The email accounts of eight foreign journalists working in China and Taiwan were hacked recently, leading Yahoo to suspend several of the accounts last week, the Foreign Correspondent's Club of China (FCCC) said Wednesday.
"We have confirmed eight cases in which journalists in China and Taiwan have had their e-mail accounts hacked in recent weeks, with several accounts disabled by Yahoo on March 25," the FCCC said in an e-mail sent to members.
Among the hacked email accounts, the settings of one account were also modified to forward all emails to another email address, it said.
"Yahoo has not answered the FCCC's questions about the attacks, nor has it told individual mail users how the accounts were accessed. Password security and malware are ongoing concerns, but it's unclear whether they are related to this case," the group said.
The FCCC warned members to change their email passwords and advised them to use other means of communication for arranging interviews or other "sensitive business".
Yahoo was not immediately available to comment.
While there is no evidence linking the hacked email accounts and the Chinese government, the FCCC warning highlights growing concern over the email surveillance of individuals generally viewed with suspicion by the Chinese government, including human rights activists and foreign journalists working in China.
Earlier this month, foreign journalists in China were the target of a sophisticated email malware attack. Emails in that attack appeared to originate from the Shanghai World Expo press office and contained a malicious PDF attachment. The attack seemed to target foreign journalists registered to cover the Expo, which opens on May 1.
In addition, a sophisticated attack from China that targeted the Gmail accounts of Chinese human rights activists in December led Google to close down a censored version of its search engine in China, redirecting users to an uncensored site in Hong Kong instead.
Circumstantial evidence also implicated China in a computer spying network, dubbed GhostNet, that touched users in 103 countries and was used to transfer data to servers in China. The network was discovered in 2009 after researchers were asked to examine computers in offices of the Dalai Lama in India, the US and the U.K. The computers that comprised GhostNet are believed to have been infected by malware in e-mail attachments sent to specific individuals.
The Dalai Lama is viewed with deep suspicion by the Chinese government, which accuses him of working for Tibetan independence.