Posts

Remote LIVE Memory Analysis with The Memory Process File System v2.0

Image
This blog entry aims to give an introduction to The Memory Process File System and show how easy it is to do high-performant memory analysis even from live remote systems over the network. This and much more is presented in my BlueHatIL 2019 talk on February 6th. Connect to a remote system over the network over a kerberos secured connection. Acquire only the live memory you require to do your analysis/forensics - even over medium latency/bandwidth connections. An easy to understand file system user interface combined with continuous background refreshes, made possible by the multi-threaded analysis core, provides an interesting new different way of performing incident response by live memory analysis. The image above shows the user staring MemProcFS.exe with a connection to the remote computer book-test.ad.frizk.net and with the DumpIt live memory acquisition method. it is then possible to analyze live memory simply by clicking around in the file system. Dumping the physical memory ...
Post a Comment
Read more

Total Meltdown?

Image
Did you think Meltdown was bad? Unprivileged applications being able to read kernel memory at speeds possibly as high as megabytes per second was not a good thing. Meet the Windows 7 Meltdown patch from January. It stopped Meltdown but opened up a vulnerability way worse ... It allowed any process to read the complete memory contents at gigabytes per second, oh - it was possible to write to arbitrary memory as well. No fancy exploits were needed. Windows 7 already did the hard work of mapping in the required memory into every running process. Exploitation was just a matter of read and write to already mapped in-process virtual memory. No fancy APIs or syscalls required - just standard read and write! Accessing memory at over 4GB/s, dumping to disk is slower due to disk transfer speeds. How is this possible? In short - the User/Supervisor permission bit was set to User in the PML4 self-referencing entry. This made the page tables available to user mode code in every process. The page t...
Post a Comment
Read more

Introducing the Memory Process File System for PCILeech

Image
The Memory Process File System for PCILeech is an easy and convenient way to quickly look into memory dumps. The processes in a memory dump and their virtual memory should be mapped as files and folders in less than a second. Click around the processes, look at their memory maps and corresponding virtual memory! Oh - if you run it in live mode with a supported PCILeech FPGA device you'll be able to write to memory as well! Super convenient if your target system employs software based anti-forensic or anti-cheating functionality since this is all handled in hardware on the target! Using the Memory Process File System for PCILeech to explore Windows processes in a memory dump file. Cool! So how do I try it out? Check out and download  PCILeech on Github . PCILeech is open source and totally free of charge! You'll find both source code and pre-compiled binaries on Github. How does it work? It works by parsing in-memory page tables which are used by the CPU to translate the virtual...
Post a Comment
Read more

Attacking UEFI

Image
Unlike macs  many PCs are likely to be vulnerable to pre-boot Direct Memory Access (DMA) attacks against UEFI. If an attack is successful on a system configured with secure boot - then the chain of trust is broken and secure boot becomes insecure boot. If code execution is gained before the operating system is started further compromise of the not yet loaded operating system may be possible. As an example it may be possible to compromise a Windows 10 system running Virtualization Based Security (VBS) with Device Guard. This have already been researched by Dmytro Oleksiuk . This post will focus on attacking UEFI over DMA and not potential further compromises of the system. What is UEFI? UEFI is short for Unified Extensible Firmware Interface . It is the firmware that is running on the computer before the operating system is booted. UEFI is responsible for detecting memory, disks and other hardware required to boot the operating system. UEFI is a small operating system in itself. It'...
Post a Comment
Read more

Attacking UEFI Runtime Services and Linux

Image
Attackers with physical access are able to attack the firmware on many fully patched computers with DMA - Direct Memory Access. Once code execution is gained in UEFI/EFI Runtime Services it is possible to use this foothold to take control of a running Linux system. The Linux 4.8 kernel fully randomizes the physical memory location of the kernel. There is a high likelyhood that the kernel will be randomized above 4GB on computers with sufficient memory. This means that DMA attack hardware only capable of 32-bit addressing (4GB), such as PCILeech , cannot reach the Linux kernel directly. Since the EFI Runtime Services are usually located below 4GB they offer a way into Linux on high memory EFI booting systems. Please see the video below for an example of how an attack may look like. What are the EFI Runtime Services? UEFI on PCs, EFI on macs, is the modern day BIOS. UEFI is short for Unified Extensible Firmware Interface. UEFI is responsible for detecting hardware and configuring device...
Post a Comment
Read more

macOS FileVault2 Password Retrieval

Image
macOS FileVault2 let attackers with physical access retrieve the password in clear text by plugging in a $300 Thunderbolt device into a locked or sleeping mac. The password may be used to unlock the mac to access everything on it. To secure your mac just update it with the December 2016 patches. Anyone including, but not limited to, your colleagues, the police, the evil maid and the thief will have full access to your data as long as they can gain physical access - unless the mac is completely shut down. If the mac is sleeping it is still vulnerable. Just stroll up to a locked mac, plug in the Thunderbolt device, force a reboot (ctrl+cmd+power) and wait for the password to be displayed in less than 30 seconds! Check out the demo video below: How is this possible? At the very core of this issue there are two separate issues. The first issue is that the mac does not protect itself against Direct Memory Access (DMA) attacks before macOS is started. EFI which is running at this early stage...
Post a Comment
Read more

Windows 10 KASLR Recovery with TSX

Image
It is possible to break Kernel Address Space Layout Randomization (KASLR) on modern operating systems running on modern x86 CPU's. One possible way of doing this is to time certain operations when using the Transactional Synchronization Extensions (TSX) instruction set. TSX makes it possible for unprivileged user mode programs to detect whether certain virtual memory pages are mapped or unmapped in kernel mode. It is also possible to detect whether a kernel page is executable or not. It has been known since at least 2014 that timing attacks against KASLR, using TSX, is possible. This was discussed by Rafal Wojtczuk from Bromium Labs in the blog post TSX improves timing attacks against KASLR . The technique was popularized and presented at Black Hat US-16 by Yeongjin, Sangho, and Taesoo from Georgia Institute of Technology. Their presentation and white paper is found on the Black Hat site. Example code for Linux was published on Github after the talk. Since no example code was pub...
Post a Comment
Read more