SB2023011045 - Multiple vulnerabilities in Microsoft Exchange Server

Description

This security bulletin contains information about 5 vulnerabilities.

1) Man-in-the-Middle (MitM) attack (CVE-ID: CVE-2023-21745)

CWE-ID: CWE-300 - Channel Accessible by Non-Endpoint ('Man-in-the-Middle')

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

The vulnerability allows a remote user to perform spoofing attack.

The vulnerability exists due to unspecified error. A remote user on the local network can perform spoofing attack.

2) Information disclosure (CVE-ID: CVE-2023-21761)

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

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/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 attacker can gain unauthorized access to sensitive information on the system.

3) Man-in-the-Middle (MitM) attack (CVE-ID: CVE-2023-21762)

CWE-ID: CWE-300 - Channel Accessible by Non-Endpoint ('Man-in-the-Middle')

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

The vulnerability allows a remote user to perform MitM attack.

The vulnerability exists due to unspecified error. A remote user on the local network can perform spoofing attack and obtain NTLM hashes of other Exchange users.

4) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2023-21763)

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

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

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to improperly imposed security restrictions. A local user can execute arbitrary code with SYSTEM privileges.

5) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2023-21764)

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

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

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to improperly imposed security restrictions. A local user can execute arbitrary code with SYSTEM privileges.

Remediation

Install update from vendor's website.

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2023-21745
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2023-21761
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2023-21762
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2023-21763
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2023-21764