with a USB port. We have the USB port only for copying certain data. Other than this we don't want the USB drive to contain any other executables or ...
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Securing data on laptop's hdd

I was wondering which is the best way to secure/encrypt data in the hard disk on a laptop that runs Ubuntu Oneiric? Setting LVM encryption? I am mostly concerned about having my laptop lost or what ...
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900 views

Does Fedora 15 still use suid bits?

I heard that Fedora 15 will not use suid bits. Is that true? Is the suid bit a security design bug?
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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 ...
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Pitfalls of SSD encryption

Encrypting an SSD is a process that is sometimes warned should be done with caution. E.g. http://en.gentoo-wiki.com/wiki/DM-Crypt_with_LUKS mentions how the SSD may keep hidden space used for wear ...
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How to secure a dedicated linux server running a LAMP stack for commercial E-commerce use

To be more specific, I would like to get some help, either through a tutorial or through a book, on how to configure an apache server to run securely and minimize the risks for commercial use. ...
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What are the most common files to check with File integrity monitoring software?

I have a file integrity monitoring suite and in it I have to select specific files and folders for it to monitor. There are some obvious services that I want monitored like our web-server. Is there a ...
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379 views

Escalating from Apache shell to root

I have one noob question.I tried to exploit shellshock on my Slackware linux server, but after I connect with reverse shell and User Agent I get that I am apache user and apache user don't have too ...
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Linux forensics questions (ssh config, user activity)

I'm a linux noob and have an assignment I'm a bit stumped on... We're given VirtualBox (vdi) images and raw files for the state of a linux server at 3 different dates. We're supposed to answer: ...
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How can I use nmap to distinguish between a normal linux machine and an android device?

According to this link: here, nmap 5.2 onwards is now supposed to detect android smartphones. I am using nmap 6.01 but it only identifies android devices as running a linux kernel.
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How to scan USB drive with clamav on Linux

Is there a way to scan the entire drive including auto-run and all partitions, including the master boot record (MBR)?
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Wine or sandboxie as sandboxes

I'm looking for a sandbox for Windows. I've looked at sandboxie but I don't know if it delivers what it promises. Is it actually safer to run programs inside sandboxie ? I know a full-blown VM could ...
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3k 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 ...
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791 views

Linux wireless hacking book

I am looking for recommendations on a good wireless hacking book. I would like something more focused towards the defensive, but a healthy knowledge of both would be great. I would also need it to go ...
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How to sandbox Iceweasel (Firefox) on Debian? [closed]

Are there any tools for sandboxing Iceweasel (Firefox) on Debian systems? I'm mostly interested in tools distributed by Debian. (An equally trustworthy source would be second best.) (I suppose that ...
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193 views

Testing a chroot environment for privilege escalation vulnerabilities

I'm looking for holes in my current implementation of a chroot jail that I have implemented for a group of users. Is there anything I can do better here? I utilized the following packages: RHEL6 ...
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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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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 ...
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Are Linux vendor-supplied security updates enough for PCI Compliance?

I have several systems that require PCI compliance, all of them are running CentOS 6.4 with all security updates applied daily. However, PCI compliance scanning will often reject detected versions of ...
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Privilege Escalation Ubuntu

I am trying to learn how an attacker can escalate privileges in Ubuntu 10.04. I have heard that this can be done but no one has ever said how to do it. The best defense is knowing how it is done and ...
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How do I protect myself against the attacks in this php script?

Due to a vulnerability in how PHP was installed (Shared VPS with PHP installed as an Apache module instead of CGI) and hence how OSCommerce was configured (with security of 777 on certain ...
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Is GPG suitable as part of a password manager and generator?

I assume that GPG is very strong to crack, guess, etc. Since I have confidence in GPG, would it be appropriate to use my GPG key as the master key for a password manager or generator?
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How to use VNC with SSH tunnel - “is this howto secure”?

PC-A: the local machine, from where i want to see the remote machine [Fedora] PC-B: the remote machine, where the vnc server will be [Ubuntu] install a vnc client [from where you want to connect] on ...
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How secure is BSD sockets?

BSD sockets API was released in 1983. As it was implemented 3 decades ago and still being widely used, is it secure in today's scenario where every software has to be actively protected against ...
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Pseudo Random Generator is not initialized from the (entropy pool)?

