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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10
votes
2answers
687 views

How do I prevent programs from sniffing keystrokes to su/gksu?

I've read here that it's possible for any app using the X server to sniff keystrokes to any other app which is also using the X server, including su (on a terminal) or gksu. I've heard of a few ways ...
1
vote
1answer
465 views

How to know who accessed a file or if a file has 'access' monitor in linux

I'm a noob and have some questions about viewing who accessed a file. I found there are ways to see if a file was accessed (not modified/changed) through audit subsystem and inotify. However, from ...
1
vote
4answers
164 views

Erasing HDD , re-write only headers , is that safe?

I want to erase my HDD quickly with dd, so If I only "zeroify" the partition headers , like destroy the inode table, block size etc. But is that safe? UPDATE I have some partition not encrypted ...
2
votes
2answers
658 views

Is xinetd still the best method to let non root daemons listen on privileged ports?

When I need to use SNMP monitoring for java applications, there is the need to that application (usually ran as daemon user) to listen on snmp port. If there is no other alternative, of course I can ...
4
votes
2answers
1k views

Arch: Is “SigLevel = Never” the only convenient way?

The only way I can install majority of packages without rejection from signature database is to put SigLevel = Never in pacman.conf. Its not supposed to be the right way, but I don't seem to be able ...
1
vote
1answer
120 views

A tool that helps me to be sensible on permissions?

Is there a tool or understandable source (manual, webpage, ...) in existence that helps a moderate* user to be more sensible about user permissions? In my ideal-dream-world I'd have a CLI tool that ...
2
votes
1answer
277 views

dm-crypt and LUKS password rotation

How do you protect the master key, and distribute multiple passwords for admin access? Is there a 3rd party user management tool or is this native?
1
vote
1answer
443 views

How do I hide login information passed to command line programs from appearing in the process list?

I have to execute a program that passes in as command line options the username and password. Is there a way to hide the username & password from appearing in the /proc entry for this process.
9
votes
3answers
2k views

Is it safe to close shell just by clicking “X” or using “ctrl+d”?

Is it safe to close shell just by clicking "X" or using "ctrl+d" while logged in as root with su or is it safer to close it by typing "exit"? Is there any difference (security-wise) at all or is it ...
3
votes
1answer
196 views

How are loaded SSH keys referenced by name?

I'm using chef's knife ec2 tool which requires the name of a loaded SSH key (that was created in the Amazon EC2 control panel) It seems strange to me that it uses a name to reference the keypair - ...
1
vote
1answer
258 views

Hamachi for Web Surfing

I recently installed Hamachi on my FreeBSD 9 and I want to know how can I browse web anonymously by this software?
3
votes
2answers
98 views

In Gnome, how do I decide whether to accept a PackageKit software source?

When I try to install software in the Gnome environment of Linux (mine is openSUSE) from a repository that I have not used before, PackageKit asks me to respond "Yes" or "Cancel" to a dialog "Software ...
-2
votes
4answers
256 views

Steps to secure your server? [duplicate]

Possible Duplicate: What to use to harden Linux box? Apparmor, SELinux, grsecurity, SMACK, chroot? I'm just completed install my web server. So what should i do to secure it? I just ...
6
votes
1answer
1k views

Jailbreaking HDTV

I have a Vizio internet TV, the predecessor to this one with basically the same specs, not 3D though. I wanted to try and gain root access to the tv. Using nmap I leaned that the only port open is ...
3
votes
2answers
245 views

SSH Bash Jail Session

I've seen some game tunneling service providers that jails the customer's account to a Information screen upon login and any input is ignored. Ctrl+C closes the SSH session, and disconnecting. This ...
1
vote
2answers
1k views

Allow non-root process to access all home directories without compromising security?

Any ideas how to allow one non-root process to access (read&write) all home directories without compromising security? Normal users should not have access to each other's home directories. All ...
11
votes
3answers
14k views

How can I block a range of IP addresses with an Amazon EC2 instance?

I know a certain range of IP addresses are causing problem with my server, 172.64.*.* what is the best way to block access to my Amazon EC2 instance? Is there a way to do this using security groups or ...
3
votes
1answer
141 views

What is the best way to restraint/secure a workstation?

