Content related to computer security., i.e. content about policies, mechanisms, etc. needed make sure data is not leaked or corrupted and services available in all circumstances.

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4
votes
2answers
162 views

Finding the logs in a hacked server. [closed]

My server has been hacked and the hacker managed to ssh as root (I know, horrible mistake on my part). What files should I be looking for to discover the origin of the attack? (At least their IP). ...
2
votes
3answers
97 views

How do I disable and re-enable Java whenever I want?

For me Java is just a security threat. Not many legitimate Linux apps use Java. However there is an abundance in Java malware and malicious remote administration tools like Jrat among others. But one ...
1
vote
2answers
161 views

How is the loopback device traffic allowed?

How can I allow the traffic to be sent on the loopback device (lo)? What is the iptables command for it?
0
votes
1answer
347 views

iptables couldn't load target allow

I am using the command below to allow all traffic from hosts on my internal network but it says "iptables v1.4.18: Couldn't load target `ALLOW':No such file or directory". What is the problem here? ...
5
votes
1answer
34 views

Need More Information About KDE Job Notification

I installed Debian 7.2 on a new laptop a couple of days ago, and now I'm getting a strange job notification every once in a while. It just says the following: Source: ...
1
vote
2answers
442 views

Is NFS very secure? Secure alternatives [closed]

I know that there is a very similar question to that Is NFS Secure Over Internet, but I am asking a little bit different. I guess that NFS is not so secure, as I can learn from the internet and from ...
4
votes
3answers
724 views

Running Viber as another user while using “mine” X Server's microphine and speakers

I run Fedora with GNOME and recently installed Viber for linux. It's very good and all is working just fine. As Viber is not open-source software, I decided to run it as another user to make sure ...
1
vote
0answers
195 views

How to secure Apache/MySql/PHPMyAdmin against brute force/dictionary attacks? (Fail2ban?)

I'm wanting to run a publicly accessible server for web hosting. I'm interested in preventing brute force attacks made against PHPMyAdmin or any other form of authentication process I may include in ...
3
votes
2answers
86 views

Is there any mitigation against touch date/time forgery?

I have been using touch -t to change time of a file when I started using Linux, is there any mitigation against touch date/time forgery? Like, echoing original created date and time, even after using ...
32
votes
4answers
1k views

Why can't I execute shutdown when the permission is rwxr-xr-x?

I'm in /sbin and I see that shutdown has permissions rwxr-xr-x. Doesn't this mean that anyone can execute it?
1
vote
5answers
168 views

Can I stop SElinux from working?

I suspect that SElinux is backdoor and I want to stop it from working on my system. I want to stop it and delete it from the system also if that is possible. Questions How can I delete it without ...
-1
votes
2answers
94 views

Is there any other way to restrict USB storage?

I have been using /etc/modprobe.d/blacklist.conf to restrict USB storage but all employees are given root permissions, so they are removing restriction very easily. What I'm looking for is is there ...
3
votes
2answers
120 views

SSH when to use public key and password?

I think I understand the difference between Public Key authentication and Password. But how do I decide which one to use and which one is most secure in what situation? Can anybody give me some real ...
2
votes
0answers
338 views

Intel Advanced-N 6235 wireless monitor mode problem

As far as I know, iwlwifi drivers (and this particular wireless card) support monitor mode. The only requirement is to install the latest driver from ...
2
votes
1answer
96 views

Could a hacker replace a Bitcoin wallet application with a malicious one in some Linux repository? [closed]

Bitcoin QT is arguably the most popular Bitcoin wallet application. If a hacker gets access to the data and the private key on some machine, he can steal all the Bitcoins from that wallet. Being a ...
-4
votes
1answer
54 views

when update kernels do they close bugs?

I'm not an expert in linux but when I upgrade my kernel to latest stable one which is 3.12.2, does it close all security bugs? How linux security bugs be closed? by installing newer kernel or how ...
1
vote
1answer
725 views

AES-GCM 256bit for SSL on nginx

Does an option exist for AES-GCM 256bit encryption for SSL connections with nginx? If so, how can I configure this as the only cipher used with my server? (I'm hardening my router, so requiring the ...
4
votes
3answers
193 views

restrict student account permissions, give faculty access

I have set up two user groups, students and faculty on Ubuntu 12.04 and created a number of students and faculty accounts. The problem is a student can currently see & read all of the files of a ...
0
votes
1answer
185 views

iptables - why the stun, turn ports are not working to allow end points to access the server?

