Content related to computer security.
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0answers
12 views
ufw in laptop running Ubuntu
I installed ufw and enabled it. The status is:
Status: active
Logging: on (low)
Default: deny (incoming), deny (outgoing)
New profiles: skip
But, I am able to navigate the web, get emails and ...
2
votes
1answer
60 views
How to lock-down input on a Linux machine?
We need to put out a web browser to a public place to show informations. I need to lock down all the input interfaces via software methods. So ex.: if someone plugs a USB keyboard to the machine it ...
0
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0answers
26 views
Installing Ossec on an existing centos 6.4 machine
I have an existing machine running centos 6.4. Is it ok to install now the Ossec or it's not worth any more as the machine is already running for few months.
Which is the best mechanism to install ...
2
votes
1answer
30 views
Benchmarking Apache using ab
I was doing some performance testing for Apache using ab. Apache in our case is only working as a load balancer balancing load between two Liferay servers.
Initially, I did the testing for 1000 ...
5
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1answer
59 views
Does fail2ban offer any additional protection to SSH if password login is already turned off?
I’m setting up a Debian VPS on Linode to use as a public web server, and I’m following their security suggestions.
The last suggestion they make is to install fail2ban, to avoid dictionary attacks on ...
0
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1answer
41 views
How to generate 4 WEP keys with linux commands?
I have a sagem router. this router is able to generate 4 WEP keys from a given passphrase.
Example:
Passphrase: "hahahahahahahahahahahahahahahahahahahahahahahahahahahahahahahaha"
key1: ...
4
votes
1answer
131 views
Which home directory should 'nobody' have?
I'm messing around with Tiger security audits on my CentOS box, ensuring the server is fit for being online, well as close as it can get anyway.
I noticed a warning about the user nobody having / as ...
2
votes
2answers
64 views
files in /proc/$PID (e.g. ssh-agent, Chrome) are not owned by user but by root
I am just answering another question here :-) and thus had a look – wanted to have a look at /proc/$PID/fd of ssh-agent in order to find out which socket it uses. But I can't. I am quite surprised to ...
1
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1answer
57 views
LAMP Server setup for personal development
I am setting up a LAMP server in VirtualBox for personal development. This will be an Ubuntu Server 12.04 install, and I will be using Virtual Hosts for Drupal, Yii, and other small PHP apps. Ideally ...
-1
votes
3answers
84 views
Is there a way to 'authorize' a command typed in by a user?
is there a way we can authorize a command typed by a user before it takes effect?
For example, when a user types cp file1 file2, the command will not be executed and a root / root-equivalent user ...
1
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2answers
56 views
How to make sure the shell builtin echo is invoked so that its not visible in process list?
Is this going to be visible in the process listing if the below line is executed from a command line or a shell script
bash -c "echo $password"
or
i just need to do echo $password from within ...
-1
votes
4answers
51 views
How to list all daemon users?
A typical Linux system has not only accounts for the actual user(s) of the system, but also various system accounts.
Is there any file like /etc/passwd for daemons?
I heard that it is possible to ...
2
votes
1answer
31 views
Nemo: Forget encryption password
I have mounted an encrypted disk by selecting it in Nemo (1.1.2), then typing a password. I can unmount the disk using Nemo, but now it can be remounted without requiring the password.
Probably ...
1
vote
1answer
33 views
How to retrieve information about locked accounts
Is it possible to retrieve info regarding to locked unix accouts?
I am interested in seeing information about what date and time the lockout happend and from what hostname (pc name). I would like to ...
1
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0answers
44 views
How to add my own created certificate authority to system trusted repositories
I was told that I can add my created CA to trusted repositories/authorities in my system instead of adding it from browser and configuring in in ssl.conf.
Yet I can't find anything similar on the ...
1
vote
1answer
86 views
How to “close” open ports?
A few days ago I started to care a lot about my data security, I end up nmaping myself with: nmap 127.0.0.1
Surprise, surprise, I have lots of active services listen to localhost:
$ nmap 127.0.0.1
...
