Questions tagged [security]

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.

Filter by
Sorted by
Tagged with
0
votes
1answer
15 views

iptables block fragmented flow that contain specific string

I want to block traffic that contain specific string "anypattern". I know that the right iptables rule for that is: iptables -m string --algo bm --string "anypattern" -j DROP The problem that the ...
1
vote
1answer
51 views

'pass': Easiest way to synchronize the password-store between multiple machines

I moved to the pass password manager and I'm trying to integrate it as well as possible into my workflow. However, I'm not familiar with deeper synchronization/version-control concepts (git, password ...
0
votes
1answer
98 views

Why we need to set no_new_privs while before calling SECCOMP_MODE_FILTER?

At the man page I read the following line: cause an attempt to use setuid(2) to set the caller's user IDs to nonzero values to instead return 0 without actually making the system call I can't ...
0
votes
0answers
58 views

How to intercept any call to the kernel to spawn a process

I am attempting to make a program that is a system security watchdog. Any processes or ports that are not supposed to be open will be closed by the watchdog to mitigate a breech in security. I'm ...
1
vote
0answers
56 views

Change ptrace_scope temporarily for a specific user

ptrace_scope is a sysctl value (/proc/sys/kernel/yama/ptrace_scope) that prevents the use of ptrace on non-child processes when set to 1. This is generally considered good security practice. ...
0
votes
0answers
9 views

centOS 7 access denied when logging on kerberized environment

When I am trying to log in to one of my hadoop nodes running centos 7. I am receiving a 'access denied' error. Typically, in these situations, I login as the local admin for the box, go to /tmp and ...
1
vote
2answers
180 views

Historically, what was the first OpenBSD remote hole?

On: https://www.openbsd.org/ I can see: Only two remote holes in the default install, in a heck of a long time! I understand the concept what are they pointing out, since other OSes have ...
0
votes
1answer
122 views

List all keys with SHA-1 in the gpg keyring

After reading a paper about "First Chosen-Prefix Collision on SHA-1 and Application to the PGP Web of Trust", I wonder how many SHA-1 keys are left in specific key rings. How to list all keys in a ...
1
vote
1answer
100 views

Is there an interactive firewall on Linux, one that gives popup on anything trying to connect to anything?

I used ZoneAlarm and a few other programs for a long time on Windows, just because I could control anything from system services to any software connecting to any IP address. I don't find the idea of ...
0
votes
0answers
26 views

Detecting cleartext & metadata leaked by software

I'd like to test several Linux programs and see what kind of unencrypted data & metadata they leak to/from the internet (e.g. imagine living in a country where your political or religious beliefs ...
0
votes
1answer
91 views

How to decrypt file that was symmetrically encrypted using GPG?

I've created and symmetrically encrypted a file using GPG: touch test.txt && echo 'test' >> test.txt gpg --output test.txt --symmetric test.txt But now I cannot figure out how to ...
0
votes
1answer
98 views

How to set selinux labels for a folder hierarchy accessed server side by NFS, Apache, and SaMBa daemons simultaneously?

The Mandatory Access Controls or MAC labels are different for NFS which are different for httpd, and different yet again for SaMBa. What is the proper way nowadays to label a SINGLE shared filesystem ...
-1
votes
1answer
33 views

Should we have a lot shells in our Ubuntu server?

I have these shell in my VM # /etc/shells: valid login shells /bin/sh /bin/bash /bin/rbash /bin/dash /usr/bin/tmux /usr/bin/screen /bin/zsh /usr/bin/zsh Is it a good thing ? Should I safely remove ...
0
votes
1answer
81 views

I am looking for a way to protect myself from a possible evil maid attack

I found a way that you can move the boot loader to a USB. Then in case of any changes I thought about checking hash of the USB after boot. Since hard drive will be encrypted, an evil maid can't know ...
0
votes
2answers
57 views

Can a program get root access if it gets the password?

If there's only 1 user on a system with sudo permission, can another program that ran by the user get root permission without the user knowing it if it has the sudo password?
3
votes
1answer
83 views

Solaris: is possible to permit root login on some terms?

I have a server with some serial ports. One is /dev/console, another is /dev/term/b(the ttyS1 under linux and the COM2 under dos). I want root to login under /dev/term/b but.. myserver termb login: ...
-2
votes
2answers
170 views

How to restrict anyone (Root user also) to modify file in Linux?

