Monthly Archives: February 2017

How To Shrink Attack Surfaces with a Hypervisor

A software environment’s attack surface is defined as the sum of points in which an unauthorized user or malicious adversary can enter or extract data. The smaller the attack surface, the better. recently sat down with Doug Goldstein ( or @doug_goldstein) to discuss how companies can use hypervisors to reduce attack surfaces and why the Xen Project hypervisor is a perfect choice for security-first environments. Doug is a principal software engineer at Star Lab, a company focused on providing software protection and integrity solutions for embedded systems.

You can read the full interview here.

Request for Comment: Scope of Vulnerabilities for which XSAs are issued

Issuing advisories has a cost: It costs the security team significant amounts of time to craft and send the advisories; it costs many of our downstreams time to apply, build, and test patches; and it costs many of our users time to decide whether to do an update, and if so, to test and deploy it.

Given this, the Xen Project Security Team wants to clarify when they should issue an advisory or not: the Xen Security Response Process only mentions “‘vulnerabilities”, without specifying what constitutes a vulnerability.

We would like guidelines from the community about what sorts of issues should be considered security issues (and thus will have advisories issued). I have posted the second version a draft of a section I am proposing to be added to the Xen Security Policy to xen-devel; a copy is included below for your convenience. There are only minor modifications from the first draft, so barring major feedback from the wider community it will likely achieve consensus. If you want input, now is the time to speak up.

Most of it is just encoding long-established practice. But there are two key changes and / or clarifications that deserve attention and discussion:

    Criteria 2c: Leaking of mundane information from Xen or dom0 will not be considered a security issue unless it may contain sensitive guest or user data

Criteria 4: If no operating systems are vulnerable to a bug, no advisory will be issued.

If you want to weigh in on the question, please join the discussion on xen-devel before 28 February. The title of the thread is “RFC v2: Scope of Vulnerabilities for which XSAs are issued”.

Continue reading