The leaked files from surveillance software maker Hacking Team have proven to be a great resource for cyberespionage groups, which have used at least two Flash Player exploits from the company's arsenal.
Last Tuesday, security researchers from security firm FireEye detected targeted attacks against organizations in Japan, with the attackers using an exploit for CVE-2015-5122, a Flash Player vulnerability patched by Adobe Systems that same day.
The vulnerability was publicly known before that date because an exploit for it was found in the 400GB data cache recently leaked by a hacker from Milan-based Hacking Team.
An unknown hacker broke into the computer network of Hacking Team, a company that sells computer surveillance software and intrusion tools to government agencies worldwide. The attacker released email communications, client lists, files, source code, documentation and previously unknown software exploits.
The group of attackers that targeted the Japanese organizations did so through strategic Web compromises, also known as watering hole attacks. The tactic involves compromising websites that are typically visited by organizations from particular industries.
Two websites compromised in this case belonged to Japan's International Hospitality and Conference Service Association (IHCSA) and Cosmetech, a Japanese cosmetics company.
Once victims visited those websites, malicious scripts loaded the Flash Player exploit. While the FireEye researchers haven't determined with certainty yet how the victims were lured to the compromised websites, phishing emails are a strong candidate. Otherwise, victims were unlikely to land there simply by chance.
It's not clear what group is responsible for the attack, but the malware program installed by the exploit is almost exclusively used by Chinese hacker groups, the FireEye researchers said in a blog post Sunday.
"The Japanese economy's technological innovation and strengths in high-tech and precision goods have attracted the interest of multiple Chinese [advanced persistent threat] groups, who almost certainly view Japanese companies as a rich source of intellectual property and competitive intelligence," they said.
These attacks come after other cyberespionage groups used another Flash Player exploit found among the Hacking Team files that was patched two weeks ago. Those attacks also targeted U.S. government agencies, prompting the FBI to issue an alert.