Law firms' largely internal usage of Microsoft Teams, Slack and other messaging apps hasn't notably increased their cybersecurity risk, observers said. But cybersecurity and IT tech providers warn that allowing firmwide and external access to these platforms could unleash significant exposure and damage.

To be sure, messaging apps can lead to data security incidents, according to the "Data Loss Prevention Report" released in 2021 from email cybersecurity tech company Egress. Of the 500 IT leaders and 3,000 remote financial services, legal or health care sector employees surveyed, 77% said message apps, including Teams and SMS, were a "source of incidents."