Microsoft Exchange Server
CVE-2021-34473 — Microsoft Exchange Server Remote Code Execution Vulnerability
Executive Summary
None
Overview
9.1
CVSS CRITICAL
Critical
MS Severity
Not Exploited
MS Exploit Status
More Likely
MS Exploit Likelihood
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C
ATTACK VECTOR
Network
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
None
USER INTERACTION
None
SCOPE
Unchanged
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
None
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 7.9
EPSS Score
No EPSS score available for this CVE.
View on FIRST.orgAffected Products
5 affected products
| Product | KB Article | Severity | Impact | Restart Required |
|---|---|---|---|---|
| Microsoft Exchange Server 2013 Cumulative Update 23 | 5001779 (Security Update) |
Critical | Remote Code Execution | Yes |
| Microsoft Exchange Server 2019 Cumulative Update 9 | 5001779 (Security Update) |
Critical | Remote Code Execution | Yes |
| Microsoft Exchange Server 2016 Cumulative Update 20 | 5001779 (Security Update) |
Critical | Remote Code Execution | Yes |
| Microsoft Exchange Server 2016 Cumulative Update 19 | 5001779 (Security Update) |
Critical | Remote Code Execution | Yes |
| Microsoft Exchange Server 2019 Cumulative Update 8 | 5001779 (Security Update) |
Critical | Remote Code Execution | Yes |
Patches
1 patch
| Article | Type | Restart |
|---|---|---|
5001779 |
Security Update | Yes |
Exploits & PoC
9 public PoCsUnverified third-party code
Public proof-of-concept repositories aggregated from PoC-in-GitHub. They are not reviewed and may be incomplete, non-functional, or malicious — inspect the code before running anything.
| Repository | Stars | Published | Description |
|---|---|---|---|
| horizon3ai/proxyshell | 121 | 2021-09-04 | Proof of Concept for CVE-2021-34473, CVE-2021-34523, and CVE-2021-31207 |
| cyberheartmi9/Proxyshell-Scanner | 46 | 2021-08-10 | nuclei scanner for proxyshell ( CVE-2021-34473 ) |
| kh4sh3i/ProxyShell | 42 | 2022-06-29 | CVE-2021-34473 Microsoft Exchange Server Remote Code Execution Vulnerability |
| p2-98/CVE-2021-34473 | 30 | 2021-08-16 | CVE-2021-34473 Microsoft Exchange Server Remote Code Execution Vulnerability |
| je6k/CVE-2021-34473-Exchange-ProxyShell | 17 | 2021-11-22 | 对Exchange Proxyshell 做了二次修改，精确的拆分、实现辅助性安全测试。 |
| RaouzRouik/CVE-2021-34473-scanner | 5 | 2021-08-11 | Scanner for CVE-2021-34473, ProxyShell, A Microsoft Exchange On-premise Vulnerability |
| ipsBruno/CVE-2021-34473-NMAP-SCANNER | 2 | 2022-11-16 | A massive scanner for CVE-2021-34473 Microsoft Exchange Windows Vulnerability |
| learningsurface/ProxyShell-CVE-2021-34473.py | 0 | 2022-05-24 | A simple script to check for ProxyShell |
| f4alireza/CVE | 0 | 2023-10-17 | Proxyshell for Exploiting CVE-2021-34473 |
Detection Rules
Detection availableCommunity detection & vulnerability-scanning rules aggregated from Sigma and Nuclei templates. Validate and tune to your environment before deploying.
Nuclei templates 1
nuclei -id CVE-2021-34473
Acknowledgments
Orange Tsai(@orange_8361) from DEVCORE Research Team working with Trend Micro Zero Day Initiative
References
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