Have you shared your old senior photo on Facebook? Hackers may be using your post against you.

A seemingly innocent new Facebook trend has been increasingly popping up on news feeds — people sharing their old high school senior photos in support of the class of 2020. But those nostalgic posts could make users more susceptible to hackers trying to break into their online accounts, among other security issues. 

"In support of this year's seniors, class of 2020, share YOUR senior picture no matter how old you are," instructs one iteration of the post circulating on Facebook. Users also typically share the name of their high school and graduation year, often with the hashtag #classof2020. 

The sweet idea, meant to show solidarity with this year's seniors who may miss out on their proms and graduations due to the coronavirus pandemic, may actually help cybercriminals obtain private information that could be used against you.

"The trend encourages you to share revealing personal details — your graduation year and class photo, for example — that can be used to infer other revealing details, like your date of birth and city you grew up in," said Dan Patterson, a senior producer for CNET. "Criminals often use these details to hack social media accounts, guess security questions on financial sites, and send customized 'spear phishing' messages designed to fool you into forking over sensitive information."

The Better Business Bureau (BBB) advised people to think twice before participating in the trend. In a news release Monday, the organization warned that while it may seem like the information is just being shared with your friends, it could also be seen by "scammers or hackers who surf through social media sites." 

The BBB cited similar concerns about other recent "personal list" trends on Facebook, including posting about the make and model years of all the vehicles you've ever owned, your favorite athletes, and your top 10 favorite shows.  

"What most people forget is that some of these "favorite things" are commonly used passwords or security questions," the consumer group warned. 

The organization pointed out that for users whose privacy settings aren't highly restrictive, the valuable information could be up for grabs "for anyone to use."

Patterson explained that it is "highly probable" the information users innocently post in the viral senior photo trend will be used in ways they didn't expect. 

"Your social media data, credit details, and public photos are traded by advertisers, hackers, cybercriminals, marketing agencies and data brokers," noted Patterson, who has advised users to steer clear of viral Facebook trends. "It's highly probable information used in this social media trend will be weaponized or co-opted by bad actors and in the future. Once your data is in the wild, it stays in the wild and can be used by any number of unscrupulous characters."

The BBB also encourages users to "resist the temptation to play along" with the viral trends if they feel uncomfortable participating and review their security settings on all social media platforms "to see what you are sharing and with whom you are sharing." In addition, it encourages users who may be nervous that something they shared on social media could potentially make them more susceptible to fraud, to review and update their security settings for banking sites and other sensitive portals.