Two NHS websites have been hacked and defaced by Haxor Hussy (H4x0r HuSsY), a member of the Pakistan based Madleets group.
The affected websites were both small subdomains for hospital library services in the south west of England.
One site is designed to enable book lending between south west, Wessex and Thames Valley hospitals. The other is for users to get information about health education books available in libraries across the south west region.
"Struck by H4x0r HuSsY. Security breached by Madleets," the hacker wrote on the websites. Both have now been restored.
The websites are built using WordPress and it appears that the hacker exploited a vulnerability in Wordpress in order to breach them, The Hackers Post reports.
Despite the seemingly random attacks, on the Madleets Facebook page, the group describes itself as an "ethical and 1337 [elite] White Hat Hackers Community," adding "we are Anti Hackers , we teach how to protect yourself from getting hacked".
Recently, Haxor Hussy has also hacked the Indian BioResource Information Network and a number of Indian government websites ran by the state of Goa.
In August Madleets members, including Haxor Hussy, hacked and defaced a prominent pro-Israeli online forum.
Last year, the website of South London Healthcare NHS Trust was breached, with its content replaced with a message written in Arabic.