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.

learn more… | top users | synonyms

2
votes
1answer
56 views

Possible attack against VNC Server

Recently I started to have some problems with my Linux machine. So I have this Linux VPS machine with VNC server installed and I just connect to it by using VNC viewer. Recently the VNC server/...
7
votes
0answers
140 views

Taking a picture with a laptop webcam after entering an incorrect password

I'd like to set up my laptop so that if a wrong password is entered when the screen is locked, a picture is taken using the laptop's webcam. I examined xlock (from xlockmore package), but there is no ...
4
votes
1answer
786 views

In my secure log there is a new group added that I'm 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: name=cgred,...
3
votes
0answers
40 views

Can't disable TLSv1 and RC4-SHA

I need to remove TLSv1 and RC4-SHA support in Centos 7. I have these lines in my ssl.conf SSLProtocol +TLSv1.2 +TLSv1.1 -TLSv1 SSLCompression off SSLHonorCipherOrder on SSLCipherSuite "ECDHE-ECDSA-...
1
vote
0answers
44 views

How to reboot a server with a LUKS encrypted partition

I have a CentOS 6 VM on which I used the following shell script for installing and configuring MongoDB to use a secondary LUKS (dm-crypt) encrypted disk for its database files: #!/bin/bash -e # Set ...
0
votes
0answers
19 views

removal of cleartext passwords from clogin.rc file of RANCID

We are trying to avoid the usage of cleartext passwords in .cloginrc file of RANCID by using CyberArk API which provide passwords ondemand . API is capable to made available passwords of accounts been ...
0
votes
0answers
24 views

How does reboot run without root password on the console? Can I get this to happen with other programs? [duplicate]

I login at the graphical console terminal on basically stock RHEL Linux 6, and type reboot in the command window. The system reboots without being asked for a password eventhough I am not the root ...
0
votes
0answers
11 views

parsing audit logs of rootsh

We're using rootsh for auditing users privileged shells. This unfortunately means they want to push the problem of auditing up to infosec, but here in infosec, the logs are not very readable. E.g., ...
108
votes
7answers
71k views

Allow setuid on shell scripts

The setuid permission bit tells Linux to run a program with the effective user id of the owner instead of the executor: > cat setuid-test.c #include <stdio.h> #include <unistd.h> int ...
0
votes
1answer
51 views

How to turn off stack protector in linux kernel easily? [duplicate]

I wrote a simple module for the Linux Kernel and it has a stack buffer overflow vulnerability. I want to exploit the module, but I have to turn off the stack protector in the kernel first. How could I ...
0
votes
1answer
60 views

How can I make Linux as secure as possible? [closed]

I am relatively new to Linux, and I love it. With the rise of Windows 10 I am getting more concerned about my privacy and the risks of using an unsecured system. My question is three fold Which ...
5
votes
4answers
2k 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 ...
0
votes
1answer
42 views

Debian Security Updates

If I am running an 'unsupported' version of Linux, which is based on Debian, is there any way that I can still get the updates from debian systems as they are released? OR am I stuck waiting on the ...
0
votes
1answer
139 views

Mediawiki support has been dropped in Debian stable (jessie). What's the alternative?

Yesterday, Debian removed Mediawiki from its stable distribution: Removed packages ---------------- The following packages were removed due to circumstances beyond our control: +--------------------...
0
votes
0answers
16 views

Git + Nginx - Is it safe to have https auth for cloning and pushing to repo, while remove any auth from gitweb block?

I have following nginx configuration on Ubuntu 14.04 to use together with git httpd backend and gitweb to anonymous browse of repo and push/clone with authentication. Is it safe to use such or I ...
18
votes
7answers
15k views

Can root/superuser read my read-protected files?

On shared unix hosting, if I have a file sensitive-data.txt and I issue: chmod 600 sensitive-data.txt Can root user still read my file? Specifically I'm wondering if it's safe to store my password ...
1
vote
1answer
24 views

How to extract RSA keys from Apache

I am testing some old vulnerabilities related to SSL/TLS, and would like to know how to extract temporary RSA keys from Apache. The particular vulnerability I am testing is the FREAK attack. I ...
0
votes
0answers
9 views

Send new login & logout logs to a database

I want to know how to send new login and logout logs to a database. I know that last command outputs the "lasts" login info. But, I found the following problems? How to filter to only get new logs? ...
3
votes
1answer
49 views

How does chsh prevent users from changing another user's shell?

I know chsh is used to change a user's login shell by modifying /etc/passwd. So, in principle anyone could run this command and change another user's default shell but that is not allowed. How is ...
1
vote
0answers
8 views

Looking for a tool similar to the Security Advisor plugin for WHM that can run on CentOS 7 without WHM

The startup I'm working at is setting up some new CentOS 7 servers that will host a mobile application, and some of the data is sensitive, thus, the servers need to be secured to the best of our ...
1
vote
1answer
29 views

Globally writable files and user-based process jailing

I want to be able to generically pick a certain executable (potentially malicious) x and run it (from an admin account) with write access restricted to certain directories (dynamically deduced) "${...
2
votes
1answer
3k views

I stopped MiniSSDPD, will something bad happen?

I have been trying to harden my Debian system by stopping and disabling the 20 or so unnecessary services listening by default. One of them is called "minissdpd". Apparently this provides "discovery" ...
11
votes
4answers
11k views

What are the world writable directories by default?

In a standard Linux filesystem, which of these common directories are world-writable by default? /tmp /etc /var /proc /bin /boot /.... .... Why are they world-writable? Does that pose ...
1
vote
1answer
52 views

How is the authenticity of Debian packages guaranteed?

