The news of the flaw apparently isn't new to the USPS. The researcher claims he told officials there of the issue more than a year ago but didn't get any response, Clark.com reported.
USPS officials said the issue has been corrected, but only after the expert, Brian Krebs, asked employees about it.
Informed Visibility allows users to track mail end-to-end.
Krebs said the vulnerability was due to a "wildcard" search, meaning search results could be return for all records of a data set, not pared down to specific terms. No hacking tools were needed to view the information other than being able to view and change data elements processed by browsers like Chrome or Firefox.
Since being alerted to the issue, the USPS has now introduced a validation step to prevent changes by an unauthorized person, Krebs said.
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