Content related to computer security.
3
votes
1answer
858 views
I don't want other users see my processes in ps aux. I have root. It's Debian. How to use grsec?
I installed 'linux-patch-grsecurity2' and it has some sort of interface.
~$ sudo gradm2
gradm 2.1.14
grsecurity administration program
Usage: gradm [option] ...
Examples:
gradm -P
...
3
votes
2answers
268 views
Recommended way to login to root?
After I found out hundreds of hacking attempts are made in a day I decided I want to disable logging in to root remotely via a password. But then I found I can't switch users in WinSCP so I can't ...
3
votes
3answers
149 views
Can a user brute-force a directory listing without having read permission on the directory?
I noticed that when a user is working in a directory to which he does not have read permission that using cd produces different error messages, depending on whether or not a subdirectory exists:
$ ls
...
3
votes
3answers
189 views
Creating linux distro for use during exam
I'm thinking about creating a liveCD having some linux on it. The distro (let's call it Exam OS) is meant to be used by students during an exam and should be, at least, unpleasent to bypass. Let's ...
3
votes
1answer
75 views
In my secure log there is a new group added that Im unsure about after adding semanage
I installed semanage onto my CentOS 6.2 box and I was going through my secure log after the install and noticed this entry:
Aug 31 22:12:17 xxxx groupadd[12929]: group added to /etc/group: ...
3
votes
1answer
346 views
How to configure permissions to allow apache to securely have access to a file in a shared environment?
This is a follow up question from my previous, but I felt it might be more Linux based.
http://serverfault.com/questions/414207/how-to-set-linux-permissions-to-allow-apache-to-have-access-to-a-file
...
3
votes
1answer
270 views
How to check downloaded package on OpenBSD 5.1?
Under linux there is a package called "ubuntu-keyring" - it's for checking that the downloaded packages (from the offical repositories) are the ones that are on the server.
How can I do this under ...
3
votes
2answers
77 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 ...
3
votes
1answer
297 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 ...
3
votes
1answer
175 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 ...
3
votes
1answer
94 views
how to disallow user to change process group
Is it possible to restrict a process from changing it's process group? For example, user nobody seems to be able to call setpgid(0, 0) which sets process group of current process to pid of that ...
3
votes
1answer
116 views
How can I run keychain in a way that only has the first shell prompt for keys on startup?
I open multiple shell tabs when I start KDE, and I've just added keychain to my ~/.shellrc the problem is that all the tabs prompt for key passwords when I login. This is quite annoying to do this. Is ...
3
votes
2answers
170 views
Can AIDE scan a directory inside a directory the user doesn't have read permissions for?
I would like to use AIDE to help me verify the integrity of my home directory on a shared Linux system. I am not an administrator of this system. I have built and installed AIDE in my home directory ...
3
votes
1answer
140 views
Why do SELinux policies require a system restart?
When changing SELinux policies, I've been reading that you're required to restart the system. What changes would require this? Are there certain policy changes that would not require a restart?
3
votes
2answers
232 views
How to set secure permissions for multiple users and multiple websites?
On a Gentoo 3.2.12 server with apache2+php, there are several websites running:
/www
/website1
/website2
...etc
The apache user should have read-only access to all the websites. There ...
3
votes
1answer
174 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 ...
3
votes
1answer
1k views
How can I configure SELinux when the semanage command isn't found?
I'm having a very hard time configuring SELinux to allow Sending mail.
Looking into selinux documentation I've found I can manage ports via the semanage command, but the command can't be found.
Is ...
3
votes
2answers
949 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
268 views
Boot-loader to boot to an encrypted partition [duplicate]
Possible Duplicate:
Linux boot loaders supporting full disk encryption?
I am looking for a Boot-loader which is smart enough to boot from an Encrypted partition. I want to place the kernel ...
3
votes
1answer
108 views
Running proprietary software on Linux safely [closed]
As a summer project, I'm looking to prevent any piece of proprietary software like many games I run from having access to my personal files. After looking a lot at sandboxing, I've decided that ...
2
votes
8answers
1k views
How to give a normal user permission to change root password
Please do not ask why, but is it possible to do it?
p/s: I know it's not a good thing, let's just say someone from the top management who is computer illiterate want some sort of control over the ...
2
votes
3answers
372 views
Stracing su and ssh shows the password. Is this a security flaw or am I missing something?
I'm currently fascinated by strace so, being new to it, I decided to play around a little. As suggested by the question title, I tried both strace su and strace ssh. Both commands displayed the ...
2
votes
4answers
5k views
SSH login with clear text password as a parameter?
I need to login to a user that I've created on a remote host running Ubuntu. I can't use an ssh key because the ssh login will happen from a bash script ran within a server that I wont have access to ...
2
votes
3answers
627 views
Is there any chance that some of these processes are malicious?
My significant other and I are sometimes paranoid that a foreign government usually associated with last year's Gmail security breach may be attempting to gain access to our computers.
There were a ...
2
votes
3answers
301 views
rsync server/daemon security
I have a NAS (Netgear Readynas NV+) at home and a linux (Arch) box at work that is always on. The linux box is already running an ssh server/daemon and the NAS is already running an rsync ...
2
votes
2answers
233 views
Disable stack protection on Ubuntu for buffer overflow without C compiler flags
I'd like to try some shell codes and I want to disable linux protections.
I know I could compile using flags but I know another way exists to disable these protections in general I just can't ...
2
votes
1answer
111 views
is it secure /not dangerous to ssh with keys through public transparent proxy?
