Tag: security

install openvas in centos8

sed -i 's/enforcing/disabled/g' /etc/selinux/config

reboot

dnf update

yum config-manager --set-enabled PowerTools
yum install epel-release

wget -q -O - http://www.atomicorp.com/installers/atomic |sh

yum install openvas

openvas-setup

More : https://github.com/Atomicorp/gvm

  • Cronjob to update CVE database
10 1 * * * /usr/sbin/greenbone-nvt-sync > /dev/null
10 2 * * * /usr/sbin/greenbone-scapdata-sync > /dev/null
10 3 * * * /usr/sbin/greenbone-certdata-sync > /dev/null

Openvas API:


gvm-cli --gmp-username USRENAME --gmp-password PASSWORD socket --sockpath /var/run/gvm/gvmd.sock --xml "<get_tasks/>"

gvm-cli socket --sockpath /var/run/gvm/gvmd.sock --xml "<get_version/>"

Special File Permissions in linux setuid, setgid, sticky bit

setuid permission:

When program is executed with setuid permission it will executed as owner of that program.

-rwsr-xr-x. 1 root root 27856 Aug  9  2019 /usr/bin/passwd

as passwd has setuid set that’s why normal user can reset their password

#exec will be as owner user
chmod u+s  file_name 

#exec will be as owner user
chmod 4750   file_name

setgid permission:

When program is executed with setgid permission it will executed as group owner of that program.

-r-xr-sr-x. 1 root tty 15344 Jun 10  2014 /usr/bin/wall

as wall has setgid enabled it has all the permission as group tty has.

chmod u+g  file_name 
chmod 2700   file_name

Sticky bit:

Owner of files and directory and root can only delete the file when sticky bit is set.

drwxrwxrwt.  16 root root 4096 Oct 10 10:10 tmp

all linux /tmp directory has sticky bit enabled.

chmod +t /tmp

NOTE: Capital S,T displayed when user does not have execute permission on that file