⚠ Actively exploited in ransomware campaigns
This vulnerability is on the CISA Known Exploited Vulnerabilities list and has been used in known ransomware attacks. CISA required action: Apply updates per vendor instructions.. Due date: 2021-11-17.

CVE-2021-34523

CWE-269 — Improper Privilege ManagementCWE-287 — Improper Authentication12 documents10 sources
Severity
9.8CRITICAL
EPSS
94.0%
top 0.11%
CISA KEV
KEVRansomware
Added 2021-11-03
Due 2021-11-17
Exploit
Exploited in wild
Active exploitation observed
Affected products
6
Microsoft Microsoft Exchange Server 2013 Cumulative Update 23Microsoft Microsoft Exchange Server 2016 Cumulative Update 19Microsoft Microsoft Exchange Server 2016 Cumulative Update 20+3 more
Timeline
PublishedJul 14
KEV addedNov 3
KEV dueNov 17
Latest updateJul 30
CISA Required Action: Apply updates per vendor instructions.

Description

Microsoft Exchange Server Elevation of Privilege Vulnerability

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:NExploitability: 2.5 | Impact: 5.8

Affected Packages6 packages

Patches

Patch: portal.msrc.microsoft.com ↗Patch: portal.msrc.microsoft.com ↗

🔴Vulnerability Details

3
GHSA
GHSA-gcrr-725q-f8jw: Microsoft Exchange Server Elevation of Privilege Vulnerability This CVE ID is unique from CVE-2021-33768, CVE-2021-34470↗2022-05-24
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CVEList
Microsoft Exchange Server Elevation of Privilege Vulnerability↗2021-07-14
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VulnCheck
Microsoft Exchange Server Privilege Escalation Vulnerability↗2021
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💥Exploits & PoCs

1
Metasploit
Microsoft Exchange ProxyShell RCE↗
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📋Vendor Advisories

2
CISA
Microsoft Exchange Server Privilege Escalation Vulnerability↗2021-11-03
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Microsoft
Microsoft Exchange Server Elevation of Privilege Vulnerability↗2021-07-13
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🕵️Threat Intelligence

3
Bleepingcomputer
UK govt links 2021 Electoral Commission breach to Exchange server↗2024-07-30
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Elastic
Detection and response for the actively exploited ProxyShell vulnerabilities — Elastic Security Labs↗2022-06-02
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Elastic
Detection and response for the actively exploited ProxyShell vulnerabilities — Elastic Security Labs↗2022-06-02
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CVE-2021-34523 (CRITICAL CVSS 9.8) | Microsoft Exchange Server Elevation | cvebase.io