I am developing one security base software for LINUX platform using C and CPP. I want to restrict all users even ROOT user also to modify the file. i.e No one can modify the file. Modifying means No ...
0
votes
0answers
33 views

Unauthorized device is connected to my terminal [duplicate]

I connected my MacBook in a public cafe network at around 15:24 and when I opened terminal at 16:36 I saw that the terminal said "deniz@Galaxy-A70 - %" where it normally says "deniz@MacBook Pro - %". ...
0
votes
0answers
18 views

Make https request with HAProxy without explicitly mentioning certificates?

Why? Some app started making annoying authentication verification that work with the region. Every time I travel, and I login from another country, I have to go through a very annoying process of ...
4
votes
1answer
272 views

Disable password on linux user with command

Based on /etc/shadow(5) documentation on the second (password) field: encrypted password If the password field contains some string that is not a valid result of crypt(3), for instance ! or *...
-2
votes
1answer
91 views

Mount options for increased security

I am aiming to increasing security of our Linux server with nodev, nosuid and noexec mount options. Please find the attached image about showing my fstab file. My question is about /boot written in ...
1
vote
1answer
133 views

What is the difference between pam_faillock and pam_tally2?

To block a user after a preset number of failed login attempts, one would use a module like pam_tally2 or pam_faillock. What is the difference between these two? Which one should I use when?
0
votes
0answers
29 views

Is it possible to encrypt traffic if I have only CA certificate?

I have simple secure (I guess) Mosquitto sever described in my previous question. Client machine has no any keys or certificate installed except single ca.crt certificate file generated and taken ...
1
vote
1answer
208 views

Verify installed rpm packages signatures

I'm interested in checking the integrity of all installed rpm packages on the system. In case I have the rpm file itself, I'll run rpm -Kv PACKAGE.rpm, but what can I achieve the same goal if I the ...
0
votes
0answers
20 views

Torify Clearnet Website

I want to torify existing HTTPS domain website into my Tor Hidden Service, if possible by specific outgoing IP Interface. I think squid would be the perfect way. Tried already nginx reverse proxy, ...
3
votes
3answers
165 views

Why can't entire kernels be patched live?

Over the past few years, various live kernel patching techniques have become popular among sysadmins who strive to ensure the highest possible uptimes for their systems. For that process to be ...
0
votes
0answers
35 views

Menu to disable/enable trust for USB/thunderbolt devices

Is there a way to enable/disable trust for USB/thunderbolt devices? Sort of like when you plug something in, it asks you whether you want to trust the device for data? I remember seeing a video where ...
0
votes
1answer
47 views

Add ssh authorized key and hide it in the authorized_keys?

Is it possible to add an ssh key to a system and make hidden (at least at first glance) from the user? UPD: Recently I was participating in a CTF and had access to another team's machine. I wanted to ...
0
votes
0answers
46 views

How to interpret the output of the “who” cmd? - wrong date, non-existing user

On a SLES11, I can see the following output: $ who | grep -i FOOBARUSER FOOBARUSER ::ffff:127.0.0.1:3 Mar 2 09:52 (::ffff:127.0.0.1::ffff:127.0.0.1:3) FOOBARUSER ::ffff:127.0.0.1:3 Mar 2 09:52 (:...
2
votes
0answers
102 views

Security issues for passing credentials over a UNIX socket

UNIX sockets often have a mechanism to authenticate their peer processes. However, there is a requirement for care in order to avoid confused deputy attacks. Linux, for example, has two ways to pass ...
1
vote
1answer
40 views

Which services read the /etc/securetty configuration file?

Which programs / services are parsing contents of /etc/securetty configuration file?
3
votes
1answer
285 views

Why do I get a warning for the sudoers.d when doing an audit with Lynis?

I stumbled upon Lynis - a security auditing tool for linux - and ran it on my Raspberry Pi to see if I could harden it a bit more. I got one warning in the Authentication group that confuses me. - ...
1
vote
1answer
116 views

Debian 10 su command to existing user as root without password

I just installed a brand new VM with Debian 10 (buster) and joined it to our active directory using pbis. what I encountered now is, that: as the root user, I can su to every other available user ...
0
votes
1answer
36 views

Can a Linux partition unnoticeably create files in another partition and, if, how can I prevent it?

