CVE-2021-31195
published 2021-05-11CVE-2021-31195: Microsoft Exchange Server Remote Code Execution Vulnerability
PriorityP276high8.8CVSS 3.1
AVNACLPRNUIRSUCHIHAH
EXPLOIT
EPSS
73.68%
99.4th percentile
Microsoft Exchange Server Remote Code Execution Vulnerability
Affected
13 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| microsoft | exchange_server | — | — |
| microsoft | exchange_server | — | — |
| microsoft | exchange_server | — | — |
| microsoft | microsoft_exchange_server_2013_cumulative_update_23 | >= 15.00.0 < 15.00.1497.018 | 15.00.1497.018 |
| microsoft | microsoft_exchange_server_2016_cumulative_update_19 | >= 15.01.0 < 15.01.2176.014 | 15.01.2176.014 |
| microsoft | microsoft_exchange_server_2016_cumulative_update_20 | >= 15.01.0 < 15.01.2242.010 | 15.01.2242.010 |
| microsoft | microsoft_exchange_server_2019_cumulative_update_8 | >= 15.02.0 < 15.02.0792.015 | 15.02.0792.015 |
| microsoft | microsoft_exchange_server_2019_cumulative_update_9 | >= 15.02.0 < 15.02.0858.012 | 15.02.0858.012 |
| msrc | microsoft_exchange_server_2013_cumulative_update_23 | — | — |
| msrc | microsoft_exchange_server_2016_cumulative_update_19 | — | — |
| msrc | microsoft_exchange_server_2016_cumulative_update_20 | — | — |
| msrc | microsoft_exchange_server_2019_cumulative_update_8 | — | — |
| msrc | microsoft_exchange_server_2019_cumulative_update_9 | — | — |
Detection & IOCsextracted from sources · hover to see the quote
url/owa/auth/frowny.aspx?app=people&et=ServerError&esrc=MasterPage&te=\&refurl=}}};alert(document.domain)//
path/owa/auth/frowny.aspx
- →HTTP GET request to /owa/auth/frowny.aspx with XSS payload in the `refurl` parameter; look for HTTP 500 response containing both 'alert(document.domain)//&et=ServerError' and 'mail/bootr.ashx' in the response body with Content-Type: text/html
- →Identify exposed Microsoft Exchange / OWA instances via Shodan using title 'Outlook' or favicon hash 1768726119
- →Identify exposed Microsoft Exchange / OWA instances via FOFA using title 'outlook' or icon_hash 1768726119
- →Response body reflection of the XSS payload string 'alert(document.domain)//&et=ServerError' alongside 'mail/bootr.ashx' confirms the vulnerable endpoint
- ·The vulnerability is specifically in the `refurl` parameter of frowny.aspx (OWA); exploitation requires user interaction (UI:R) per CVSS scoring, meaning the attacker must trick a victim into visiting a crafted URL
- ·Detection relies on an HTTP 500 status code being returned alongside reflected XSS payload content — a non-500 response would not trigger the matcher even if the endpoint exists
- ·Affected CPE is specifically Microsoft Exchange Server 2013 Cumulative Update 23; other Exchange versions may also be affected per MSRC advisory
CVSS provenance
nvdv3.18.8HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
nvdv2.06.8MEDIUMAV:N/AC:M/Au:N/C:P/I:P/A:P
vendor_msrc6.5MEDIUM
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GHSA
GHSA-q258-48f4-r94w: Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-31195
ghsa_unreviewed·2022-05-24·CVSS 6.5
CVE-2021-31198 [MEDIUM] CWE-20 GHSA-q258-48f4-r94w: Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-31195
Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-31195.
GHSA
GHSA-w3mg-g64h-4h34: Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-31198
ghsa_unreviewed·2022-05-24·CVSS 7.8
CVE-2021-31195 [HIGH] CWE-290 GHSA-w3mg-g64h-4h34: Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-31198
Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-31198.
Microsoft
Microsoft Exchange Server Remote Code Execution Vulnerability
vendor_msrc·2021-05-11·CVSS 6.5
CVE-2021-31195 [MEDIUM] Microsoft Exchange Server Remote Code Execution Vulnerability
Microsoft Exchange Server Remote Code Execution Vulnerability
Microsoft Exchange Server: Microsoft Exchange Server
Microsoft: Microsoft
Impact: Remote Code Execution
Exploit Status: Publicly Disclosed:No;Exploited:No;Latest Software Release:Exploitation Less Likely;Older Software Release:Exploitation Less Likely;DOS:N/A
Reference: http://www.microsoft.com/download/details.aspx?familyid=68b339e9-3040-4da8-8e57-6fd325cfa9ee
Reference: https://support.microsoft.com/help/5003435
Reference: http://www.microsoft.com/download/details.aspx?familyid=0ff8a768-1dfb-4d50-acd4-87f5a1b34e5f
Reference: http://www.microsoft.com/download/details.aspx?familyid=9536f4a0-838b-40a6-b625-36cd7a6229a1
Reference: http://www.microsoft.com/download/details.aspx?familyid=e8857a66-5eb5-4b0e-b938-07eb17c3af1a
No detection rules found.
