Microsoft has launched a bug bounty program for ASP.NET and .NET Core, its open-source web application framework for Windows, Linux, and OS X.

.NET Core is a fork of the Windows-only .NET Framework and is still in beta, as is ASP.NET 5, for which beta 8 was released earlier this month. The company will pay from $500 to $15,000 for security bug submissions that meet its criteria. Bugs must be vulnerability flaws that are newly discovered and disclosed to Microsoft before being publicized elsewhere. Fees are based on the severity of the bug, the quality of the report, and whether or not a functioning exploit is included. The program runs for three months, from October 20th 2015 to January 20th 2016.

A table lists the various categories of vulnerability that will be considered, including remote code execution (reckoned to be the most severe), elevation of privilege, remote DoS (denial of service), tampering and spoofing, information leaks, and cross-site scripting faults in ASP.NET templates.

Who decides whether a particular bug is eligible and what it is worth? You guessed right: "Microsoft retains sole discretion in determining which submissions are qualified."

Only the latest public beta code is eligible, and the program only covers ASP.NET 5 and .NET Core, not the Windows-only release of ASP.NET. Microsoft is also excluding the "networking stack on Linux and OS X," though it plans to add this to the program "once our cross-platform networking stack matches the stability and security it has on Windows," according to security lead for ASP.NET, Barry Dorrans.

Why is Microsoft so keen to put money behind an open source project that may result in ASP.NET sites running on non-Windows servers? Presumably the company is betting that developers using its web application framework, even in open source guise, will find themselves drawn towards hosting on Azure, or using a SQL Server database, or linking with Microsoft services such as Office 365 or Azure Active Directory.®