HOUSTON, Aug 21 (Reuters) - Top US oilfield services

firm Halliburton ( HAL ) on Wednesday was hit by a cyberattack,

according to a person familiar with the matter.

The attack appeared to impact business operations at the

company's north Houston campus, as well as some global

connectivity networks, the person said, who declined to be

identified because they were not authorized to speak on the

record.

Spokespeople for the company did not immediately respond to

requests for comment. The company has asked some staff not to

connect to internal networks, the person said.

Cyberattacks have been a major headache for the energy

industry. In 2021, hackers attacked the Colonial Pipeline with

ransomware, causing a days-long shutdown to the major fuel

supply line.

That breach, which the FBI attributed to a gang called

DarkSide, led to a spike in gasoline prices, panic buying and

localized fuel shortages. It also created a major political

headache for President Joe Biden as the U.S. economy was

starting to emerge from the COVID-19 pandemic.

Several major U.S. companies have suffered ransomware

attacks in recent years, including UnitedHealth Group ( UNH ),

gambling giants MGM Resorts International ( MGM ), Caesars

Entertainment CZR.O and consumer good maker Clorox.

(Reporting by Liz Hampton in Denver and Chris Sanders in

Washington)