I want to prevent users to copy on usb devices and some others actions. I was thinking of using polkit. Do you think it is a good solution or does someone know some alternatives ? EDIT: I also need ...
8
votes
1answer
3k views

Linux: LUKS and multiple hard drives

I have a Debian Linux system (amd64) installed on a RAID-1 system encrypted device (LVM on LUKS) and will have a RAID-6 of >=4 disks where I'll put my data (LUKS and maybe LVM). I think the basic ...
2
votes
0answers
119 views

Why do I get a different RSA fingerprint when multihopping using ProxyCommand

I'm using the following config to connect to multihop to the target host (gw2 and target have my public key stored in the authorized_keys file ; no netcat on all systems): Host gw1 HostName ...
2
votes
1answer
313 views

Securely Deleting A File In Ram

I'm running a live distro in ram. I need to write a password to a file. Later, I need to delete it securely. I don't know how live file systems work, so I'm unsure if I open the file for writing, ...
7
votes
5answers
1k views

Securing a Debian installation for general home usage

Debian comes with several harden packages, designed to make a computer more secure. My needs are very simple: word processing and Web browsing. I do not run any special servers, do not use SSH, ...
3
votes
1answer
992 views

Disabling Web camera

My Eee PC comes with a Web cam, which I never use. How can I ensure that it is effectively disabled, so that no software can use it?
1
vote
1answer
859 views

Any better alternative to chroot on an OpenVZ VPS?

Are there any better alternative to chroot environment? I'm thinking about running nginx on a jailed environment. BTW, I'm on OpenVZ VPS, so modifying the Kernel is a no-no. (I think that prevents ...
10
votes
1answer
644 views

Why aren't the Fedora GPG keys signed?

Fedora uses GPG-keys for signing RPM packages and ISO checksum files. They list the keys in use (including fingerprints) on a web page. The web page is delivered via https. For example the checksum ...
6
votes
2answers
698 views

Why did SDF switch from NetBSD to Linux?

I personally don't have much experience, but I was reading about SDF, and at one point the article mentions that SDF migrated to Linux in 1997, but due to the large number of malicious attacks it ...
2
votes
1answer
624 views

SELinux outbound access to other sites with restrictions

We have CentOS 6 configured with SELinux to host a number of websites. Unfortunately SELinux is preventing websites from accessing (outbound) sites, such as download.wordpress.com to update ...
13
votes
3answers
2k views

Can SSH passwords be sniffed out over Wi-Fi?

When you ssh, can the password you enter to connect, be intercepted if you're using untrusted public Wi-Fi (coffee shop, library, airport, etc).
3
votes
1answer
440 views

Does using epub2pdf pose a potential security risk? Is there an alternative?

epub2pdf is a fairly platform-independent program. Based on Java, it executes without a hitch on my machine, with no dependencies. However, strangely enough, the program requires an active internet ...
26
votes
2answers
64k views

What user should apache and PHP be running as? What permissions should /var/www files have?

I just spun up an Ubuntu 11.10 box and then ran apt-get install apache2 php5 to install apache2 and PHP 5 on the box. Now it is functioning as a "web server" and it loads the "It Works!" page. Now I'm ...
4
votes
2answers
3k views

Hardening debian?

So I have thought a bit about hardening a Debian squeeze file & VPN server lately. Right now, we've placed the machine behind a firewall only allowing SSH connections from LAN, set a strong root ...
-3
votes
4answers
486 views

Since Android has malware, does it mean no Unix is immune from malware?

Android has virus: Android.Counterclank, Android.Tonclank (seal info, back-door). Does it prove that FreeBSD, Solaris, Fedora, CentOS, ArchLinux, Ubuntu all is running and having similar ...
12
votes
4answers
2k views

Why do we need a firewall if no programs are running on your ports?