The RHEL5 manuals state that /dev/urandom will use the entropy pool until it's exhausted, and then it will resort to a fall-back pseudo-random algorithm, so that it will never block. But when ...
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Specific Dangers in Joining a Linux Botnet?

Between the PHP-as-cgi-bin problem, and shellshock, I've seen 4 or 5 different Perl scripts that, when run, purport to make your machine part of some scary, heinous botnet. What, specifically, would ...
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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 ...
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Need advice on linux server being hacked

I'm currently trying to find out how one of our centos servers was compromised. We were experiencing malware on our sites. After searching I finally found the malware injecting into the sites. As it ...
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Server monitoring for security

We do a lot of web hosting management and have started to get into selling server management packages. However, we want to start monitoring servers for security related threats. Our clients may use ...
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Can this be a DoS Attack?

When I'm checking my log, I found like 15k events of " PAM service(sshd) ignoring max retries; 6 > 3 " I know this might be normal, and considered as Brute-Force attack, but can it be classified as ...
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How to pass PCI DSS 2.0 anti-virus requirement (5.1) on Linux?

PCI DSS 2.0 Requirement 5.1 states: 5.1 Deploy anti-virus software on all systems commonly affected by malicious software (particularly personal computers and servers). This requirement ...
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Protecting data on a laptop with linux

I'd like to keep some private data (photos, notes, ...) and my browsing data hidden. The rest is not so important. Most of the time I just put the laptop to sleep and don't shut it down often, making ...
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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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possible exploits through avahi daemon

It is always recommended to disable Avahi daemon, for security reasons, when not in use. So, by what ways it is possible to exploit a system which has avahi daemon service running? And how can we ...
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Impact of Mathew Garrett's Secure GRUB Bootloader on UEFI Secure Boot

My eyebrows rose with Matthew Garrett announcing his Secure GRUB Bootloader less than three hours after no longer being a Red Hat employee. This work and its impact on the trust chain design of the ...
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What mechanism enforces user permissions in Unix/Linux?

One of the core pieces of security in Unix/Linux systems is limiting privileges by user. For instance, certain actions can only be done by the root user. In theory, this can keep a malicious process ...
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Detect changes in /boot when using full disk encryption

When running a fully encrypted linux system using dm-crypt, the /boot partition has to be unencrypted to boot, as far as I know. I've setup a server that can be unlocked remotely by connecting to a ...
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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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Fail2Ban does not ban failed root login attempt

I have a small server which only open ports are ssh, http and https. I have fail2ban installed and set up so that after 3 failed attempts someone gets blocked for 10 minutes (thats the dafault I ...
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Does dual boot hurt security?

On my laptop I have a well secured Linux installation that I would like to stay this way. It has in the past and could in the future contain confidential medical data I use for my study. I also have a ...
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You've just acquired a newly created CentOS server, what should you do to secure it?

I've just acquired a new CentOS server, which will be hosting a Ruby on rails application, it is public facing. What should I do to secure this server?
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What are the implications of including binary blobs in the Linux kernel?

According to this there are compelling reasons for caution when installing obfuscated binaries. Knowing this, how can running binary blobs as a part of the Linux kernel be acceptable from a security ...
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Vulnerability testing without the use of exploits?

I was doing some testing on a server to see if it was vulnerable to a 0-day local exploit (the exploit was for gaining root privileges using a bug in the Linux kernel). There was no real information ...
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Exploited by newbie3viLc063s

My debian server got exploited by some scriptiekiddie who used Newbie3viLc063 http://pastebin.com/jma8JRG1 . Scriptkiddie uploaded logo_php.png to my server (My permissions sucked :s) and he did run ...
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What tools can be use for Security Auditing for Redhat

Are there any good tools that can be used for Security auditing of Redhat Linux. That can audit all the critical areas of System and provide the detailed output of all the audited sections.
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Security for home server, wiki

I recently set up my own home server, running Ubuntu linux. The intent I'm having for this is to have a private wiki for my family, so we can have a place to collect information like phone numbers, ...
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Can you have 2 promiscuous (sniffing) ports on a single machine?

I'm wondering if you can actually have 2 (or more) promiscuous (sniffing) ports on a single machine, to monitor multiple network segments? And can you monitor them all with snort?
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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 / ...