Microsoft Exchange Server Spoofing Vulnerability

Source data

Overview

Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.

Impact & technical details

Spoofing

How could an attacker exploit this vulnerability? An attacker could send a specially crafted link to a user and persuade them to click it, with no authentication required. If a user with administrative privileges clicks the link, successful exploitation could allow the attacker to perform actions using that user's privileges, potentially allowing access to or modification of organizational data.

According to the CVSS metric, user interaction is required (UI:R). What interaction would the user have to do? Exploitation of the vulnerability requires that a user to open a specially crafted link. An attacker would have no way to force users to click the link. Instead, an attacker would have to convince users to click the link through social engineering.

According to the CVSS metric, a successful exploitation could lead to a scope change (S:C). What does this mean for this vulnerability? The vulnerability is in the web server, but the malicious scripts execute in the victim’s browser on their machine.

CVSS base score

9.3 / 10

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N/E:U/RL:O/RC:C

Highest base score supplied by MSRC for this record; the vector belongs to that score. Ratings can vary by product. Microsoft Important is displayed as High; Moderate is displayed as Medium.

Affected products

• Microsoft Exchange Server 2016 Cumulative Update 23
• Microsoft Exchange Server 2019 Cumulative Update 14
• Microsoft Exchange Server 2019 Cumulative Update 15
• Microsoft Exchange Server Subscription Edition RTM

Source guidance

Remediation

The source provides update references without a separate remediation summary. Review the applicable update links below.

At least one Microsoft vendor-fix reference is available. Check each affected product for its applicable update, prerequisites, and supported version.

Authoritative sources & updates

Findings and update information come from the linked publishers. GTP compiles the public record and provides the recommendation above. CVSS ratings shown here come from Microsoft. NVD references provide additional public context.

• Microsoft Security Response Center (opens in a new tab)
• Microsoft remediation guidance (opens in a new tab)
• Microsoft remediation guidance (opens in a new tab)
• Microsoft remediation guidance (opens in a new tab)
• Microsoft security update · 5128895 (opens in a new tab)
• Microsoft remediation guidance (opens in a new tab)