⚠ 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-2021-31207

CWE-434 — Unrestricted File UploadCWE-20 — Improper Input ValidationCWE-22 — Path Traversal17 documents11 sources
Severity
6.6MEDIUM
EPSS
93.8%
top 0.14%
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
PublishedMay 11
KEV addedNov 3
KEV dueNov 17
Latest updateJul 30
CISA Required Action: Apply updates per vendor instructions.

Description

Microsoft Exchange Server Security Feature Bypass Vulnerability

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:HExploitability: 0.7 | Impact: 5.9

Affected Packages6 packages

Patches

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

🔴Vulnerability Details

3
GHSA
GHSA-jcxv-6f65-7hrx: Microsoft Exchange Server Security Feature Bypass Vulnerability↗2022-05-24
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CVEList
Microsoft Exchange Server Security Feature Bypass Vulnerability↗2021-05-11
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VulnCheck
Microsoft Exchange Server Security Feature Bypass Vulnerability↗2021
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💥Exploits & PoCs

1
Metasploit
Microsoft Exchange ProxyShell RCE↗
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🔍Detection Rules

5
Suricata
ET EXPLOIT Microsoft Exchange SUID Disclosure via SSRF Inbound M2 (CVE-2021-31207)↗2022-03-29
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Suricata
ET EXPLOIT Microsoft Exchange SUID Disclosure via SSRF Inbound M1 (CVE-2021-31207)↗2021-08-10
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Suricata
ET EXPLOIT Vulnerable Microsoft Exchange Server Response (CVE-2021-31207)↗2021-08-09
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Suricata
ET EXPLOIT Microsoft Exchange Pre-Auth Path Confusion M1 (CVE-2021-31207)↗2021-08-09
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Suricata
ET EXPLOIT Microsoft Exchange Pre-Auth Path Confusion M2 (CVE-2021-31207)↗2021-08-09
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📋Vendor Advisories

2
CISA
Microsoft Exchange Server Security Feature Bypass Vulnerability↗2021-11-03
▶
Microsoft
Microsoft Exchange Server Security Feature Bypass Vulnerability↗2021-05-11
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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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