WinIPT

The Windows Library for Intel Process Trace (WinIPT) is a project that leverages the new Intel Processor Trace functionality exposed by Windows 10 October Update (Version 1809 / Redstone 5). The new operating system now includes the old inbox Intel PT driver (ipt.sys) with additional code that allows configuring both per-process and per-core tracing through an IOCTL and registry mechanism, instead of relying on undocumented ETW internals. In this repository, you will find the following 3 projects:

• libipt This is the Win32 API version of the library which grants access to the IPT Driver/Service IOCTLs that enable per-core and per-process tracing with the new facilities exposed by Windows. This library uses Win32 semantics & notation, and its functions are re-implementations of some of the functions that were found in Dbghelp.dll, Dbgcore.dll, TTDRecordCPU.dll, Faultrep.dll and Ntdll.dll.

• libiptnt This is the native NT API version of the same library as above, which uses only Ntdll.dll functions, making it suitable for use in Native/non-Win32 applications. This library uses NT-style semantics & notication, and its functions are almost identical to the ones exposed by the libraries listed above.

• ipttool This acts as a sample for the libipt static library referenced above, and provides a simple CLI utility around starting, stopping, and querying traces for a given process. It does not currently support core tracing, and it does not do decoding -- please use the Intel PT library for that.

Screenshot

Motivation

Existing Windows-focused research on Intel Processor Trace has resulted in many hand-crafted custom drivers to toggle the correct flags in the appropriate MSRs, and to register for performance interrupts to correctly handle delivery of tracing data. Unfortunately, most of these custom drivers suffer from security vulnerabilities, academic/proof-of-concept quality code, and don't handle edge and corner cases safely (as would be expected of non-commercial, paid, software!). Additionally, the techniques they use for enabling such functionality closely mimic malicious code, making it hard for defenders to distinguish between the intent of an Intel PT tracing driver, and a rootkit.

Likely in response, in Windows 10 Spring Update (Version 1803 / Redstone 4), Microsoft added an Ipt.sys driver that enables Intel PT support for certain classes of ETW tracing operations. The support was incomplete, and mainly to handle this specific use case. In Windows 10 October Update (Version 1809 / Redstone 5), however, Microsoft has enhanced this driver to support non-ETW-based usage of Intel PT, and to configure both per-process (per-thread) tracing as well as full per-core tracing, exposing many (but not all) of the Intel PT controls that normally get written into the appropriate MSR (such as allowing callers to enable MTC/TSC timing packets, or by configuring either Ring 0 or Ring 3 tracing).

Currently, this support seems to be specific to PSS/OCA scenarios (Microsoft's crash analytics framework part of Windows Error Reporting, or WER) and Time Travel Debugging (TTD/Nirvana) and undocumented, exposed only through a few external exports inside of Ntdll.dll and internal APIs inside of Faultrep.dll. As a result, I reverse engineered the internal IOCTL interface, the exported APIs, the tracing options and headers, and provide this library so that it may help those building PT-based tools to focus on the tracing data, and avoid having to become kernel programmers.

Caveat

As per my previous note on existing drivers being of PoC-level quality, this repository is also a PoC and all of the libraries and tool presented here are provided with zero guarantees on their functionality, and no support (I will, however, strive to address PRs and other helpful comments!). Please do not ship commercial/enteprise/paid products using this library -- I am sure Microsoft and Intel will eventually ship an official set of APIs or SDK for such purposes.

References

The official specification of Intel Processor Trace is available from Intel and shoudl be perused if this is your first time learning about this technology.

For some highly recommended reading on potential applications to security, I suggest reading the following presentations from Richard Johnson & Andrea Alevi: Go Speed Tracer, Harnessing Intel Processor Trace on Windows for Vulnerability Disclosure as well as this presentation: COFI Break by Shlomi Oberman and Ron Shina.

You can also get the unofficial driver which Andrea and Richard collaborated on from GitHub.

Other relevant research on Intel PT security applications can be found from Microsoft Research GRIFFIN and from Shanghai University FlowGuard.

If you would like to know more about my research or work, I invite you to check out my blog at http://www.alex-ionescu.com as well as my training & consulting company, Winsider Seminars & Solutions Inc., at http://www.windows-internals.com.

License

Copyright 2018 Alex Ionescu. All rights reserved. 

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