CVE-2020-16969: Microsoft Exchange Information Disclosure Vulnerability

Overview

Severity
High (CVSS 7.1)
CVSS Vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L/E:P/RL:O/RC:C
Category
Information Disclosure
Exploit Status
Not Exploited
Exploitation Likelihood
Less Likely
Patch Tuesday
2020-Oct
Released
2020-10-13
EPSS Score
0.86% (percentile: 75.1%)

Description

An information disclosure vulnerability exists in how Microsoft Exchange validates tokens when handling certain messages. An attacker who successfully exploited the vulnerability could use this to gain further information from a user. To exploit the vulnerability, an attacker could include specially crafted OWA messages that could be loaded, without warning or filtering, from the attacker-controlled URL. This callback vector provides an information disclosure tactic used in web beacons and other types of tracking systems. The security update corrects the way that Exchange handles these token validations.

FAQ

What type of information could be disclosed by this vulnerability? The type of information that could be disclosed if an attacker successfully exploited this vulnerability is data inside the targeted website like IDs, tokens, nonces, and other sensitive information.

Affected Products (5)

Other

  • 11789
  • 11791
  • 11792
  • 11793
  • 11682

Security Updates (1)

Acknowledgments

SURESH C

Revision History

  • 2020-10-13: Information published.