If you are renting a server then chances are everything is lumped in \/ and a small amount partitioned for \/boot and some for swap. With this current setup, you have no room for making more partitions unless you have a second hard-drive. Learn how to create a secure \/tmp partition even while your server is already up and running.
\nRecently, I found out it would be worthwhile to give \/tmp it\u2019s own partition and mount it using noexec- This would protect your system from MANY local and remote exploits of rootkits being run from your \/tmp folder.<\/p>\n
What we are doing it creating a file that we will use to mount at \/tmp. So log into SSH and SU to root so we may being!<\/p>\n
code:<\/p>\n
cd \/dev<\/em><\/p><\/blockquote>\n
Create 100MB file for our \/tmp partition. If you need more space, make count size larger.<\/p>\n
code:<\/p>\n
dd if=\/dev\/zero of=tmpMnt bs=1024 count=100000<\/em><\/p><\/blockquote>\n
Make an extended filesystem for our tmpMnt file<\/p>\n
code:<\/p>\n
\/sbin\/mke2fs \/dev\/tmpMnt<\/em><\/p><\/blockquote>\n
Backup your \/tmp dir- I had mysql.sock file that I needed to recreate the symbolic link for. Other programs may use it to store cache files or whatever.<\/p>\n
code:<\/p>\n
cd \/<\/em><\/p><\/blockquote>\n
code:<\/p>\n
cp -R \/tmp \/tmp_backup<\/em><\/p><\/blockquote>\n
Mount the new \/tmp filesystem with noexec<\/p>\n
code:<\/p>\n
mount -o loop,noexec,nosuid,rw \/dev\/tmpMnt \/tmp<\/em><\/p><\/blockquote>\n
code:<\/p>\n
chmod 1777 \/tmp<\/em><\/p><\/blockquote>\n
Copy everything back to new \/tmp and remove backup<\/p>\n
code:<\/p>\n
cp -R \/tmp_backup\/* \/tmp\/<\/em><\/p><\/blockquote>\n
code:<\/p>\n
rm -rf \/tmp_backup<\/em><\/p><\/blockquote>\n
Now we need to add this to fstab so it mounts automatically on reboots.<\/p>\n
code:<\/p>\n
pico -w \/etc\/fstab<\/em><\/p><\/blockquote>\n
You should see something like this:
\ncode:
\n\/dev\/hda3 \/ ext3 defaults,usrquota 1 1
\n\/dev\/hda1 \/boot ext3 defaults 1 2
\nnone \/dev\/pts devpts gid=5,mode=620 0 0
\nnone \/proc proc defaults 0 0
\nnone \/dev\/shm tmpfs defaults 0 0
\n\/dev\/hda2 swap swap defaults 0 0<\/em><\/p>\nAt the bottom add
\ncode:<\/p>\n\/dev\/tmpMnt \/tmp ext2 loop,noexec,nosuid,rw 0 0<\/em><\/p>\n
(Each space is a tab)
\nSave it!
\nCtrl + X and Y<\/em><\/p><\/blockquote>\nYour done- \/tmp is now mounted as noexec. You can sleep a little bit safer tonight. I created a hello world c++ and compiled it then moved it to \/tmp. Upon trying to run it (even chmod +x\u2019ed), it gives the following error:<\/p>\n
code:
\nbash: .\/a.out: Permission denied<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"If you are renting a server then chances are everything is lumped in \/ and a small amount partitioned for \/boot and some for swap. With this current setup, you have no room for making more partitions unless you have a second hard-drive. Learn how to create a secure \/tmp partition even while your server […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[20],"tags":[],"_links":{"self":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/954"}],"collection":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=954"}],"version-history":[{"count":2,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/954\/revisions"}],"predecessor-version":[{"id":956,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/954\/revisions\/956"}],"wp:attachment":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=954"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=954"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=954"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}