| secure /tmp partition |
Several script languages like PHP, holds temporary files like session,upload and cache on the /tmp partition on Linux systems. İf the attacker has an access to this folder then those scripts can be run from this point so with this way, all system files can be reached or accessed by root. To block running of files which are in the /tmp partition, it must not be given run permission while mounting /tmp partition. To do this process, you have to choose /tmp partition as seperate partition while installaing the system. Enter this command in the command line to check this setting: df -h # or
mount Enter this command: [root@xxx ~]# df -h
Filesystem Size Used Avail Use% Mounted on /dev/mapper/VolGroup00-LogVol00 2.9G 820M 1.9G 30% / /dev/mapper/VolGroup00-LogVol02 2.9G 288M 2.4G 11% /tmp /dev/mapper/VolGroup00-LogVol04 7.8G 3.8G 3.7G 51% /var /dev/mapper/VolGroup00-LogVol05 44G 35G 6.6G 85% /hsphere /dev/mapper/VolGroup00-LogVol03 4.8G 908M 3.6G 20% /usr /dev/sda1 99M 36M 58M 39% /boot tmpfs 2.0G 0 2.0G 0% /dev/shm If you can not see a seperate /tmp partition like in the example, create a new 250 MB /tmp partition by applying steps below. If there is a /tmp partition then follow with the solution 2: Solution 1: cd /dev/
dd if=/dev/zero of=Tmp bs=1024 count=250000 mkfs -t ext3 /dev/Tmp cd / cp -aR /tmp /tmp_backup mount -o loop,noexec,nosuid,rw /dev/Tmp /tmp cp -aR /tmp_backup/* /tmp/ chmod 0777 /tmp chmod +t /tmp Add information of the newly created partition into the /etc/fstab in order to make it available after next boot. /dev/Tmp /tmp ext3 loop,rw,nosuid,noexec 0 0
If you already have /tmp partition, please apply the below steps. Solution 2: /etc/fstab içerisindeki /tmp defaults değerini değiştirin /dev/VolGroup00/LogVol02 /tmp ext3 defaults 1 2
/dev/VolGroup00/LogVol02 /tmp ext3 rw,nosuid,noexec 1 2
Change defaults region as rw,nosuid,noexec then save and exit. Remount /tmp partition in order to make changes available immediately: mount -oremount loop,rw,nosuid,noexec /tmp
Navigation •  •  WARNING: This document is prepared for CentOS5.5 but expected to be compatible with other versions and differs some commands or command paths. Please, check the used services before applying these steps. |
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