LLVM can now emit/parse/diff Windows PDBs

PDBs are the sidecar symbol files for Windows. The spec used to be private, now is public, and now it is great to see Clang supporting them. Last time I looked, GCC does not support them.



Cr4sh’s DmaHvBackdoor.c: Hyper-V backdoor for UEFI

Cr4sh is having fun with Windows Device Guard:

DmaHvBackdoor.c comments:

Part of UEFI DXE driver code that injects Hyper-V VM exit handler backdoor into the Device Guard enabled Windows 10 Enterprise. Execution starts from new_ExitBootServices() — a hook handler for EFI_BOOT_SERVICES.ExitBootServices() which being called by winload!OslFwpKernelSetupPhase1(). After DXE phase exit winload.efi transfers exeution to previously loaded Hyper-V kernel (hvix64.sys) by calling winload!HvlpTransferToHypervisor(). To transfer execution to Hyper-V winload.efi uses a special stub winload!HvlpLowMemoryStub() copied to reserved memory page at constant address 0x2000. During runtime phase this memory page is visible to hypervisor core at the same virtual and physical address and has executable permissions which makes it a perfect place to store our Hyper-V backdoor code. VMExitHandler() is a hook handler for VM exit function of hypervisor core, it might be used for interaction between hypervisor backdoor and guest virtual machines.

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Microsoft Windows DMA Guard

[…] New Bitlocker features in Windows 10, version 1507:
* DMA port protection. You can use the DataProtection/AllowDirectMemoryAccess MDM policy to block DMA ports when the device is starting up. Also, when a device is locked, all unused DMA ports are turned off, but any devices that are already plugged into a DMA port will continue to work. When the device is unlocked, all DMA ports are turned back on.

This policy setting allows you to block direct memory access (DMA) for all hot pluggable PCI downstream ports until a user logs into Windows. Once a user logs in, Windows will enumerate the PCI devices connected to the host plug PCI ports. Every time the user locks the machine, DMA will be blocked on hot plug PCI ports with no children devices until the user logs in again. Devices which were already enumerated when the machine was unlocked will continue to function until unplugged. This policy setting is only enforced when BitLocker or device encryption is enabled.




Intel Graphics Driver for Windows: DoS vulnerability

Excerpt of advisory below, see full one for list of drivers impacted.

DoS in Kernel in multiple versions of the Intel Graphics Driver allows local attacker to perform a DoS via an Out of Bounds Read

Intel ID: INTEL-SA-00077
Product family: Mobile, Desktop, Server, Workstation, and Embedded processors based on Intel® Core™ and Atom™ Processors using an affected driver.
Impact of vulnerability: Denial of Service
Severity rating: Moderate
Original release: Jul 31, 2017
Last revised: Aug 01, 2017

Out-of-bounds read condition in older versions of some Intel® Graphics Driver for Windows code branches allows local users to perform a denial of service attack. Intel recommends that users download and upgrade to the latest supported driver. Intel would like to thank Enrique Nissim of IOActive for reporting this issue and working with us on a coordinated disclosure.



Microsoft launches Windows Bounty Program

Announcing the Windows Bounty Program:
Windows 10 represents the best and newest in our strong commitment to security with world-class mitigations. One of Microsoft’s longstanding strategies toward improving software security involves investing in defensive technologies that make it difficult and costly for attackers to find, exploit and leverage vulnerabilities. We built in mitigations and defenses such as DEP, ASLR, CFG, CIG, ACG, Device Guard, and Credential Guard to harden our systems and we continue adding defenses such as Windows Defender Application Guard to significantly increase protection to harden entry points while ensuring the customer experience is seamless. In the spirit of maintaining a high security bar in Windows, we’re launching the Windows Bounty Program on July 26, 2017. This will include all features of the Windows Insider Preview in addition to focus areas in Hyper-V, Mitigation bypass, Windows Defender Application Guard, and Microsoft Edge. We’re also bumping up the pay-out range for the Hyper-V Bounty Program.[…]




Microsoft Windows Defender ATP

What’s new in Windows Defender ATP Fall Creators Update:
When we introduced Windows Defender Advanced Threat Protection (Windows Defender ATP), our initial focus was to reduce the time it takes companies to detect, investigate, and respond to advanced attacks. The Windows Fall Creators Update represents a new chapter in our product evolution as we offer a set of new prevention capabilities designed to stop attacks as they happen and before they have impact. This means that our service will expand beyond detection, investigation, and response, and will now allow companies to use the full power of the Windows security stack for preventative protection. The stack will be powered by our cloud-based security intelligence, which moves us from a world of isolated defenses to a smart, interconnected, and coordinated defense grid that is more intelligent, simple to manage, and ever-evolving. We will also provide a single pane of glass experience for security professionals. This means that security management (SecMgmt) teams can easily configure a broad set of Windows security stack technologies through an integrated configuration management experience. Security operations (SecOps) teams get full visibility into their Windows endpoint security and a rich toolset to take action using the Windows Defender ATP console. This will not only give companies a full picture of what’s happening on their endpoints, but will also put them in the driver seat to quickly react to threats as they happen. Leveraging our cloud-based security intelligence gives the optics, context, and tools that companies need to quickly investigate and remediate incidents. Here are some highlights of the Windows Fall Creators Update:[…]





Adaptiva Secure 10: BIOS to UEFI

New registration-required freeware from Adaptiva:

Adaptiva’s free Secure 10 is a complete automation solution for ConfigMgr admins to make the BIOS to UEFI conversion process simple and unattended. With Secure 10, migrations take much less time and no IT staff need to be on-site during the process. Now including support for new MBR2GPT.exe tool for retaining data while making the switch, as well as ConfigMgr 1610+ WinPE boot image pre-staging. Also new: two complete task sequences to save time integrating into your deployments! […] The open solution includes detailed documentation to help SCCM system administrators overcome the complexities of automating the conversion from:

* BIOS to UEFI – Secure 10 automates the conversion process from the legacy BIOS firmware typically used in Windows 7/8 systems to the more powerful Unified Extensible Firmware Interface (UEFI) technology. UEFI is required to enable key enterprise security features available in Windows 10.

* MBR to GPT – Secure 10 now includes support for the MBR2GPT.exe tool, which helps convert the disk layout on a PC from the legacy Master Boot Record (MBR) to GUID Partition Table (GPT). The new tool is the only Microsoft-supported tool to convert a production disk from MBR to GPT without data loss, greatly speeding in-place upgrades to Windows 10.

* WinPE Pre-staging – Microsoft recently introduced the capability to pre-stage a WinPE boot image to a partition from within an SCCM Task Sequence and have that image persist during the conversion from MBR to GPT. Secure 10 supports this capability for refresh/replace scenarios.