Bypassing windows firewall with AMT

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Pigeon
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Bypassing windows firewall with AMT

Post by Pigeon » Fri Jun 09, 2017 1:07 am

The group, which Microsoft has named PLATINUM, has developed a system for sending files—such as new payloads to run and new versions of their malware—to compromised machines. PLATINUM's technique leverages Intel's Active Management Technology (AMT) to do an end-run around the built-in Windows firewall. The AMT firmware runs at a low level, below the operating system, and it has access to not just the processor, but also the network interface.

The AMT needs this low-level access for some of the legitimate things it's used for. It can, for example, power cycle systems, and it can serve as an IP-based KVM (keyboard/video/mouse) solution, enabling a remote user to send mouse and keyboard input to a machine and see what's on its display. This, in turn, can be used for tasks such as remotely installing operating systems on bare machines. To do this, AMT not only needs to access the network interface, it also needs to simulate hardware, such as the mouse and keyboard, to provide input to the operating system.

But this low-level operation is what makes AMT attractive for hackers: the network traffic that AMT uses is handled entirely within AMT itself. That traffic never gets passed up to the operating system's own IP stack and, as such, is invisible to the operating system's own firewall or other network monitoring software. The PLATINUM software uses another piece of virtual hardware—an AMT-provided virtual serial port—to provide a link between the network itself and the malware application running on the infected PC.

Communication between machines uses serial-over-LAN traffic which is handled by AMT in firmware. The malware connects to the virtual AMT serial port to send and receive data. Meanwhile, the operating system and its firewall are none the wiser. In this way, PLATINUM's malware can move files between machines on the network while being largely undetectable to those machines.

https://arstechnica.com/security/2017/0 ... -firewall/

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