Zoom has become a target for harassment and abuse coordinated in private off-platform chats.

By Taylor Lorenz and Davey Alba

In recent weeks, as schools, businesses, support groups and millions of individuals have adopted Zoom as a meeting platform in an increasingly remote world, reports of “Zoombombing” or “Zoom raiding” by uninvited participants have become frequent.

While those incidents may have initially been regarded as pranks or trolling, they have since risen to the level of hate speech and harassment, and even commanded the attention of the F.B.I.

The weaponization of Zoom — a videoconferencing app that has become a de facto social platform for the coronavirus era — is the latest development in the story of online abuse, the kind playing out on social networks and darker, unmoderated corners of the internet.

An analysis by The New York Times found 153 Instagram accounts, dozens of Twitter accounts and private chats, and several active message boards on Reddit and 4Chan where thousands of people had gathered to organize Zoom harassment campaigns, sharing meeting passwords and plans for sowing chaos in public and private meetings.

Zoom raiders often employ shocking imagery, racial epithets and profanity to derail video conferences. Though a meeting organizer can remove a participant at any time, the perpetrators of these attacks can be hard to identify; there may be several in a single call, and they can appear to jump from one alias to another.

On March 29, Zahed Amanullah was in the middle of a call he had organized with the Concordia Forum, a global network of Muslim leaders, about maintaining spirituality and wellness during the coronavirus crisis, when suddenly a cursor began to draw a racial slur across one of the slides.

“What is that? How did that happen?” one of the meeting’s presenters said as it was appearing. “Did somebody just see what I saw?”

The infiltrator then began to screen-share a pornographic video while repeating the racial epithet verbally.

“We were all caught off guard,” said Mr. Amanullah, a resident senior fellow at the Institute for Strategic Dialogue in London. “We had no clue where it was coming from.”

Harassers have begun to leverage every feature of Zoom’s platform for abuse. They have used the app’s custom background feature to project a GIF of a person drinking to participants in an Alcoholics Anonymous meeting, and its annotation feature to write racist messages in a meeting of the American Jewish Committee in Paris.

“When you see this kind of rampant abuse, it isn’t just a one-off thing,” said Whitney Phillips, an assistant professor at Syracuse University who teaches digital ethics. “Clearly, this is systemic.”

Zoom has exploded in popularity as the global population has become increasingly homebound in an effort to limit the spread of coronavirus. According to the app data firm SensorTower, first-time installs of the videoconferencing company’s mobile app rose by 1,126 percent in March to more than 76 million, up from just 6.2 million in February.

But the company was not prepared for the rapid growth of its user base. Zoom has offered guidance on making conferences more secure by changing call settings and offering tutorials, but many users have been unsatisfied with the company’s response to specific incidents of harassment.

“Zoom’s response was like, ‘We’re sorry,’ as if this only happened to me,” said Dennis Johnson, a doctoral candidate who complained to Zoom after his dissertation defense was disrupted by pornography and a racial slur. “They treated me like an isolated incident — that’s my biggest issue.”

The company gave an email statement on Thursday. “Zoom strongly condemns harassment of this kind and we have been reporting instances of this to various social platforms in order for them to take appropriate action,” said Nate Johnson, a Zoom spokesman.Sign up to receive our daily Coronavirus Briefing, an informed guide with the latest developments and expert advice.Sign Up

The frequency and reach of the incidents on Zoom prompted the F.B.I. to issue a warning on Tuesday, singling out the app and stating that it had “received multiple reports of conferences being disrupted by pornographic or hate images and threatening language” nationwide.

On dozens of Twitter accounts and online forums, people are drawn into private group chats on Discord, an app that has been popular in far-right circles. There, people share Zoom codes, raid video conferences simultaneously and designate point values for certain types of harassment in order to drive competition. The Times discovered 14 active Discord chats with dozens of messages sent a minute, with the most popular chat hosting over 2,000 people.

“This behavior violates Discord’s terms of service, and we strongly condemn it,” a spokesperson from Discord said in an email statement. “Once we identify those servers engaging in this sort of activity, we quickly investigate and take action, including removing content, banning users and shutting down those servers.”

