The Mac OS X system temporary folder (/tmp or /private/tmp) may occasionally have its permissions changed by Symantec Endpoint Protection (SEP for Mac).
The SEP for Mac SymDaemon process will create and administer its own subfolders and files in the /tmp directory and occasionally may mistakenly adjust permissions on the parent.
This issue has been fixed in SEP 12.1 RU6 MP2. Download the latest version of Symantec Endpoint Protection and upgrade SEP for Mac.