#VU31985 Out-of-bounds read in Xen - CVE-2017-7228

Vulnerability identifier: #VU31985

Vulnerability risk: Low

CVSSv4.0: 2 [CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2017-7228

CWE-ID: CWE-125

Exploitation vector: Local network

Exploit availability: Yes

Vulnerable software:
Xen
Server applications / Virtualization software

Vendor: Xen Project

Description

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

An issue (known as XSA-212) was discovered in Xen, with fixes available for 4.8.x, 4.7.x, 4.6.x, 4.5.x, and 4.4.x. The earlier XSA-29 fix introduced an insufficient check on XENMEM_exchange input, allowing the caller to drive hypervisor memory accesses outside of the guest provided input/output arrays.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Xen: 4.4.0 - 4.8.5

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External links
https://openwall.com/lists/oss-security/2017/04/04/3
https://www.debian.org/security/2017/dsa-3847
https://www.securityfocus.com/bid/97375
https://www.securitytracker.com/id/1038223
https://xenbits.xen.org/xsa/advisory-212.html
https://github.com/QubesOS/qubes-secpack/blob/master/QSBs/qsb-029-2017.txt
https://googleprojectzero.blogspot.com/2017/04/pandavirtualization-exploiting-xen.html
https://www.exploit-db.com/exploits/41870/

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the local network (LAN).

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.