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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1answer
24 views

Script samba password but securely

I want to script the addition on a samba user and the password. I have seen solutions similar to the one here Piping password to smbpasswd echo -ne "$PASS\n$PASS\n" | smbpasswd -a -s $LOGIN but ...
75
votes
6answers
47k 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 ...
4
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1answer
38 views

Monitoring ARP Poisoning

How to monitor ARP poisoning? These few days my internal website that can be accessed locally has weird image replacing every images on the site for few seconds (it got back to normal after ...
11
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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 ...
62
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20answers
10k views

Root access that can't change root password?

We are having a little problem on a server. We want that some users should be able to do e.g. sudo and become root, but with the restriction that the user can't change root password. That is, a ...
5
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4answers
3k views

Force Firefox to remember passwords on particular sites

Usually, when I log into a website with username and password, Firefox asks whether it should remember the login details. When I click yes, next time I visit the website, the username and password ...
11
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7answers
3k views

When does the Puppy linux security model make sense?

I have just spent a few hours playing with Puppy linux, which has some very nice features, but there are some things about its approach to security (at least the default settings) that worry me: It ...
4
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0answers
104 views

Unexplained files found in home folder

For background information, I'm running openSUSE 13.2 and KDE 5. Today I found a number of unexplained files and folders in my home folder which state they've been edited 3 days ago. I do not ...
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0answers
33 views

Allowing sudo kill for remote user for recovery purpose. Security implications?

I'm planning to create user allowed to SSH in and with right to sudo kill in case something disables local terminal/keyboard/display etc. Would probably add ps and/or htop to the list, as well. I ...
1
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2answers
76 views

Too many open ports in Debian 8

The IT department has given me 3 virtual servers with Debian 8 for my area, which I will manage (but they have some monitoring tools). Starting Nmap 6.40 ( http://nmap.org ) at 2015-05-11 13:33 ART ...
0
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1answer
42 views

What are the differences between sudo and the use of groups?

I know these are tools used for improving security. But what I would like to know is what they are and how they work?
19
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10answers
5k views

How to create strong passwords in Linux?

I wonder how I can create strong passwords on Linux (for both normal and admin users) and if there are specific programs to do that.
4
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2answers
110 views

how to prevent a buffer from swap

this question is specific to Unix and Linux. but it is programming and security, too. my program will get a clear password or decryption key by one of a few ways (decrypting a password file, asking ...
1
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0answers
24 views

Multiple DHCP Offers - Which is selected? [closed]

I have created a testing scenario in VMWare for a man in the middle attack using DHCP spoofing. It's for a college project. Windows 8 machine bridged to host adapter Kali linux bridged to host ...
6
votes
3answers
133 views

What bad things could happen if we don't use sudoedit?

We know it's safer* to use sudoedit, but what bad things can happen if we have the following in sudoers? Cmnd_Alias FOO = /bin/ed, /usr/bin/ed, /usr/bin/vi foouser LOCALHOST = NOPASSWD: NOEXEC: FOO ...
2
votes
1answer
349 views

Hiding an encrypted folder in a shared system without root access (unshare -m)

I'm a graduate student trying to use a cluster at my university. These machines are shared, so I want to protect the source code I use (I signed a NDA, so I'm scared about publishing the code by ...
10
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1answer
226 views

D-Bus authentication and authorization

I'm trying to set up remote access to D-Bus, and I don't understand how authentication and authorization are (not) working. I have a D-Bus server listening on an abstract socket. $ echo ...
1
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0answers
56 views

Where to put the SElinux policy to allow acpid shutdown the system?

