KIEV, July 5 (Reuters) - A Ukrainian software firm at the centre of a cyber attack that spread around the world last week said on Wednesday that computers which use its accounting software are compromised by a so-called "backdoor" installed by hackers during the attack.
The backdoor has been installed in every computer that wasn't offline during the cyber attack, said Olesya Bilousova, the chief executive of Intellect Service, which developed M.E.Doc, Ukraine's most popular accounting software.
M.E.Doc is installed in around 1 million computers in Ukraine, she added.
"... the fact is that this backdoor needs to be closed. There was a hacking of servers," Bilousova told reporters. (Reporting by Jack Stubbs; writing by Matthias Williams; Editing by Toby Chopra)