Remote code execution in Skype for Business and Lync

Published: 2018-07-10

Risk	High
Patch available	YES
Number of vulnerabilities	2
CVE-ID	CVE-2018-8311 CVE-2018-8238
CWE-ID	CWE-119 CWE-20
Exploitation vector	Network
Public exploit	N/A
Vulnerable software	Skype for Business Client/Desktop applications / Messaging software Microsoft Lync Client/Desktop applications / Messaging software
Vendor	Microsoft

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Buffer overflow

EUVDB-ID: #VU13787

Risk: High

CVSSv4.0: 5.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2018-8311

CWE-ID: CWE-119 - Memory corruption

Exploit availability: No

Description

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

The vulnerability exists due to a boundary error when processing untrusted content. A remote attacker can create a specially crafted Office document, trick the victim into opening it, trigger memory corruption and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Skype for Business: 2016

Microsoft Lync: 2013

CPE2.3

External links

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8311

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.

2) Improper input validation

EUVDB-ID: #VU13789

Risk: Medium

CVSSv4.0: 4 [CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2018-8238

CWE-ID: CWE-20 - Improper input validation