What security systems and processes are in place to prevent malicious third parties from hacking/compromising the security of code in the Debian mirrors, or to verify that the packages we get are in ...
1
vote
3answers
49 views

Does it make sudo more secure when indexing all commands by their SHA-2 checksums?

I'm asking myself whether system security substantially increases when I generate a security policy, i.e. sudoers file which contains one or more Cmnd_Alias definitions that enumerate all executable ...
0
votes
1answer
20 views

Add a second authentication to user log in

trap '' 2 code=`oathtool --base32 --totp "xxxxxxxxxxxx"` echo -n Enter Code: read -s password echo "" if [ "$password" == "$code" ]; then echo "You are allowed in" else exit fi trap ...
0
votes
1answer
41 views

Suspicious traffic in nethogs on fresh install

Earlier today google said that unusual traffic was emanating from my computer and gave me a captcha. I got curious and installed nethogs. Everything appears normal except for an unknown program ...
5
votes
2answers
1k 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 ...
0
votes
1answer
29 views

2 factor login for gui and ssh imposes verification for sudo use

tldr: how can I make it so I don't have to use a verification code to sudo? Hello, I followed this guide on how to setup 2 factor login for my debian install. I have it so when you try to login ...
27
votes
6answers
32k 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 ...
8
votes
2answers
197 views

Why is the ability to define functions in an environmental variable not a security risk in itself?

As I understand it, generally it is considered safe to let anyone provide information that will be stored in an environmental variable. The shellshock vulnerability is an issue here because it means ...
4
votes
1answer
3k views

STIG (Security Technical Implementation Guides) automation

Has anyone here found the best way to STIG a version of RHEL 6.x automatically? The other answers I have found are either out of date or do not completely STIG the machine. Even an image that has a ...
1
vote
0answers
39 views

pam su authentication with RSA token [closed]

We are implementing RSA token authentication in our company and management decide su - should ask for RSA token passcode for individual (listed users) user. So no-one is going to get root password: it'...
2
votes
2answers
34 views

ptrace suid binaries after privilege is dropped

I understand that we probably cannot do ptrace on suid binaries. However, I'm wondering why we cannot do ptrace after the binary drops its previlege to uid instead of euid. For example, in the binary ...
13
votes
2answers
2k views

How to safely pass variables to root-enabled scripts?

This question is totally general and not only applicable to my situation, but... I have a small busybox appliance where I want a non-root user to be able to execute a particular script with root ...
1
vote
0answers
10 views

openvassd hanging

I have a problem with openvassd hanging while starting: connect(6, {sa_family=AF_LOCAL, sun_path="/tmp/redis.sock"}, 110) = 0 fcntl64(6, F_GETFL) = 0x802 (flags O_RDWR|O_NONBLOCK) ...
0
votes
1answer
39 views

Are NetBSD provide digital signatures for official ISO images and binary packages?

I just install NetBSD in from ISO image inside VirtualBox. Official source ISO media contains only MD5/SHA512 sums. Similarly pkg_add binary packag repository contains only SHA512 sums. Both FTP ...
3
votes
1answer
31 views

How to limit connections to OpenSSH server to using private keys necessarily with passphrase?

Is there any way to configure OpenSSH (/etc/ssh/sshd_config) server to allow private keys necessarily with passphrase?
3
votes
1answer
40 views

groupadd -p Not Recommended?

I have a question about groupadd, specifically with password (-p). It says it is not recommended, "This option is not recommended because the password (or encrypted password) will be visible by users ...
2
votes
2answers
67 views

Safe execution of cat command without executing arbitrary code

I do this little file based on a combination of hexadecimal, that can broke cat and the terminal showing the file with cat, reset does not worked anymore, it is maybe putting cat in a kind of loop? ...
1
vote
1answer
35 views

Is there an additional option to display hidden command on the terminal?

Copy and pasting from a website to the terminal is very harmful , there are an example here You past the following line :ls /some/thing/much/too/long/to/type/ , by pressing Enter the following ...
1
vote
1answer
38 views

Install ModSecurity Commercial Rules

We bought the ModSecurity commercial rules, but I am not having success installing them. I tried using the ModSecurity dashboard, but it seems that it is not working. Even though I get a message ...
0
votes
1answer
271 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
1answer
14 views

Standard Package updates of selinux-policy-*

I am wondering if after installing an update of a selinux-policy-* package you are using, do you need to reset all the labels in the system (i.e. fixfiles onboot) in order to keep the policy effective?...
4
votes
1answer
145 views

Executing commands in an elevated bash process by writing to the standard input of its parent script process

I have a simple bash script bash.sh that starts another bash instance using pkexec. #!/bin/bash bash -c 'pkexec bash' When executed this shows a prompt for the user to enter their password. The ...
4
votes
2answers
2k views

Disadvantages to having www-data able to log in

I run a tiny web server basically just for hosting small data projects and files. This server has a public IP address. I would like to be able to FTP in and upload files directly to /var/www/*, and ...
4
votes
2answers
1k 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 ...
4
votes
1answer
2k 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 ...
0
votes
0answers
56 views

Can we run apache on a non-root account?

Apache is started by the root user, then switches to the user defined by the User directive; is there any chance where we can change this default behavior? Apache should start using a non-root account ...
7
votes
1answer
989 views

Opening port 80 but remain secure

I have a standard installation of Ubuntu 10.04, and have installed the LAMP stack so I can do some web development locally. On my router I have opened port 80 so I can develop with external services ...