On Instagram, a network of accounts with names like “Zoomraid” and “Zoomattack” began to appear over the weekend and saw a spike in followers — nearly 30,000 as of Thursday. The owners of these accounts post Zoom meeting codes so that others can coordinate raids of password-protected videoconferences.

“We don’t want Instagram used this way. We will block hashtags used to coordinate zoombombing and remove accounts created solely for the purpose of zoombombing when we see them,” a Facebook company spokesperson said via email.

As classrooms across the country have largely shifted to online-only education in the wake of the coronavirus pandemic, many students feel ill equipped to perform in this new learning environment. Several teenagers who ran Zoom raid accounts spoke about their frustrations with online schooling and how, for them, Zoom raiding classes provided an outlet. It was the only way they felt they could escape their crushing academic workload.

Most of the accounts run by teenagers are operating with the goal of derailing middle and high school classes with disruptive but largely inoffensive jokes.

“Part of the reason we do it is a lot of teachers give us a lot of work right now,” said James, 16, who runs a Zoom raid account. “It’s stressing us out. We just got home for quarantine and on top of all that we have all this schoolwork to do. We still have tests to do, I have more work to do sometimes now than before because every teacher will assign stuff every week and sometimes classes get in the way of each other. It’s really stressful to keep up.”

Some Instagram meme accounts, which typically share funny videos from TikTok, have also begun posting Zoom meeting information in order to boost engagement.

“We go on our Story and post the info for the Zoom class,” said Aaliyah, 17, an administrator for several Instagram meme accounts. “We say, if you join, do something funny we will follow you back.”

But for each frustrated teenager trying to escape class, there are many others with bad intentions.

The more nefarious organizing tends to happen on Discord. In one Discord chat, a middle school’s class schedule, including Zoom links for each class, was shared with hundreds of members who stated their intent to harass the students and their teachers.

Another group discussed disrupting a singles mixer organized by a Baptist church in Virginia. “As soon as it starts there’s gonna be rape,” one member said. “I’m putting gore on straight away,” another added.

Alcoholics Anonymous, which has largely transitioned to open online meetings using Zoom, has become a frequent target. “Have fun with these AA codes,” one Discord user wrote in a post that linked to nearly 600 A.A. meetings in California. Another uploaded a 28-page document with links to support groups for trans and nonbinary youth.

Jeff, a 39-year-old A.A. member in Los Angeles, said that in the last three weeks he has attended 30 meetings using Zoom. Every single one, he said, had been interrupted by an online troll.

When he enters a virtual A.A. meeting now, Jeff said, his heart starts racing. “It’s a sense of fear and panic, but also a sadness around the loss of this place to be vulnerable,” he said.

Videos and live streams of Zoom harassment have begun to appear on YouTube and Twitch, the Amazon-owned video-gaming site. A popular YouTuber streamed himself for over six hours harassing dozens of A.A. meetings hosted on Zoom. Another video posted March 30 about crashing college classes racked up more than 4.2 million views and inspired a slew of copycats. One video posted by a YouTuber with 1.7 million subscribers that purported to show “raids of online classes” instead displayed a woman facing harassment in an A.A. meeting.

“We have strict policies that prohibit content containing harassment, hate speech, or unwanted sexualization and we quickly remove content when flagged by our users,” said Alex Joseph, a YouTube spokesman.

Ms. Phillips, of Syracuse University, said that without more aggressive moderation, Zoom risks normalizing such behavior on its platform. “Developers of platforms either don’t take the risks of abuse seriously or don’t anticipate those risks, which amounts to the same problem,” she said.

Mr. Amanullah said he was disappointed that his meeting was turned into a platform for hate speech. He said that the group promoted it on social media to draw a wider audience.

“Certain people are weaponizing Zoom to sow division in society or spread hate,” Mr. Amanullah said. “Those of us who are of particular backgrounds and who are targets of hate bear the brunt of it.”

Adam Satariano and Ben Decker contributed reporting.