SB2021020930 - Multiple vulnerabilities in Microsoft SharePoint

Description

This security bulletin contains information about 4 vulnerabilities.

1) Information disclosure (CVE-ID: CVE-2021-24071)

CWE-ID: CWE-200 - Exposure of sensitive information to an unauthorized actor

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to excessive data output by the application. A remote authenticated attacker can gain unauthorized access to sensitive information on the system.

2) Input validation error (CVE-ID: CVE-2021-24066)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green

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

The vulnerability exists due to insufficient validation of user-supplied input in Microsoft SharePoint. A remote authenticated attacker can create a site using specific code and execute arbitrary code on the target system.

3) Spoofing attack (CVE-ID: CVE-2021-1726)

CWE-ID: CWE-451 - User Interface (UI) Misrepresentation of Critical Information (Clickjacking, spoofing)

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to perform spoofing attack.

The vulnerability exists due to incorrect processing of user-supplied data in Microsoft SharePoint within the blog sharing functionality. A remote authenticated attacker can spoof page content.

4) Input validation error (CVE-ID: CVE-2021-24072)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green

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

The vulnerability exists due to insufficient validation of user-supplied input in Microsoft SharePoint Server. A remote authenticated attacker can pass specially crafted input to the application and execute arbitrary code on the target system.

Remediation

Install update from vendor's website.

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-24071
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-24066
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-1726
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-24072