RTF Design, Office Flaw Exploited in Multi-Stage Document Attack

A newly discovered multi-stage document attack exploits design behaviors in .docx and RTF, along with CVE-2017-8570, to drop a malicious payload called Formbook on target endpoints. Attackers bypass traditional security tools with embedded URLs instead of active code.

Researchers at Menlo Security Labs who isolated the second-stage document say the behaviors enabling this attack are not new, but that this threat demonstrates an increasingly common way for hackers to slip past security defenses by relying on remotely hosted malicious objects.

“What we discovered is a new way in which Windows is getting the second-stage payload,” says Vinay Pidathala, Menlo’s director of security research. “There’s absolutely no macros, no shellcode being used, just a URL. When the victim opens the document, it will go and fetch the remotely hosted components and load it in the context of the Word process.”

Read more about this newly discovered attack on DarkReading.

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