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
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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

CVSSv3.1: 7.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2018-8311

CWE-ID: CWE-119 - Improper Restriction of Operations within the Bounds of a Memory Buffer

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

http://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

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2018-8238

CWE-ID: CWE-20 - Improper Input Validation

Exploit availability: No

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to improper validation of UNC path links shared via messages. A remote attacker can construct a specially crafted link to file, trick the victim into clicking on that link and execute arbitrary code on the target system with privileges of the current user.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Skype for Business: 2016

Microsoft Lync: 2013


CPE2.3 External links

http://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8238

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.



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