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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9
votes
2answers
6k views

rkhunter warns 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 ...
0
votes
1answer
310 views

rkhunter warnings about a script and a hidden directory

When I run a scan with rkhunter I get 2 warnings. I checked the log file and warnings are as the following: Warning: The command '/usr/bin/unhide.rb' has been replaced by a script: ...
0
votes
1answer
180 views

rkhunter warning about ssh root access when that access is not allowed on the system

I just ran rkhunter --check and all was good except this: Checking if SSH root access is allowed [ Warning] What does this warning mean? SSH root access is not allowed on this ...
0
votes
1answer
226 views

Setting up connection to WPA2 Enterprise (PEAP/MSCHAPv2) with two-level certificate

For a long time, I have been able to use NetworkManager + wpa_supplicant as configured in Debian 7 to connect to a secure wireless at work (which is WPA2 Enterprise, with PEAP + MSCHAPv2 ...
2
votes
3answers
858 views

Check that fail2ban is running?

I just installed and configured fail2ban. I want to make sure it is working. I don't want to block myself from the server so I can't just login (poorly) a bunch of times. How do I see that fail2ban is ...
1
vote
2answers
41 views

eCryptFS and FIPS 140-2

I've searched high and low for information on whether eCryptFS encryption is FIPS 140-2 compliant. I've found information on other filesystem or block encryption and their FIPS compliance I presume ...
0
votes
1answer
3k views

fopen: $JOHN/dynamic.conf: No such file or directory

I have an unshadowed db.txt file: [root@SERVER ~]# rpm -qa | grep -i john john-1.7.9-1.el6.rf.x86_64 [root@SERVER ~]# head -1 /etc/issue Scientific Linux release 6.3 (Carbon) [root@SERVER ~]# cat ...
2
votes
1answer
52 views

Things to check after a untrusted USB device was mounted

Suppose you plugged an untrusted usb-stick into your linux machine (as user) and browsed and copied some files, perhaps using a graphical interface. After the usb-stick is removed (and not available ...
52
votes
3answers
13k views

Why is there a big delay after entering a wrong password?

I notice a weird (well, according to me) thing about passwords. For example, if I type an incorrect password during login, there will be a few seconds' delay before the system tells me so. When I try ...
8
votes
3answers
354 views

Trap: can't su as root, can't change group to wheel, ssh as root prohibited

Is this a trap? I made these steps in FreeBSD 10: 1) ssh as root prohibited 2) logged as user 3) su as root 4) as root chsh changed name of user "user" to "luser" 5) exit from ...
3
votes
1answer
102 views

OS X FileVault 2 duress password

I've been attempting to add a custom script to run after the FileVault password is entered on login that will check whether it a 'special password' that will run a script in the background after ...
55
votes
2answers
2k views

Security implications of forgetting to quote a variable in bash/POSIX shells

If you've been following unix.stackexchange.com for a while, you should hopefully know by now that leaving a variable unquoted in list context (as in echo $var) in Bourne/POSIX shells (zsh being the ...
0
votes
1answer
48 views

How can I configure my server to avoid information leakage from the SERVER header of its HTTP response

I have a centos 7 server with apache v2.4.6 php 5.4.16 and OpenSSL 1.0.1e-fips installed. I was just doing a scan to it to see how secure my server is. I found out that my server is giving out ...
1
vote
6answers
475 views

Hiding Password in Shell Scripts

How can I hide a password in shell scripts? There are a number of scripts that are accessing database. If we open the script others also aware the username and password. So if anyone knows how to hide ...
0
votes
1answer
30 views

Strange commands on FTP logs

I'm battling with wordpress security problems and sometimes even I have tried everything my server sends spam by some hacker. I have checked my FTP log and I found this code ...
1
vote
1answer
42 views

How the kernel can prevent a malicious program to operate?

If I write an x86 assembly program that tries to fetch and analyse all the addressable memory space. How the kernel can prevent this operation to be done? I am more familiar with small CPU ...
23
votes
4answers
69k 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 won't have access to ...
2
votes
2answers
1k views

AIX 6.1 — Without root can I get the last failed login for a user i have access to?

