SB2021030940 - Multiple vulnerabilities in Microsoft Excel

Description

This security bulletin contains information about 2 secuirty vulnerabilities.

1) Use-after-free (CVE-ID: CVE-2021-27054)

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a use-after-free error when processing XLS files. A remote attacker can create a specially crafted Excel file, trick the victim into opening it, trigger a use-after-free error and execute arbitrary code on the system.

Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.

2) Code Injection (CVE-ID: CVE-2021-27053)

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

The vulnerability exists due to improper input validation in the Microsoft Excel. A remote attacker can send a specially crafted request and execute arbitrary code on the target system.

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

Remediation

Install update from vendor's website.

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-27054
• https://www.zerodayinitiative.com/advisories/ZDI-21-507/
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-27053