Is it possible that my Linux partition creates files in another partition with me not noticing it? If yes, how to prevent it? Background: Manjaro partition encrypted, bootloader on Manjaro, swap ...
1
vote
0answers
37 views

Is there something like HTTP Digest access authentication for SSH?

Apparently, SSH does send (albeit using an encrypted connection) the client's login password to the server if password authentication is being used instead of a pair of public and private keys: Does ...
0
votes
2answers
139 views

How often to update Arch Linux? [closed]

Outside of announcements about critical security flaws, is a period of one month between Arch Linux updates (pacman -Syu) dangerous in terms of security?
0
votes
0answers
93 views

sshd_config: using only the most secure ciphers, KexAlgorithms, MACs

In /etc/ssh/sshd_config I am using the following configuration settings. Can this be further hardened? KexAlgorithms curve25519-sha256@libssh.org MACs hmac-sha2-512-etm@openssh.com,hmac-sha2-512 ...
0
votes
1answer
20 views

Centos SSH & SFTP user restriction to specific directories

I am managing a server running Cantos 7. Some users login to the server via ssh/sftp for development. For them i have created a user devel. For security reasons, i need to confine them to certain ...
36
votes
14answers
5k views

How can I speed up secure erasing of a disk?

I need to securely erase harddisks from time to time and have used a variety of tools to do this: cat /dev/zero > /dev/disk cat /dev/urandom > /dev/disk shred badblocks -w DBAN All of these ...
2
votes
1answer
44 views

RKHUNTER does not recognise common options

At the bottom of rkhunter.conf (I also tried placing it separately in rkhunter.conf.local), and after checking for invisible chars, Unknown configuration file option: CRON_DAILY_RUN="false" ...
0
votes
1answer
490 views

How to implement security profiles during installation of CentOS 8?

I am new to the Linux environment and I found CentOS to be a stable and secure operating system. I do not have much knowledge about the security profiles and how well do they protect the operating ...
4
votes
1answer
67 views

should I leave modifications on /etc/default/intel-microcode and changes in revision number?

I have a quad-core intel machine having i5-7400 CPU @ 3.00GHz . Recently, Intel introduced a new bunch of updates for machines affected by the spectre vulnerabilities. One can see the changelog.gz ...
0
votes
2answers
30 views

Recommendation for securing a external hard disk

I have lost dates (film files and docs) on my external hard disk with dd (hd was on ext4 format, 2TB and had only videos and some files). I "restore" them with PhotoRec, with bad quality... Because I ...
0
votes
0answers
39 views

Securing a private package repository for Debian

I’m setting up a private binary package repository for an embedded device we’ve made. Want to make it secure despite users are allowed to check for, and install, software updates. I’ve generated the ...
0
votes
0answers
18 views

SSSD configured for optimal security Kerberos only no need for LDAPS?

SSSD configured for optimal security Kerberos only no need for LDAPS? I want to ensure I have configured our SSSD for optimal security. Any insight would be appreciated. Should I add any values? ...
1
vote
1answer
48 views

Xorg: Having authenticated in X as a remote user allows me to have access to another users' applications?

I'm trying to run a docker container (for security reasons) from which I want to see a GUI application. I'm between two options at the moment, I'm not sure if I should forward its traffic to my X ...
1
vote
1answer
47 views

Determining source of ulimit change

I have a server built with AWS OpsWOrks, so everything is in configuration. There is a process whose ulimit is set to 4096, as checked from /proc/$PID/limits. This process runs as root. I ran the ...
0
votes
0answers
112 views

Unable to set right access capabilities

I have a process with file capabilities set. This process forks (clone) a child, which should inherit the set capabilities. Actually, the strace below (20897 is the process started with file ...
0
votes
1answer
33 views

Are there drawbacks (security or otherwise) to using 'su <user>' into a lesser-priveleged user to start a web application?

My goal is to manage the startup of a number of applications with an application executed by a user with elevated permissions. The plan is to have the startup manager (a node.js script using require('...
1
vote
1answer
562 views

fprint doesn't find my laptop's fingerprint device but lsusb does?

So when i use lsusb i can find the fingerprint device, the name of it is Generic goodix fingerprint device and my laptop is lenovo thinkpad 530s considering that lsusb can find it then why can't ...

1
2
3 4 5
44