{"id":7245,"date":"2017-04-05T10:30:02","date_gmt":"2017-04-05T18:30:02","guid":{"rendered":"http:\/\/www.palada.net\/index.php\/2017\/04\/05\/news-1036\/"},"modified":"2017-04-05T10:30:02","modified_gmt":"2017-04-05T18:30:02","slug":"news-1036","status":"publish","type":"post","link":"https:\/\/www.palada.net\/index.php\/2017\/04\/05\/news-1036\/","title":{"rendered":"Critical Xen hypervisor flaw endangers virtualized environments"},"content":{"rendered":"

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Credit to Author: Lucian Constantin| Date: Wed, 05 Apr 2017 10:59:00 -0700<\/strong><\/p>\n

A critical vulnerability in the widely used Xen hypervisor allows attackers to break out of a guest operating system running inside a virtual machine and access the host system’s entire memory.<\/p>\n

This is a serious violation of the security barrier enforced by the hypervisor and poses a particular threat to multi-tenant data centers where the customers’ virtualized servers share the same underlying hardware.<\/p>\n

The open-source Xen hypervisor is used by cloud computing providers and virtual private server hosting companies, as well as by security-oriented operating systems like Qubes OS.<\/p>\n

The new vulnerability<\/a> affects Xen 4.8.x, 4.7.x, 4.6.x, 4.5.x, and 4.4.x and has existed in the Xen code base for over four years. It was unintentionally introduced in December 2012 as part of a fix for a different issue.<\/p>\n

The Xen project released a patch Tuesday that can be applied manually to vulnerable deployments. The good news is that the vulnerability can only be exploited from 64-bit paravirtualized guest operating systems.<\/p>\n

Xen supports two types of virtual machines: Hardware Virtual Machines (HVMs), which use hardware-assisted virtualization, and paravirtualized (PV) VMs that use software-based virtualization. Based on whether they use PV VMs, Xen users might be affected or not.<\/p>\n

For example, Amazon Web Services said in an advisory<\/a> that its customers’ data and instances were not affected by this vulnerability and no customer action is required. Meanwhile, virtual private server provider Linode had to reboot<\/a> some of its legacy Xen servers in order to apply the fix.<\/p>\n

Qubes OS, an operating system that uses Xen to isolate applications inside virtual machines, also put out an advisory<\/a> warning that an attacker who exploits another vulnerability, for example inside a browser, can exploit this Xen issue to compromise the whole Qubes system.<\/p>\n

The Qubes developers have released a patched Xen package for Qubes 3.1 and 3.2 and reiterated their intention to stop using paravirtualization altogether in the upcoming Qubes 4.0.<\/p>\n

Vulnerabilities that allow breaking the isolation layer of virtual machines can be very valuable for attackers. The recent Pwn2Own hacking contest offered a $100,000 reward<\/a>\u00a0for virtual machine escapes in VMware Workstation or Microsoft Hyper-V. Exploit acquisition firm Zerodium offers up to $50,000 for such an exploit.<\/p>\n

http:\/\/www.computerworld.com\/category\/security\/index.rss<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

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Credit to Author: Lucian Constantin| Date: Wed, 05 Apr 2017 10:59:00 -0700<\/strong><\/p>\n

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A critical vulnerability in the widely used Xen hypervisor allows attackers to break out of a guest operating system running inside a virtual machine and access the host system’s entire memory.<\/p>\n

This is a serious violation of the security barrier enforced by the hypervisor and poses a particular threat to multi-tenant data centers where the customers’ virtualized servers share the same underlying hardware.<\/p>\n

The open-source Xen hypervisor is used by cloud computing providers and virtual private server hosting companies, as well as by security-oriented operating systems like Qubes OS.<\/p>\n