SB2020060938 - Multiple vulnerabilities in Microsoft Windows SMBv3 Client/Server

Description

This security bulletin contains information about 2 vulnerabilities.

1) Information disclosure (CVE-ID: CVE-2020-1206)

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:P/U:Green

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

The vulnerability exists due to the way Microsoft Server Message Block 3.1.1 (SMBv3) protocol handles certain requests A remote attacker can send a specially crafted packet to a targeted SMBv3 server gain unauthorized access to sensitive information on the system.

2) Input validation error (CVE-ID: CVE-2020-1284)

CWE-ID: CWE-20 - Improper input validation

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

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to the way Microsoft Server Message Block 3.1.1 (SMBv3) protocol handles certain requests.

To exploit the vulnerability against a server, an authenticated attacker can send a specially crafted packet to a targeted SMBv3 server. To exploit the vulnerability against a client, an unauthenticated attacker would need to configure  malicious SMBv3 server and convince a user to connect to it.

Remediation

Install update from vendor's website.

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1206
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1284