#VU8757 Privilege escalation in Skype for Business - CVE-2017-11786

Vulnerability identifier: #VU8757

Vulnerability risk: Low

CVSSv4.0: 1.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2017-11786

CWE-ID: CWE-264

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Skype for Business
Client/Desktop applications / Messaging software

Vendor: Microsoft

Description
The vulnerability allows a remote authenticated attacker to gain elevated privileges on the target system.

The weakness exists due to when Skype for Business fails to properly handle specific authentication requests. A remote attacker can invite a user to an instant message session while using a malicious profile image, steal an authentication has and gain system privileges.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Skype for Business: 2016

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External links
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2017-11786

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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 Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.