I use pub key for ssh. Is it normal practice to connect to own server through public proxy? I think with plain pass it is surely dangerous but how about RSA keys?
2
votes
2answers
485 views
Directory/files owned by a non-existent user
A user has created a directory with files, but the user does not exist in /etc/passwd or /etc/group. The system is a Fedora server with an FTP server and proxy which redirects to a CentOS server with ...
2
votes
2answers
375 views
nmap output: what does “uptime” mean?
If I nmap a host, then it outputs an "Uptime" too. What does it mean, is it trustable? Does it gives correct times?
2
votes
2answers
318 views
Moving a root directory to a separate partition
I'd like to create a new partition and move the contents of the /var directory to it for the security reason of having /var/www and other subdirectories "mounted" with nosuid, noexec, and nodev ...
2
votes
1answer
127 views
Can I lock the root account during an install of Debian GNU/Linux 6 “squeeze”?
By default, Ubuntu locks account root; can I do the same, in Debian GNU/Linux 6 "squeeze", during install?
2
votes
1answer
280 views
Is it *really* possible to directly steal a private key if it uses no passphrase?
I've read in various places, such as in this question that using an ssh key pair without a passphrase allows attackers to steal your private key if they gain access to your account. I assumed that by ...
2
votes
2answers
583 views
Preventing access to TTY when X is killed
Assume I start an X server manually from a virtual console /dev/tty1 with xinit or startx, with the line id:3:initdefault: set in /etc/inittab. The X server gets run and put on another virtual ...
2
votes
2answers
121 views
SSH encryption security
If I log in to my server through ssh and copy files to my local computer can I be eavesdropped?
How do I make sure nobody can intercept the data or even know what I am copying?
Are there levels of ...
2
votes
2answers
123 views
need explainations on this network route
I'd like to get some insight as to how I can possibly access network devices that are on a different IP range (obviously not mine) compared to what is configured on my wifi router?
setup
home wifi ...
2
votes
1answer
440 views
Deny external SSH access to a user
Is it possible to deny access to a user (in my case www-data) from outside the network? Or possibly deny this:
ssh www-data@example.com
But allow this if already logged in:
su www-data
2
votes
1answer
93 views
Port 110 visible to the outside world - necessary or a bad idea?
I just did [a test][1] that told me my gateway's (debian squeeze) port 110 is visible from outside.
It's a box with two network cards, eth0 is for my internal network (192.168.1.0/24) and eth1 goes ...
2
votes
3answers
163 views
How can I securely login remotely to my Linux box over the internet?
I'm pretty much a Linux beginner, but this question has been on my mind. What's the simplest, most secure way to connect to my computer at home from work or from the library, &c? I'm running Mint ...
2
votes
2answers
106 views
How to securely export a device (HDD)?
So I have a Scientific Linux 6.3 (RHEL clone so basically the question is Redhat related) machine called "B" (with an extra "A" HDD besides the system HDD) and a notebook with SL 6.3. They are in a ...
2
votes
3answers
903 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]: ...
2
votes
1answer
989 views
Encrypt files using gpg (and them symetric encrypting the key) - is it a normal thing to do in the *nix world?
I read a lot of articles about using gpg to encrypt email, but I would like to use it to encrypt some files - mainly a bunch of *.isos. I'm going to describe what I thought I would do, so you can ...
2
votes
2answers
134 views
How to deny rdesktop access to others?
Someone keeps trying to connect to my Ubuntu machine through remote desktop. Is there any way I can determine who it is, and permanently block access to my machine?
2
votes
4answers
465 views
sudo without password - security? [duplicate]
Possible Duplicate:
What specific vulnerabilities am I creating by disabling the sudo password?
I'm involved yet again in the old argument on whether sudo without password is secure enough ...
2
votes
3answers
900 views
Private VLAN's under Linux?
http://blog.ine.com/2008/07/14/private-vlans-revisited/
Has anyone tried private vlan's under Linux? Any experiences with them? My real question is does anybody have howtos regarding this?
2
votes
3answers
155 views
Check outgoing network traffic
In Ubuntu, how can I check what information is being sent through the network connection, what programs are doing it, and what sites is my computer connecting to?
I am not paranoid about security, ...
2
votes
2answers
99 views
Do I need to remove all “java|jre” packages from my system to be secure from java vulnerabilities?
Currently I have these installed on my Scientific Linux 6.3:
[root@localhost ~]# rpm -qa | egrep -i 'java|jre'
java-1.7.0-openjdk-1.7.0.9-2.3.7.1.el6_3.x86_64
...
2
votes
1answer
80 views
Is running programs as another user useful?
After watching a talk by Douglas Crockford on security where he talks about how browsers got the right answer to the question "Who's interest does the program represent?", I wondered if it was ...
2
votes
1answer
58 views
Apache boot without asking for passwd
So I'm maintaining a server which has a verified SSL certificate setup, however there is a password on the private key and so whenever apache is reboot, we get a message asking for the password. This ...
2
votes
1answer
770 views
iptables rule to allow access to internet
I made default policy of my machine-
iptables -A INPUT -j REJECT #DROP ALL PACKETS TO INPUT CHANNEL
INPUT channel has been blocked. Now I want to allow only some specific services like I should be ...
2
votes
2answers
304 views
Security with Kernel IP Forwarding Enabled
I recently enabled IP Forwarding on a production web server that also acts as a VPN server. What, if any, security issues did I just set myself up for? And are there any iptables rules I should set ...