I know the information is in the security files but I don't have access and it's more work then I want to do to go to our Unix admins to get the information (everytime the account gets locked which is ...
0
votes
0answers
18 views

How to access boot: invite?

I'd like to simply try a root pawd reset, by entering linux single whan systems display boot: when booting. But my Mint system goes directly to user home prompt. Tks
4
votes
5answers
21k views

vsftpd fails pam authentication

Moving a tried-and-true vsftpd configuration onto a new server with Fedora 16, I ran into a problem. All seems to go as it should, but user authentication fails. I cannot find any entry in any log ...
1
vote
2answers
41 views

Prevent certain lines of a script to run as root

Suppose I am writing a shell script that requires root privileges to run, for example- #!/bin/sh ip -s -s neigh flush all ufw enable How can I prevent certain lines of code to be run as root, i.e. ...
1
vote
1answer
33 views

How to trap an event when a file with a specific content (given by e.g. checksum) was created on the local file system?

I want to implement sort of trip-wire security mechanism, that tracks in real time events when user writes a file with a specific content on hard drive of his workstation (which will be managed by ...
14
votes
3answers
8k views

How should one set up full-disk encryption on OpenBSD?

Is there a preferred method to set up full-disk encryption under OpenBSD, similar to dm-crypt under Linux? I'm looking for full-disk encryption, as if someone were to steal my notebook they could ...
0
votes
0answers
27 views

Encrypt some folder and hide key in Linux

I work on a Debian system (Mint actually). I'd like to encrypt some folders and files, for instance: the one with OpenVPN configuration and keys, and be able to decrypt it on the fly. My problem: ...
2
votes
1answer
88 views

How to safely transmit a password over SSH for a remote command to use

On the local server, I have a program that stores the password in the predefined environment variable (SPECIAL_PASSWORD). On the remote server I have a program that reads and uses a password from a ...
5
votes
1answer
514 views

SELinux is preventing /opt/google/chrome/nacl_helper from getattr access on the file /etc/passwd

Is this a bug or a real security concern? It appears to have been discussed but I still don't understand why this is happening and what is being done to address the root cause (I am not going to ...
1
vote
3answers
407 views

how to record all who that login to my linux machines and records them

I installed the package audit on my linux red-hat 6.x machine in order to view the recored of each user that log to my linux machine yum install audit kit installation from: ...
2
votes
2answers
36 views

How can I set up a secure LAMP stack on CentOS?

I have been using linux for years, but I need some clarification on what are probably pretty basic principles to how the OS works, but I definitely need clarification due to security concerns. I am ...
12
votes
3answers
31k views

How to ensure SSH port is only open to a specific IP address?

This is my /etc/sysconfig/iptables: It has two ports open 80 apache and 22 for ssh. # Firewall configuration written by system-config-firewall # Manual customization of this file is not recommended. ...
43
votes
4answers
8k views

Why is root login via SSH so bad that everyone advises to disable it?

Everybody on the Internet advises to disable root login via SSH as it is a bad practice and a security hole in the system, but nobody explains why it is so. What is so dangerous in enabling root ...
2
votes
1answer
116 views

How to Mark Traffic using IPtables?

I'm trying to mark traffic, How shall I write following code in terms of IPtables? /ip firewall mangle> add chain=prerouting src-address=10.1.1.1/32 action=mark-connection \ ...
2
votes
1answer
42 views

What is the difference between the FreeBSD flags, immutable and unlink?

