[SOLVED] Nmap not working when implemented in crontab

joe_2000 · 02-15-2019, 09:36 AM

Quote:

Originally Posted by lgrech25

Yes the script is executable. In fact it works perfectly fine. Only in crontabs it doesn't work

-rwxrwxrwx 1 admin19 admin19 104 Feb 15 16:22 HostDiscovery

So what does /tmp/logfile say after the modification as per my previous post?

lgrech25 · 02-15-2019, 09:40 AM

It worked Guys Thanks a lot. After changing the directory and implementing everything in the sudo crontab -e. It updated 2/3 minutes after because of the namp process. Sorry for bothering you a lot

michaelk · 02-15-2019, 09:43 AM

crond will detect when /etc/crontab has changed and reload the file so there is no need to restart the service.

I agree with joe_2000 that it should work and it does from my debian system. The changes I made were to add a space between -d and
' ' in the cut command and add an absolute path to the output file.

Code:

*/5 * * * * root /usr/bin/nmap -O 192.168.0.1-253 | grep 'Nmap scan' | cut -d ' ' -f5 > /tmp/HostList

joe_2000 · 02-15-2019, 09:43 AM

Quote:

Originally Posted by lgrech25

It worked Guys Thanks a lot. After changing the directory and implementing everything in the sudo crontab -e. It updated 2/3 minutes after because of the namp process. Sorry for bothering you a lot

Cool. So in summary, the original problem was that the output file ended up in some other location than you expected? Probably /root ?

Either way: It's good advice from TBOne to use crontab -e as this will also do syntax checking on your crontab entries and complain if the syntax is wrong.

joe_2000 · 02-15-2019, 09:45 AM

Quote:

Originally Posted by michaelk

The changes I made were to add a space between -d and
' ' in the cut command and add an absolute path to the output file.

imho the space is not required

michaelk · 02-15-2019, 09:49 AM

It shouldn't, when I tested the command I had a to fix a typo...

joe_2000 · 02-15-2019, 09:52 AM

Quote:

Originally Posted by michaelk

It shouldn't, when I tested the command I had a to fix a typo...

Code:

$ echo "foo bar" | cut -d' ' -f 2
bar

...runs fine over here :-)

jpollard · 02-16-2019, 04:24 AM

Quote:

Originally Posted by lgrech25

Yes the script is executable. In fact it works perfectly fine. Only in crontabs it doesn't work

-rwxrwxrwx 1 admin19 admin19 104 Feb 15 16:22 HostDiscovery

rwxrwxrwx is a security fail as it allows anyone to takeover your account.