How watermarks from your printer or copier could be spilling your secrets

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Hidden watermarks, or tracking dots, are not unique to classified documents; they could be on every page you print at home or work. (Source: 3TV/CBS 5) Hidden watermarks, or tracking dots, are not unique to classified documents; they could be on every page you print at home or work. (Source: 3TV/CBS 5)

Many security researchers believe hidden watermarks on a classified report helped the FBI track down and arrest the government contractor accused of leaking it.

These hidden watermarks, or tracking dots, are not unique to classified documents; they could be on every page you print at home or work.

Reality Leigh Winner is accused of printing out a top secret report detailing election-related Russian hacking efforts and mailing the document to a news agency. The document was published by The Intercept.

Several security researchers have pointed out the classified report posted by The Intercept has visible watermarks – yellow dots -- that contain tracking information identifying the date and time the document was printed, along with the exact printer model.

This post identifies exactly how to spot and analyze the watermarks: click here. Court documents filed in Winner's case do not explicitly say the FBI used this method and federal investigators have declined to comment on it.

Many color laser printers and copiers add watermarks to every printed page, said Ken Colburn of Data Doctors, but the exact number of printers and copiers that do so is unclear. The Electronic Frontier Foundation has a partial list.

Companies started introducing watermarks in the 90s as a way to help prosecutors track counterfeiters, Colburn said.

“It's generally the color printers that are higher level, laser, because they're capable of creating very hard to distinguish counterfeit money,” he said.

Colburn said graphics programs that can zoom in on a printed image make it easy to spot the watermarks. He demonstrated that it’s also possible to spot the yellow dots using a magnifying glass and a blue light. Blue light makes the yellow marks appear darker.

Modern copy machines have a separate security concern – one that Colburn considers even more serious than the watermarks.

“If you have a copier that's made in the last 10 or 15 years, there's a very high likelihood that is has a hard drive on it,” he said.

The hard drive stores every image that’s been scanned. That means copiers can be loaded with secrets. In 2010, CBS 5 reviewed four copier hard drives and found sensitive payroll data from a Scottsdale restaurant: everything from names and social security numbers to copies of traveler’s checks.

“If you don't take the time to wipe that drive you're potentially handing somebody a lot of information about you or your organization you probably wouldn't want in those hands,” Colburn said.

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Derek StaahlDerek Staahl is an Emmy Award-winning reporter and fill-in anchor who loves covering stories that matter most to Arizona families.

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Derek Staahl

This once-uncompromising "California guy" got his first taste of Arizona in 2015 while covering spring training baseball for his former station. The trip spanned just three days, but Derek quickly decided Phoenix should be his next address. He joined CBS 5 and 3TV four months later, in August 2015. Before packing his bags for the Valley of the Sun, Derek spent nearly four years at XETV in San Diego, where he was promoted to Weekend Anchor and Investigative Reporter. Derek chaired the Saturday and Sunday 10 p.m. newscasts, which regularly earned the station's highest ratings for a news program each week. Derek’s investigative reporting efforts into the Mayor Bob Filner scandal in 2013 sparked a "governance crisis" for the city of San Diego and was profiled by the region’s top newspaper. Derek broke into the news business at WKOW-TV in Madison, WI. He wrote, shot, edited, and presented stories during the week, and produced newscasts on the weekends. By the end of his stint, he was promoted to part-time anchor on WKOW’s sister station, WMSN. Derek was born in Los Angeles and was named the “Undergraduate Broadcast Journalism Student of the Year” in his graduating class at USC. He also played quads in the school’s famous drumline. When not reporting the news, Derek enjoys playing drumset, sand volleyball, and baseball.

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