2
votes
1answer
66 views
Is it possible to specify groups in /etc/security/capability.conf?
I've been inspired to start playing around with Linux capabilities again, my pet project is to replace the setuid on a lot of the binaries and provide access to additional privileged utilities to ...
2
votes
1answer
42 views
wpa_supplicant store password as hash (WPA-EAP with phase2=“auth=PAP”)
Is there a way to store my password in /etc/wpa_supplicant/wpa_supplicant.conf as some hash instead of plaintext?
By "password" I refer here to the password used for phase2 authentification. I do not ...
0
votes
2answers
39 views
unable login solaris box
There is problem on my Solaris 10 box.
It's not possible to access directly to the box, but via ssh from another box after 3 wrong entries of username/password to box then login prompt changes , at ...
2
votes
2answers
87 views
How to encrypt my system such that suspend to RAM works and is also encrypted
How can I encrypt my system (at best using lvm + dm-crypt/luks) such that suspend to RAM works and that everything is in an encrypted state when suspended to RAM?
2
votes
1answer
21 views
How can I use ForwardAgent with keychain, or detect a new login?
My scenario:
I have Server A at home, and Server B at my parents house. I also have Laptop A and Laptop B at home. I do all sorts of strange ssh hops - I might connect Laptop A -> Server A -> ...
2
votes
1answer
33 views
Sign a module after kernel compilation
I've built a kernel in tmpfs, then I rebooted.
Now I see a message when I compile the 3rd party module,
NO SIGN [M] XXXX.ko
How can I get it signed? The key pair generated during rpmbuild is lost ...
7
votes
4answers
178 views
Which data should be excluded from log files , error messages etc. if posted online?
What data should one erase from log files, error messages etc., if posting them as a screenshot so as not to expose sensitive information? As I have little knowledge about this topic, I can vividly ...
1
vote
1answer
39 views
Having the 'id_rsa.pub' file in my dotfiles public repo securely
So this is something that I'm wondering, how can I have this file in my dotfiles GitHub repo?
I'm sick and tired of having to generate a new SSH key every time I'm on a new computer or re-install my ...
1
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2answers
67 views
How to find out out WHEN an user account was locked
With passwd -S user_name one can find out, if an account is locked, but is there a way to find out when it was locked and who it locked?
Further links:
http://serverfault.com/a/485760/78439
Disable ...
10
votes
1answer
149 views
Can entropy consumption at program start be prevented?
I use Knoppix (or other Live CDs/DVDs) as a secure environment for creating valuable crypto keys. Unfortunately entropy is a limited resource in such environments. I just noticed that each program ...
3
votes
2answers
67 views
Fully seperate two accounts without installing seperate operating systems?
Our class is finally installing Mint Linux on our machines. The problem is our teacher is scared that we'll play war games against the two classes that use the computers. His solution is to install ...
0
votes
2answers
208 views
How do I make PHP securely load files from the server root home folder on CentOS?
So I built what I thought would be this awesome reporting page in PHP that loads data from some CSV text files and creates nice Google charts and tables for our clients. I then thought it would be ...
2
votes
3answers
142 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, ...
4
votes
3answers
138 views
Can someone execute a malware by just inserting a flash disk?
I know that Linux is virus proof, but just to be sure...Suppose someone writes a script, trojan, etc... and put it on a flash disk or CD. then I insert that flash in my system without clicking on any ...
6
votes
2answers
105 views
ssh-agent: don't forward authentication for the whole keyring
I have two private ssh keys :
one to access my personnal machines,
one to access servers at my job.
I add those two keys to my ssh-agent with ssh-add.
Now, when I do ssh -A root@jobsrv I ...
2
votes
1answer
132 views
Best way to encrypt my system on an ssd
I consider to buy an ssd for my laptop (something like Samsung 830 or 840) to make the system more responsive. I want my system (at least my home partition) to be encrypted. However I know about ...