I have this iptables where all working except tcp/udp port 3478 and 5349. $ cat /etc/sysconfig/iptables # Generated by iptables-save v1.4.7 on Thu Nov 21 10:21:41 2013 *filter :FORWARD ACCEPT [0:0] ...
-1
votes
1answer
81 views

Do I need to wipe and reinstall after possible hacker attack [duplicate]

Yesterday I noticed that the xterm title I use changed suddenly to something strange. So I suspect that someone hacked my Linux laptop (I'm using Arch). I changed the WiFi parameters (pass, essid) and ...
0
votes
0answers
42 views

Prevent scp from asking passphrase [duplicate]

I have enabled private key based access to my server. I have generated the certificates with a passphrase. So to ssh to that machine I have to do - $ ssh -i .ssh/id_rsa_server foo@example.com and ...
3
votes
1answer
460 views

Does this threat still exist: Linux keylogger without root privileges

http://superuser.com/questions/301646/linux-keylogger-without-root-or-sudo-is-it-real Or it's long gone as most of the new distros implement SELinux by default
0
votes
0answers
527 views

Fail2ban - alternative robust for enterprise protection against DoS attack in SIP and similar to fail2ban features

Is there any fail2ban like software for CentOS 2.6.32-358.6.2.el6.x86_64 ? (fail2ban is 0.8.10 installed) but its slowing down the system completely, i was looking for something which can be similar ...
4
votes
2answers
153 views

Is there something like one-time sudo?

Is there a way to have a one-time sudo account? My use-case is the following. I have an Ubuntu station with no remote ssh allowed to that machine. The machine generally serves as a public-use ...
2
votes
0answers
71 views

CUPS and printer security

I would like some help on securing a networked printer. Specifically, I'm interested in the following: 1) Preventing unauthorized access to the printer: I would like only certain laptops that connect ...
2
votes
0answers
139 views

Writing to Arbitrary Memory Addresses [closed]

I'm reading "Art of Exploitation 2nd Ed." and I have a question regarding a section on format string attacks. Target program Below code (fmt_vuln.c) is a target program. #include <stdio.h> ...
3
votes
1answer
185 views

present users a login prompt? /bin/login? getty?

I have a service that execs a command when a user connects to it through a socket, and redirects everything it receives to the executed program. It works ok with shells like bash, giving the user a ...
4
votes
2answers
2k views

rkhunter warn me about root.rules

I run : :~$ sudo rkhunter --checkall --report-warnings-only One of the warnings I've got : Warning: Suspicious file types found in /dev: /dev/.udev/rules.d/root.rules: ASCII text and ...
1
vote
1answer
221 views

How to recognize harmful AUR packages

How do I recognize if a package which is installed via yaourt on arch linux could be harmful to my pc? I read in the wiki that I should check every installation I make with yourt. But what exactly do ...
2
votes
1answer
107 views

How 'passwd' gains ROOT user permissions?

How does Linux knows that it has to give euid 0 (uid of root) to only certain process like passwd, setuid, etc. If a process can gain root user's permissions, will it not lead to security breach in ...
0
votes
2answers
185 views

SSH authentication by public key and password in the same time

Something is not clear to me with SSH authentication. I have a Talend job which connects to sFTP (using SSH protocol) and on the property page of the component, I have the choice between: 1. ...
0
votes
1answer
39 views

Login retrieval in osx [duplicate]

I got an old Mac G4 (powerPC) from the company who wanted to put it in a bin. The company agreed that I can take it home for private use. It is running an early version of OSX but because it is old ...
4
votes
1answer
256 views

Can I set a bash timeout only for virtual consoles (ctrl+alt+{f1-f6})

I know that I can set a TMOUT variable to automatically end a bash session after a specified period of inactivity. However, what I want is to apply that only to my 6 built-in virtual consoles, which ...
2
votes
2answers
267 views

