Microsoft Makes Hyper-V Debugging Symbols Public

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In an attempt to improve Hyper-V technology, which Microsoft considers central to the security of its cloud services, the software giant has released Hyper-V debugging symbols to the public.

Microsoft is now offering access to most Hyper-V-related symbols through the public symbol servers, starting with symbols for Windows Server 2016 with an installed April 2018 cumulative update.

“We would like to share with the security community that we have now released debugging symbols for many of the core components in Hyper-V, with some exceptions such as the hypervisor where we would like to avoid our customers taking a dependency on undocumented hypercalls for instance,” Microsoft announced.

This move, the company says, should prove handy for partners building solutions leveraging Hyper-V, for developers attempting to debug specific issues, and to security researchers to better analyze Hyper-V’s implementation and report any vulnerabilities as part of the Microsoft Hyper-V Bounty Program.

Microsoft is offering consistent rewards for vulnerabilities discovered in the Hyper-V client running on Windows 10 (latest builds of Windows Insider Preview slow) and Windows Server 2016 (latest available version).

The highest payouts reach $250,000 for eligible Critical Remote Code Execution bugs in Hypervisor and Host Kernel. Microsoft is also willing to pay up to $20,000 for issues discovered in Remotefx, Legacy Network Adapter (Generation 1) and Fibre Channel Adapter.

At this year’s Pwn2Own hacking competition, Microsoft was willing to pay up to $150,000 for vulnerabilities in the Hyper-V client, the highest rewards offered at the event.

Developers and security researchers interested in learning more on Microsoft’s Hyper-V Bounty Program should head to this TechNet article.

The list of components that now have debugging symbols made public was published by the Microsoft Virtualization team in a blog post last week.

The set is likely to be updated as the company decides to make more symbols public: “With newer releases, we are evaluating whether we can make even more symbols available,” Microsoft’s Lars Iwer notes.

A limited set of virtualization-related symbols that haven’t been released as of now includes storvsp.pdb, vhdparser.pdb, passthroughparser.pdb, hvax64.pdb, hvix64.pdb, and hvloader.pdb.

Related: Microsoft Launches Windows Bug Bounty Program

Related: Hackers Awarded $267,000 at Pwn2Own 2018

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Ionut Arghire is an international correspondent for SecurityWeek.

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