1
vote
3answers
86 views
Taking away a User's Read/Write/Execute Permission
So I have a user that is able to go in /etc and read files like httpd.conf.
I would like to deny that user access to any critical locations such as /etc, /var and so on.
What would be the best way ...
1
vote
5answers
269 views
How to securely automate running commands as root with “sudo su -”?
hint (on client side, how to encrypt files/pwd's):
# encrypt pwd with ssh key:
openssl rsa -in ~/.ssh/id_rsa -outform pem > ~/.ssh/TEMP-id_rsa.pem 2>/dev/null
openssl rsa -in ~/.ssh/id_rsa ...
4
votes
1answer
114 views
What does the Chromium option `--no-sandbox` mean?
I'm running Chromium like so : chromium --no-sandbox
I'm doing this because I'm running Debian Squeeze on an OpenVZ VM Container and it's the only way I can get it to work.
Though I keep reading ...
4
votes
3answers
203 views
Restrict ssh login from LDAP to users who have a /home directory
I have an Apache server (RHEL 6) hosting multiple user web pages which currently is connected to my Active Directory environment to authenticate users. The server is used to automatically host content ...
3
votes
1answer
72 views
How does having /dev/fd make running shell scripts under sudo safe?
At the end of the man page for sudo, there's the following remark:
Running shell scripts via sudo can expose the same kernel bugs that
make setuid shell scripts unsafe on some operating systems ...
0
votes
1answer
28 views
How to identify which application is trying to access the unixbuild server?
The error message I am seeing is:
Failed publickey for raj from 10.*.*.** port 34355 ssh2
Mar 18 05:22:34
unixbuild sshd[16956]: [ID 1000034 auth.info] Failed password for raj from 10.*.*.* port ...
2
votes
1answer
54 views
Configure SSH keys for production and DR server
Here is the case, we have successfully configured SSH keys (and hence password-less SFTP connection) between ProdServer-A to ProdServer-B. It works, or so I thought still yesterday. Yesterday ...
5
votes
1answer
174 views
Ubuntu: If anyone can get a root prompt without password, isn't that compromising the gnome keyring?
I've been looking for this for quite a while now but couldn't find a satisfying answer.
My scenario:
I'm using encfs to encrypt a few directories in my home folder. To make it easier to access I set ...
24
votes
1answer
397 views
What would be the best way to work around this glibc problem?
I administer a Gentoo Hardened box that uses file capabilities to eliminate most of the need for setuid-root binaries (e.g. /bin/ping has CAP_NET_RAW, etc).
Infact, the only binary I have left is ...
1
vote
1answer
116 views
Securely reading and parsing a string from a parameter or file in bash
I've been writing a number of bash scripts lately which get variables from a parameter or from a file. Some of the scripts run as root (using sudo)
This is on my notebook, so there aren't any other ...
1
vote
5answers
136 views
How do I disable copy permissions?
Can we set permissions, on a Linux box OR for a particular directory (Scientific Linux in my case) that, one can read files but cannot copy, move or delete them?
Update: My Scenario is,
We developed ...
2
votes
2answers
230 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 ...
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votes
1answer
69 views
Priviledge separation for Firefox (aka: how to secure webbrowsing)
I do this on Scientific Linux 6.3 (to implement it, it requires a minimal Linux knowledge):
Shared directory for downloads
Remember you can only copy from or to this directory, never "move" files ...
2
votes
2answers
98 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
79 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 ...
4
votes
1answer
89 views
Why Nmap fragmented scan on Linux is only working from virtual environment?
OLD QUESTION AND TITLE (Look further down for the updated question):
Why Nmap fragmented scan is only working on Backtrack?
I spent quite a few hours today trying to capture and study some ...
4
votes
3answers
101 views
Is a command's stdout to the terminal being logged?
I am interested in learning whether a command's output to the terminal is logged somewhere.
Since that can be a bit too generic, what about cat (and ccat) in specific? If I use cat on a file, will ...
2
votes
1answer
90 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 ...
