When hacktivist collective Anonymous declared Dec. 11 as the “ISIS Day of Trolling,” fundamentalists fought back by releasing the personal information of 160 unsuspecting U.S. military personnel.

Anonymous declared a cyberwar against ISIS shortly after the Nov. 13 Paris attacks. Though the group has effectively uncovered important data while fighting its digital adversaries in the past, ISIS is a completely different animal. The group thrives on digital warfare and propaganda, so when Anonymous encouraged the entire world to tweet offensive imagery to ISIS accounts, it retaliated in a dangerous way.

Social media accounts connected to the Islamic Cyber Army, the terrorist organization’s digital arm, tweeted the names, addresses and phone numbers of U.S. Marines and soldiers. It also bragged that it had the data of 700 more military personnel.

Doxxing, or the unlawful release of a person’s personal information via social media, is dangerous because it helps violent individuals track down and harass victims. Publishing information as personal as a person’s cellphone number or home address sends a message that online abusers can find and hurt you anywhere.

The practice is harmful for military veterans because it leads ISIS sympathizers straight to the front doors of people they view as enemies. An ISIS supporter was recently indicted for doxxing 100 military members on his Tumblr account. A jihadist’s widow also doxxed former SEAL Robert O’Neil, the man who shot Osama Bin Laden, and  Sgt. Dillard Johnson, a veteran who bragged about killing terrorists in his book.

Thankfully, ISIS isn’t as powerful or omnipresent as its leaders would like you to believe. A lot of the information it is publishing is publicly available, which means that fundamentalists don’t have access to restricted data. The biggest threat posed by this round of doxxing is that ISIS is publicizing the information to a radicalized audience.

From the Christian Science Monitor:

“We can’t confirm that there was any hacking,” said Rita Katz, director of SITE, even suggesting that some of the information could be fabricated. “It seems that the group is taking lists from military websites, collecting information from Google, and possibly even releasing bogus information.”

…

Katz says the group has not yet released any information that can’t be found through public sources such as Google searches.

Still, she said, “since some of the lists released by the pro-IS group are copied from US military sites, it’s troubling that people affiliated with IS are seeing lists affiliated with the military, regardless of whether it is publicly available or not.”