What are the differences or similarities among the FreeBSD flags, simmutable/uimmutable and sunlink/uunlink? Reading man chflags, I see these flags: schg, schange, simmutable set the system ...
1
vote
4answers
15k views

Helo command rejected: need fully-qualified hostname Error

My mail server is in some blacklist cause of spams. I reconfugured postfix. Aften then My customers get this error they can't send emails. 404 4.5.2 <PLLAMNAZIFE>: Helo command rejected: need ...
1
vote
0answers
64 views

nmap doesn't detect opened port [closed]

I'm testing some vulnerabilities on a machine which has the port 22333 opened (it's used as the ssh port, and I can connect to it without any problem and I can get connected as well with the telnet ...
1
vote
2answers
88 views

iptables configuration - ssh connection only from a remote network

I'm trying to configure Iptables of a server in order to permit SSH incoming connections only from a certain network. by the way this is the rule chain : # Drop anything we aren't explicitly ...
2
votes
1answer
116 views

Using mailx without storing a password

I'm trying to setup mailx to use my Gmail account. I've found a configuration that can send mail successfully but it requires me to store my email password in a configuration file in my home ...
2
votes
3answers
62 views

Does a Certificate Authority represent my company or a server?

I am setting up my second OpenVPN server with TLS and so I have a question about CA. Should I create a separate CA for each server or use the same? Why? Both servers will cater to the same network ...
5
votes
1answer
79 views

How to enable random PIDs on Linux?

I'm currently comparing random PID implementation on OpenBSD, FreeBSD and Linux from security perspective. As long as OpenBSD and FreeBSD are concerned, my work is done. However, while the answer ...
1
vote
2answers
38 views

OpenVPN : protect your clients key/cert/conf from being stolen?

I have configured an OpenVPN install. Mode: multiclients 1server. Clients are raspberries. I note how easy it is to steal a rasp, and look in HDD to get key+cert+conf. Copy it on your laptop, and ...
8
votes
3answers
1k views

Is it a good practice to run a daemon under a non-root user account?

I've developed an application that uses NTP to change the network time, to sync two of my computers. It runs as root, since only the latter is allowed to change the time and date on Linux(I guess). ...
0
votes
0answers
21 views

Where to put the ASCII WPA2 Wifi Key in MacOS X?

I tried to make some research about wifi security in our company: So i tried to het WPA2 Wifi key using wifite tool in Kali linux distribution. After the few attempts i get WPS PIN and WPA2 KEY: ...
0
votes
1answer
48 views

What are the best practices for permissions and and methods for generally avoiding using sudo? [closed]

The main point is that I only want one user to have sudo access - really only for use in set up and emergencies. I don't even trust myself with sudo access all the time. Are there best practices ...
12
votes
6answers
59k views

How can I monitor all outgoing requests/connections from my machine?

My machine is a server so I want to ignore connections being made to my server (e.g. when someone visits my website). I want to see only connections/requests being made by my server to other places. ...
1
vote
0answers
52 views

What is the best operating system for beeing anonymous [closed]

Im looking for an anonymous distribution of linux, anyone can help me? Thanks
0
votes
4answers
121 views

How to track/log commands executed on a shell?

Can commands be written to a logfile before they were executed in any shells? I know there is a patch for ssh to log all commands from ssh sessions, but i want to log even commands executed from a ...
1
vote
0answers
28 views

Is there any considerations I should take when running untrusted apps as non-root user?

I have to use an application I don't trust (unstable) and I will run it as a non-privileged user so if something bad happens the damage would be limited to the home folder of that user. I removed ...
93
votes
8answers
14k views

Which is the safest way to get root privileges: sudo, su or login?

I would like to have the root account in safety even if my unprivileged user is compromised. On Ubuntu you can only use sudo for "security reasons" by default. However I am not sure it is any safer ...
0
votes
2answers
93 views

Execute scripts without decrypting them

I have a set of scripts (bash, ruby, python) and want to put everything into a container like file so I can deploy this container on a lot of servers. This scripts need to protect from accessing other ...
0
votes
2answers
94 views

SSH authenticity couldn't be established

Last night I SSH'ed to different systems.... one system/SSH reported that the "authenticity of HOSTNAME couldn't be established......." and it asks if I want to continue or something, I didn't and ...
0
votes
0answers
44 views

Use sudo as login

I've picked up the habit of using sudo and disallowing root logins. In cases, sudo is integrated with GUI configuration tools that require it. Are there any serious efforts to replace login and ...