I'm using Centos7 minimal. I've installed acpid and the daemon is running. When I hit the power button, I get the following in /var/log/messages May 2 18:52:53 localhost systemd-logind: Power key ...
0
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1answer
209 views

Permission denied tmp dir on STIG RHEL

I am writing a program for a DISA STIG version of Red Hat Linux 6.5. I wrote a shell script to do self extracting on the program and when it self extracts put temporary files in the tmp directory that ...
0
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0answers
58 views

logging wrong passwords in /var/log/auth.log

/var/log/auth.log logs (among other things) failed login attempts to my debian linux. I was wandering if it is possible to ask it to log the password that was used in the failed attempt. This is ...
0
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1answer
348 views

SC_ERR_NOT_SUPPORTED(225) with Suricata on CentOS 6.5

I have just installed installed Suricata 2.0.3 RELEASE on CentOS 6.5. I try running it with sudo suricata -c /etc/suricata/suricata.yaml -i eth0 and get the following warning <Warning> - ...
-2
votes
2answers
41 views

Can I restrict the root to a single browser?

I want to be able restrict myself to firefox. I do not want to be able to use any other browser. So if I install chrome or any other browser, I don't want them to work on my Linux machine. Here is ...
2
votes
1answer
65 views

Understand HMAC authentication in case of site-to-site OpenVPN tunnel

I have a very simple OpenVPN setup where OpenVPN server is started with openvpn --ifconfig 10.10.10.1 10.10.10.2 --dev tun and client is started with openvpn --ifconfig 10.10.10.2 10.10.10.1 --dev tun ...
0
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1answer
40 views

What changes my boot partition and how to prevent it?

As an another countermeasure against security threats I wrote a little script that computes MBR and boot checksum and then compare it to the old one. As long as the computer is running this is OK, but ...
2
votes
0answers
78 views

Security of sudo not asking for a password after the first time

After using sudo and entering a password to do so, sudo remembers that we have entered a password and we do not have to enter a password the next time we use it. I am concerned about the possibility ...
81
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3answers
19k views

How do I recover from the Heartbleed bug in OpenSSL?

CVE-2014-0160 a.k.a. Heartbleed is a vulnerability in OpenSSL. It looks scary. How do I determine whether I am affected? If I'm affected, what do I need to do? Apparently upgrading isn't enough.
2
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1answer
211 views

Exploit FOUND with clamav on Fedora 21 in Oracle's java

I'm scanning one of my systems with Clamav like this: $ clamscan -r -i --remove --max-filesize=4000M --max-scansize=4000M \ --exclude=/proc --exclude=/sys --exclude=/dev ...
0
votes
1answer
71 views

How can I study Linux, in and out? [closed]

My team and I will soon begin studying and practicing for the nation-wide Cyber Patriot program. As I'm famed for being our "Linux guy", I would really like to improve my knowledge on the subject. ...
1
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1answer
33 views

Where to verify and review various packages before installing them

I am new to Unix/Linux and corrently setting up a Debian Wheezy server for my domain name. Here and there I find useful tutorial on how to do this-and-that, but I am not sure where I can find a ...
4
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2answers
111 views

Did this tutorial block pings to my server?

I am a programmer teaching myself linux admin stuff. I followed this tutorial to setup a firewall on a VPS. As a part of that tutorial, I block all traffic except for web traffic and SSH traffic. I ...
0
votes
1answer
47 views

UNIX Account management

Would like to know if there's some opensource solution aimed to manage and administer system authentication and RSA keys for staff, contractors and clients across the organization. My systems to ...
2
votes
1answer
72 views

How to scan a directory with a space in its name with maldet

I'm trying to scan some directories with Linux Malware Detect (command-line command maldet): maldet -a /SOMETHING\ 1/ But I get: maldet(13857): {scan} invalid path /SOMETHING 1/ I've tried ...
3
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3answers
135 views

Remove passphrase from private key and set specific file mode

If I set a passphrase on my private key like so: openssl rsa -des -in insecure.key -out secure.key and I remove the passphrase like so: openssl rsa -in secure.key -out insecure.key then my ...
1
vote
1answer
58 views

wheel groups and permissions

I'm new to a lot of things Linux, so this might be basic stuff. We're thinking about setting up a wheel group and removing permissions from root. Not even sure that's possible. We are having a ...
1
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1answer
453 views

