Attackers are using fake versions of a recently released report about a Chinese cyberespionage group as bait in new spear-phishing attacks that target Japanese and Chinese users.The report was released Tuesday by security firm Mandiant and documents in great detail the cyberespionage campaigns conducted since 2006 by a hacker group known as the Comment Crew against more than 100 companies and organizations from different industries.Mandiant refers to the group as APT1 (Advanced Persistent Threat 1) and claims in the report that it's likely a secret Shanghai-based cyberespionage unit of the Chinese Army -- the People's Liberation Army (PLA) -- code-named "Unit 61398."The Chinese government has dismissed Mandiant's claims as groundless. However, the report received a lot of attention from people in the IT security industry, as well as from the general public.It seems that this publicity has now led to attackers deciding to use the report as bait in new targeted attacks.Two different spear-phishing attacks were discovered on Thursday using emails with malicious attachments that masqueraded as the Mandiant report, said Aviv Raff, the chief technology officer of security firm Seculert.One attack targeted Japanese-speaking users and involved emails with an attachment called Mandiant.pdf. This PDF file exploits a vulnerability in Adobe Reader that was patched by Adobe in an emergency update Wednesday, security researchers from Seculert said in a blog post.The malware installed by the exploit connects to a command-and-control server hosted in Korea, but also contacts some Japanese websites, probably in an attempt to trick security products, the Seculert researchers said.Symantec has also detected and analyzed the spear-phishing attack. "The email purports to be from someone in the media recommending the report," Symantec researcher Joji Hamada said in a blog post. However, it would be evident for a Japanese person that the email was not written by a native Japanese speaker, he said.Hamada pointed out that similar tactics have been used in the past. In one incident back in 2011, hackers used a research paper about targeted attacks published by Symantec as bait. "They did this by spamming targets with the actual whitepaper along with malware hidden in an archive attachment," Hamada said.The second spear-phishing attack detected on Thursday targets Chinese-speaking users and uses a malicious attachment called "Mandiant_APT2_Report.pdf."According to an analysis of the PDF file by researcher Brandon Dixon of security consultancy firm 9b+, the document exploits an older Adobe Reader vulnerability that was discovered and patched in 2011.The malware installed on the system establishes a connection to a domain that currently points to a server in China, Dixon said via email. "The malware provides attackers with the ability to execute commands on the victim's system."The domain name contacted by this malware was also used in the past in attacks that targeted Tibetan activists, Seculert's Raff said. Those older attacks installed both Windows and Mac OS X malware, he said.Greg Walton, a researcher from MalwareLab, a security outfit that tracks politically motivated malware attacks, said on Twitter that the Mandiant-themed spear-phishing attack targeted journalists in China. This information could not be confirmed by Raff or Dixon, who said that they don't have copies of the original spam emails, only of the malicious attachment they contained.