SB2018071022 - Remote code execution in Skype for Business and Lync

Description

This security bulletin contains information about 2 vulnerabilities.

1) Buffer overflow (CVE-ID: CVE-2018-8311)

CWE-ID: CWE-119 - Memory corruption

CVSSv4: 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

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.

2) Improper input validation (CVE-ID: CVE-2018-8238)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: 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

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.

Remediation

Install update from vendor's website.

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8311
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8238