AT&T Inc. (NYSE:T) is exploring a sale of its cybersecurity division, potentially undoing an acquisition it completed five years ago, according to people familiar with the matter. The sale of the cybersecurity business would add to a string of divestments AT&T has turned to in order to pay down debt following its $108.7 billion acquisition of Time Warner Inc. in 2018, a deal it has since also unwound. In the last two years, AT&T sold a 30% stake in its pay TV unit DirecTV to private equity firm TPG for $1.8 billion, and received $40.4 billion in cash by spinning off and merging its Warner Media business with Discovery Communications to form Warner Bros Discovery Inc. (WBD.O).

AT&T has been working with Barclays Plc (BARC.L) to solicit potential bids for its cybersecurity business, which was called Alienvault when it was acquired in 2018 in a roughly $600 million deal, the sources said. It is not clear how much the business could fetch now. The sources cautioned that no deal is certain and requested anonymity because the matter is confidential.

AT&T and Barclays declined to comment.