When I try to telnet to a port on a server, and if there is no program listening on that port telnet dies with a "Unable to connect ... " error. I understand that. But, why do we need a firewall if ...
5
votes
3answers
332 views

Preventing binary planting attacks in Linux

If a user account on a Linux machine is compromised, clearly, all files owned by that user are compromised. Unfortunately, if the compromised user also has sudo privileges, it seems that binary ...
12
votes
5answers
6k views

Shell Script mktemp, what's the best method to create temporary named pipe?

I'm aware its best to create temporary files with mktemp, but what about named pipes? I have an idea, I'm sure it would work, but I would really like an expert opinion. I prefer things to be as ...
1
vote
1answer
540 views

portsentry and IPTables on constant reboot, but not sure why

I have been doing some hardening on a new server [ centos 5.7 final ] i also have logwatch and seem to be getting these strange logs Commands Run: User root: /sbin/service portsentry restart ...
10
votes
2answers
2k views

Automatic security updates on Debian squeeze server

For a production Debian squeeze server, what are the best practices or recommendations for handling security updates? I have seen various articles on cron-apt, apticron, unattended-updates, apt cron ...
2
votes
1answer
108 views

Fedora15/Gnome3 - Exit elevated priviliges mode

While using Fedora 14 (Gnome2), Each time if I was doing some privileged task (ex - mounting a new hard drive), I would be prompted for password and then there would appear an icon (like keys) on the ...
5
votes
5answers
2k views

Why is it recommended to create a group and user for some applications?

Most of the time, when installing a program from source it is recommended to create a new user and a new group and give /usr/local/<myapp> the recently created user and group ownership. Why is ...
19
votes
3answers
6k views

Why does the 'bin' user need a login shell?

During an audit of /var/log/auth.log on one of my public webservers, I found this: Jan 10 03:38:11 Bucksnort sshd[3571]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 ...
8
votes
9answers
14k views

How do I write a test for system login?

I've written a Python CGI script that invokes bash commands, and it needs to test for a successful login on the host. How do I write a test for that? For example, could I create a bash script that ...
2
votes
1answer
113 views

What commands should be run when retiring a remotely hosted server?

I have a dedicated server from a friendly host located a substantial distance away from me, so the only access to the machine is SSH. It's a month to month deal, so I don't own the hardware. I'm ...
3
votes
1answer
250 views

sandbox tcpdump under OpenBSD?

From FreeBSD 9.0 tcpdump is sandboxed with Capsicum. Are there any solutions for sandboxing tcpdump under OpenBSD? Just want to secure a running: tcpdump -w output.pcap because it can be only used ...
11
votes
3answers
357 views

Prompt user on Linux security denial

Is it possible to make a Linux security module (eg. AppArmor, SELinux etc.) prompt the user, when an application wants to access classified files or folders (digital signatures, SSH keys, credit card ...
2
votes
1answer
577 views

UFW Limit does not appear to work

I have my ssh port changed to XXX. Then I did ufw limit XXX/tcp However, when I try to login, after 5/6 failed attempts I get thrown back to prompt, but I can try again. Is that supposed to be the ...
6
votes
4answers
3k views

SSH authentication: either SSH keys or one time password

I have an Ubuntu 10.04 Linux server that I normally ssh into (from my home machine) using ssh key authentication. However, sometimes I need to ssh remotely from potentially insecure machines (like ...
2
votes
3answers
3k views

Making sense of auth log

I am seeing some log enties that look like hacking attempts Type 1 Dec 26 03:09:01 ... CRON[9271]: pam_unix(cron:session): session closed for user root Dec 26 03:17:01 ... CRON[9308]: ...
9
votes
4answers
633 views

Good practice to use same SSH keypair on multiple machines?

I recently got a new laptop for work, and I was wondering whether it'd be good practice to keep using the same RSA keypair as I'm using on my old work laptop. I'd really like to not have to create ...
4
votes
3answers
334 views

Linux executable sandboxing?

I'm running a service that allows users to submit code which is compiled and executed on the server. At the moment I'm using Moe and while it works fine for C and C++ code, I've been having some ...
19
votes
6answers
20k views

How do I recursively shred an entire directory tree?

I have a directory tree that I would like to shred with the Linux 'shred' utility. Unfortunately, shred has no -R option for recursive shredding. How can I shred an entire directory tree ...