Mr. Ahlberg said his company, which pulls intelligence from open and closed web forums, ISIS propaganda forums, social media and an array of other information tools, has yet to see any public pronouncement from the Islamic State that would indicate it has acquired hacking capabilities.

Hacking attacks are barely mentioned in Dabiq, the Islamic State’s online magazine, and other instructional documents, according to an analysis by Recorded Future. The words “cyber,” “cyber attack” and “hacking” do not appear in any of the 740 recent ISIS propaganda and instructional materials that Mr. Ahlberg’s company looked at. Nor do any ISIS materials focus on such attacks as a core ambition.

Of the two Islamic State sympathizers believed to have the most sophisticated hacking skills, one, Ardit Ferizi, a 20-year-old citizen of Kosovo, has been imprisoned in Malaysia. He is awaiting extradition to the United States where he faces up to 35 years in prison, according to a Justice Department indictment.

The other, Junaid Hussain, a 21-year-old British-born Pakistani who is credited with breaking into the United States Central Command’s Twitter and YouTube accounts in January, was killed in a drone strike in Syria in August.

Still, officials worry that even with their ranks of talented hackers depleted, the Islamic State could one day recruit more sophisticated hackers. The group has already shown itself to be adept at using social media to draw in new members, said Rita Katz, the executive director and co-founder of the SITE Intelligence Group, which monitors ISIS’s online activity.

Online discussions among ISIS members used to take place almost exclusively in password-protected forums, Ms. Katz said. But Twitter, YouTube and Tumblr offer a far bigger audience, as well as a means of communicating with other fighters and prospective recruits.

It was on Twitter that Mr. Hussain and Mr. Ferizi, both well-known hackers, re-emerged as ISIS fighters. On Twitter, Mr. Hussain publicly instigated online attacks, posted information on American military forces and officers, and cheered on other fighters in the group, according to Ms. Katz.