U.S. energy firms have recently faced escalated cyberattacks from Iran-backed hackers, U.S. officials have reported. According to the Wall Street Journal, "In the latest operations, the Iranian hackers were able to gain access to control-system software that could allow them to manipulate oil or gas pipelines."

Via the WSJ:

U.S. officials consider this set of Iranian infiltrations to be more alarming than another continuing campaign, also believed to be backed by Tehran, that disrupts bank websites by “denial of service” strikes. Unlike those, the more recent campaigns actually have broken into computer systems to gain information on the controls running company operations and, through reconnaissance, acquired the means to disrupt or destroy them in the future, the U.S. officials said.

In response, U.S. officials warn that Iran is edging closer to provoking U.S. retaliation.

“This is representative of stepped-up cyber activity by the Iranian regime. The more they do this, the more our concerns grow,” a U.S. official said. “What they have done so far has certainly been noticed, and they should be cautious.”

The U.S. has previously launched its own cyberattacks against Iran. The Stuxnet worm, developed and launched by the U.S. and Israel, sabotaged an Iranian nuclear facility.