Vulnerability identifier: #VU5580

Vulnerability risk: Critical

CVSSv3.1: 9.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:F/RL:O/RC:C]

CVE-ID: CVE-2015-3456

CWE-ID: CWE-119

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Xen
Server applications / Virtualization software

Vendor: Xen Project

Description
The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The weakness exists due to buffer overflow in the Floppy Disk Controller (FDC) emulation. A remote attacker can send specially crafted FDC commands, trigger memory corruption and execute arbitrary code with privileges of the current user.

Successful exploitation of the vulnerability may result in full control of the vulnerable system.

Note: the vulnerability was being actively exploited.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Xen: 4.0.0 - 4.5.0

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External links
http://git.qemu.org/?p=qemu.git;a=commitdiff

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, a fully functional exploit for this vulnerability is available.