Unable to set capability CAP_SETFCAP by user

The question is about capabilities. I need to allow user to set capabilities using setcap. When I call it by root all goes fine, eg $ sudo setcap cap_dac_override,cap_dac_read_search+ep ./bin_file $ ...
0
votes
1answer
28 views

Sanitise bash arguments

I have a script which takes user input and does a lot of things. One thing which I am worried about is it takes a file name and removes that file. e.g. rm -rf $arg1. A user could technically input / ...
6
votes
1answer
199 views

When running 'su - username', pam_group doesn't add additional groups from /etc/security/group.conf but sshd login does?

I am having trouble determining why su doesn't behave as the PAM configuration would imply. In short, using su to become another user should load secondary groups according to PAM configuration, but ...
4
votes
1answer
134 views

SSH server listening on multiple ports with passwordless access not allowing connections to second port

I have my Synology NAS running an SSH server listening on the default port 22 and I set up passwordless authentication with a public/private key and a passphrase: From sshd_config: ...
7
votes
2answers
496 views

Myth or reality: SELinux can confine the root user?

I read or heard somewhere (maybe in LinuxCBT's SELinux course; but I'm not sure) that there are online Linux servers, for which the password of the root user is also given. The Linux server is ...
0
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1answer
355 views

How to import the official Tor GPG keys?

I am trying to install the latest Tor Browser Bundle on Arch Linux: $ makepkg --syncdeps --install [...] ==> Verifying source file signatures with gpg... tor-browser-linux64-4.0.8_en-US.tar.xz ...
1
vote
1answer
73 views

LDAP Force Password Change Through HTTPS

We have a "master" server running Suse Enterprise with LDAP that controls user's access to our systems. We want to implement a 90 day expiration policy, but the issue is that most of our servers are ...
0
votes
0answers
30 views

Bro-IDS CSV conversion

I have Bro-IDS currently operating under Centos 7. I need to convert the output to CSV format. The documentation that I have seen on this is not clear to me. Has anyone done this successfully? I have ...
1
vote
2answers
31 views

How do I install programs in /usr/local if they shouldn't be compiled by root?

Somewhere in the back of my brain is the memory of reading a cautionary internet voice warning against compiling (i.e. running make) as the root user. Perhaps it's something like this story ...
1
vote
1answer
75 views

Dubious entry in logwatch

Today I found the following in the daily logwatch of my debian server: --------------------- Connections (secure-log) Begin ------------------------ **Unmatched Entries** sg: user 'root' (login ...
0
votes
0answers
29 views

Snort alerts analysis (web interface)

I have a question about Snort (or maybe any other IDS/IPS, any working solutions would be ok). The goal is to set up some web interface providing a way to view the whole TCP stream packets of each ...
1
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0answers
20 views

Unable to use wifi card after putting it into monitor mode

I'm trying to monitor 802.11 Reauthentication requests and responses made from the DS to the STA. The problem is when using airmon-ng to put the card into monitor mode, the interface is no longer ...
0
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2answers
55 views

FreeBSD 10 and ZFS: Methods for encrypting files

I'm in the process of setting up a FreeBSD 10 server on a KVM vserver. I'm really new to FreeBSD in general (coming from Debian Linux). I installed the system choosing ZFS with encrypted root volume ...
4
votes
2answers
3k 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 ...
9
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3answers
15k views

Moving /var, /home to separate partition

I am attempting to move some folders (such as /var and /home) to a separate partition after reading this guide: 3.2.1 Choose an intelligent partition scheme I was able to move one folder ...
2
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1answer
34 views

Are there any loopholes in IP restricting sshd?

Say that i want to only allow username/password logins on my private network, but restrict all external sources on to key/cert login. I would do something like this: RSAAuthentication yes ...