Successful su for proxy by root

[scar]

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i have been monitoring my /var/log/auth.log lately and i noticed these
few entries are showing up about once per day.  can anyone shed light on
what is causing it?  who is user proxy?  thanks

Feb 14 07:54:51 ubuntu-desktop su[24751]: Successful su for proxy by root
Feb 14 07:54:51 ubuntu-desktop su[24751]: + ??? root:proxy
Feb 14 07:54:51 ubuntu-desktop su[24751]: pam_unix(su:session): session
opened for user proxy by (uid=0)
Feb 14 07:54:52 ubuntu-desktop su[24751]: pam_unix(su:session): session
closed for user proxy

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