A free new service from the U.S. Postal Service that provides scanned images of incoming mail before it is slated to arrive at its destination address is raising eyebrows among security experts who worry about the service’s potential for misuse by private investigators, identity thieves, stalkers or abusive ex-partners. The USPS says it hopes to have changes in place by early next year that could help blunt some of those concerns.
The service, dubbed “Informed Delivery,” has been available to select addresses in several states since 2014 under a targeted USPS pilot program, but it has since expanded to include many ZIP codes nationwide, according to the Postal Service. U.S. residents can tell if their address is eligible by visiting informeddelivery.usps.com.

Image: USPS
According to the USPS, some 6.3 million accounts have been created via the service so far. The Postal Service says consumer feedback has been overwhelmingly positive, particularly among residents who travel regularly and wish to keep close tabs on any mail being delivered while they’re on the road.
But a review of the methods used by the USPS to validate new account signups suggests the service is wide open to abuse by a range of parties, mainly because of weak authentication and because it is not easy to opt out of the service.
Signing up requires an eligible resident to create a free user account at USPS.com, which asks for the resident’s name, address and an email address. The final step in validating residents involves answering four so-called “knowledge-based authentication” or KBA questions. KrebsOnSecurity has relentlessly assailed KBA as an unreliable authentication method because so many answers to the multiple-guess questions are available on sites like Spokeo and Zillow, or via social networking profiles.
Once signed up, a resident can view scanned images of the front of each piece of incoming mail in advance of its arrival. Unfortunately, because of the weak KBA questions (provided by recently-breached big-three credit bureau Equifax, no less) stalkers, jilted ex-partners, and private investigators also can see who you’re communicating with via the Postal mail.
Perhaps this wouldn’t be such a big deal if the USPS notified residents by snail mail when someone signs up for the service at their address, but it doesn’t.
Peter Swire, a privacy and security expert at Georgia Tech and a senior counsel at the law firm of Alston & Bird, said strong authentication relies on information collected from multiple channels — such as something you know (a password) and something you have (a mobile phone). In this case, however, the USPS has opted not to leverage a channel that it uniquely controls, namely the U.S. Mail system.
“The whole service is based on a channel they control, and they should use that channel to verify people,” Swire said. “That increases user trust that it’s a good service. Multi-channel authentication is becoming the industry norm, and the U.S. Postal Service should catch up to that.” Continue reading