Attacker Value
High
(1 user assessed)
Exploitability
Very High
(1 user assessed)
User Interaction
None
Privileges Required
None
Attack Vector
Network
3

CVE-2021-33766 ProxyToken

Disclosure Date: July 14, 2021
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

Description

Microsoft Exchange Information Disclosure Vulnerability

Add Assessment

3
Ratings
  • Attacker Value
    High
  • Exploitability
    Very High
Technical Analysis

An unauthenticated actor can perform configuration actions on mailboxes belonging to arbitrary users. Which can be used to copy all emails addressed to a target and account and forward them to an account controlled by the threat actor.

https://www.zerodayinitiative.com/blog/2021/8/30/proxytoken-an-authentication-bypass-in-microsoft-exchange-server

CVSS V3 Severity and Metrics
Base Score:
7.5 High
Impact Score:
3.6
Exploitability Score:
3.9
Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack Vector (AV):
Network
Attack Complexity (AC):
Low
Privileges Required (PR):
None
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
High
Integrity (I):
None
Availability (A):
None

General Information

Vendors

  • Microsoft

Products

  • Microsoft Exchange Server 2019 Cumulative Update 9,
  • Microsoft Exchange Server 2016 Cumulative Update 20,
  • Microsoft Exchange Server 2013,
  • Microsoft Exchange Server 2016 Cumulative Update 19,
  • Microsoft Exchange Server 2019 Cumulative Update 8

Additional Info

Technical Analysis