Do I need a special firewall on a personal computer

I am relatively new to Linux and was wondering about security issues. Most people agree that a virus-scanner is not useful on a linux system, but what about a firewall? I am using Debian wheezy stable ...
2
votes
1answer
194 views

GlassFish/Tomcat security issue between domain users in linux server (alternate docroot issue)

Let's suppose we give to different users(clients) different domains (one domain for one user) in our glassfish application server for their work. This glassfish works in centos 6 server. Every user ...
0
votes
3answers
367 views

How to make accessible folder/file to other user

How is it possible to make a folder under $HOME accessible to other users? I thought that's the case why we have softlinks but apparently I am missing some bits here. Can someone please shed a light ...
4
votes
1answer
76 views

Is strace a suitable tool for finding out where a program wrote to the filesystem?

I'd like to determine where a certain app (as an example, surf) writes to the filesystem in order to make sure it leaves no traces. Without a dedicated sandboxing system this probably isn't easy, but ...
1
vote
2answers
182 views

Why can I access all my files without a password when booting with a Chakra Linux live CD?

The other day I burned a Chakra Linux iso on a dvd. When I booted into a live session I was able to access all my regular data. In dolphin when clicking on the icon belonging to my /home/user ...
5
votes
4answers
381 views

Allowing rename but not moving to other directory

Users can upload/delete/rename files via vsftp server and everything works well except they can also move files across directories. Is it possible to allow renaming of files but disallow moving them ...
4
votes
2answers
2k views

How to identify a process which has no pid?

I have a process which listen to 2 ports : 45136/tcp and 37208/udp (actually I assume it is the same process). But netstat doesn't return any pid : netstat -antlp | grep 45136 tcp 0 0 ...
1
vote
2answers
867 views

DNSCrypt, Unbound and DNSSEC

I would like to have an encrypted DNS queries + a DNS Cache + Domain Name System Security Extensions (DNSSEC) . I used this bash script to install DNSCrypt and I choosed to use dnscrypt.eu servers : ...
1
vote
1answer
141 views

Configuring ProFTPd securely in a shared environment

We currently have a LAMP stack for shared webhosting, and are using ProFTP with that. Currently the ProFTP config is fairly stock - users are chrooted to ~. Currently running as the default ...
1
vote
2answers
433 views

Can any user account in Linux invoke command chmod?

Since permissions are sensitive, is it vital to be clear whether a specific user is or not allowed to run command chmod?
2
votes
3answers
320 views

What happens if I delete all user passwords?

I have a Fedora VPS with a root user that has no password. I login with SSH keys. I had another, less privileged account on that server, used for web administration. I've now deleted its password ...
2
votes
3answers
423 views

Use EncFS to encrypt files so that a particular user or process can access them, but root cannot

I have a process which I would like to have access to an encrypted file system. This is very easy to do with EncFS, but this requires a user mounting the encrypted file system, therefore giving any ...
3
votes
1answer
95 views

New webserver: What all user accounts should I create and permissions to provide for

This is a followup on my question here. I am setting up the first webserver and am fumbling with what user accounts to create and permissions to provide for better security. Below is what I have. ...
1
vote
2answers
153 views

What kind of Linux can verify all of its files / packages like debsums(Debian), but more?

# debsums -a, --all check configuration files (normally excluded) However, there is large amount of temporary, ancillary files here and there, not only in tmp-dir. About 4,000 of binaries .pyc ...
3
votes
2answers
159 views

How to harden linux against DMA attacks?

How can I configure my linux system to be secure against DMA-attacks? Is there a way to make them impossible? DMA Attacks excerpt From wikipedia In modern operating systems, non-system (i.e. ...
4
votes
2answers
348 views

How to get a usable full disk encryption with different encryptions for different users

I want to have a full system encryption on my laptop. But I have two users, one for home and one for work and want a separate encryption for both. Sure I could do a full disk encryption with dm-crypt ...
7
votes
2answers
642 views

LXC containers as a sandbox environment

I am currently starting a project evaluating untrusted programs (student assignments) in a secure sandbox environment. Main idea is to create a web app for GlassFish and Java wrapper around lxc-utils ...