Nuclei
Microsoft Exchange Server - Cross-Site Scripting
nuclei·CVSS 8.8
CVE-2021-31195 [HIGH] Microsoft Exchange Server - Cross-Site Scripting
Microsoft Exchange Server - Cross-Site Scripting
Microsoft Exchange Server, or OWA, is vulnerable to a cross-site scripting vulnerability in refurl parameter of frowny.asp.
Template:
id: CVE-2021-31195
info:
name: Microsoft Exchange Server - Cross-Site Scripting
author: infosecsanyam
severity: medium
description: Microsoft Exchange Server, or OWA, is vulnerable to a cross-site scripting vulnerability in refurl parameter of frowny.asp.
impact: |
Successful exploitation of this vulnerability could allow an attacker to execute arbitrary script code in the context of the user's browser, potentially leading to session hijacking, data theft, or other malicious activities.
remediation: |
Apply the latest security updates provided by Microsoft to mitigate this vulnerability.
reference:
- https
Securelist
IT threat evolution in Q3 2021. PC statistics
blogs_securelist·2021-11-26
IT threat evolution in Q3 2021. PC statistics
Table of Contents
Quarterly figures
Financial threats
Financial threat statistics
Ransomware programs
Quarterly trends and highlights
Attack on Kaseya and the REvil story
The arrival of BlackMatter: DarkSide restored?
Q3 closures
Exploitation of vulnerabilities and new attack methods
Number of new ransomware modifications
Number of users attacked by ransomware Trojans
Geography of ransomware attacks
Top 10 most common families of ransomware Trojans
Miners
Number of new miner modifications
Number of users attacked by miners
Geography of miner attacks
Vulnerable applications used by cybercriminals during cyberattacks
Quarter highlights
Statistics
Attacks on macOS
Geography of threats for macOS
IoT attacks
IoT threat statistics
Attacks via web resources
Countries tha
Securelist
IT threat evolution in Q3 2021. PC statistics
blogs_securelist·2021-11-26
IT threat evolution in Q3 2021. PC statistics
Table of Contents
- Quarterly figures
- Financial threats
- Ransomware programs
- Number of users attacked by ransomware Trojans
- Geography of ransomware attacks
- Top 10 most common families of ransomware Trojans
- Miners
- Vulnerable applications used by cybercriminals during cyberattacks
- Attacks on macOS
- IoT attacks
- Attacks via web resources
- Local threats
Authors
- AMR
- IT threat evolution Q3 2021
- IT threat evolution in Q3 2021. PC statistics
- IT threat evolution in Q3 2021. Mobile statistics
These statistics are based on detection verdicts of Kaspersky products received from users who consented to providing statistical data.
## Quarterly figures
According to Kaspersky Security Network, in Q3 2021:
- Kaspersky solutions blocked 1,098,968,315 attacks from online reso
Tenable
Microsoft’s May 2021 Patch Tuesday Addresses 55 CVEs (CVE-2021-31166)
blogs_tenable·2021-05-11·CVSS 9.8
[CRITICAL] Microsoft’s May 2021 Patch Tuesday Addresses 55 CVEs (CVE-2021-31166)
## Cloud Exposure
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Tenable Cloud Vulnerability Management Request a demo
Tenable CIEM Request a demo
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## Vulnerability Exposure
Tenable Vulnerability Management Try for free
Tenable Security Center Request a demo
Tenable Web App Scanning Try for free
Tenable Patch Management Request a demo
Tenable Enclave Security Request a demo
Tenable Attack Surface Management Request a demo
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## AI Exposure
Tenable AI Exposure Request a demo
## OT/IoT Exposure
Tenable OT Security Request a demo
## Identity Exposure
Tenable Identity Exposure Request a demo
## Business needs
Active Directory
AI Security Posture Management (AI-SPM)
AWS security
Azure security
Cloud Security Posture Man
Qualys
Microsoft & Adobe Patch Tuesday (May 2021) – Qualys covers 85 Vulnerabilities, 26 Critical
blogs_qualys·2021-05-11·CVSS 9.9
CVE-2021-31181 [CRITICAL] Microsoft & Adobe Patch Tuesday (May 2021) – Qualys covers 85 Vulnerabilities, 26 Critical
## Microsoft Patch Tuesday – May 2021
Microsoft patched 55 CVEs in their May 2021 Patch Tuesday release, of which 4 are rated as critical severity. Three 0-day vulnerability patches were included in the release. As of this publication date, none have been exploited.
Qualys released 12 QIDs on the same day, providing vulnerability detection and patch management coverage (where applicable) for all 55 CVEs and the related KBs.
## Critical Microsoft vulnerabilities patched:
CVE-2021-31181 – SharePoint Remote Code Execution Vulnerability
Microsoft released patches addressing a critical RCE vulnerability in SharePoint (CVE-2021-31181). This CVE has a high likelihood of exploitability and is assigned a CVSSv3 base score of 8.8 by the vendor.
CVE-2021-31166 – HTTP Protocol Stack Remote Code
2021-05-11
Published