According to Kaspersky Lab, the vulnerability has being exploited by the BlackOasis threat actor. The recent attacks leveraging today's zero-day sent malicious Office documents to victims, which came with an embedded ActiveX object that contained the Flash CVE-2017-11292 exploit.
The weakness was reported to Microsoft by researchers at China-based security firm Qihoo 360. The experts said they first observed an attack exploiting this vulnerability on September 28. The attacks targeted a small number of the company’s customers and they involved malicious RTF files.
The vulnerability was detected by FireEye researchers. The attacker used Microsoft Office RTF document to leverage RCE in .NET Framework and deploy FINSPY malware. The malicious document “Проект.doc” (MD5: fe5c4d6bb78e170abf5cf3741868ea4c) had Russian name and might have been used to target a Russian speaker.
A backdoor code was detected in NetSarang software on August 4, 2017. Next day, on August 5 the developer has released an update to resolve the issue. As of August 15, there is an evidence, that the code has being utilized by one instance in Hong Kong.
The malicious code was delivered to the vendor's clients by compromising the software update mechanism. The backdoor was included into updates, issued on July 18, 2017. The update contained ShadowPad backdoor.
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