CVE-2021-42237
published 2021-11-05CVE-2021-42237: Sitecore XP 7.5 Initial Release to Sitecore XP 8.2 Update-7 is vulnerable to an insecure deserialization attack where it is possible to achieve remote command…
PriorityP198critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
KEVITWEXPLOITRansomwareInitial access
CISA Known Exploited Vulnerabilitydue 2022-04-15
Exploited in the wild
EPSS
99.21%
99.9th percentile
Sitecore XP 7.5 Initial Release to Sitecore XP 8.2 Update-7 is vulnerable to an insecure deserialization attack where it is possible to achieve remote command execution on the machine. No authentication or special configuration is required to exploit this vulnerability.
Affected
4 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| sitecore | experience_platform | — | — |
| sitecore | experience_platform | — | — |
| sitecore | experience_platform | — | — |
| sitecore | experience_platform | — | — |
Detection & IOCsextracted from sources · hover to see the quote
snort
alert http any any -> $HOME_NET any (msg:"ET WEB_SPECIFIC_APPS Sitecore XP Unauthenticated Remote Code Execution in Report.ashx (CVE-2021-42237)"; flow:established,to_server; http.uri; content:"/sitecore/shell/ClientBin/Reporting/Report.ashx"; fast_pattern; http.request_body; content:""; content:"Serialization/Arrays|22|"; distance:0; pcre:"/^[^\x3e]*?\x3e(?:cmd|pwsh|powershell)/R"; http.method; content:"POST"; reference:url,www.assetnote.io/resources/research/sitecore-experience-platform-pre-auth-rce-cve-2021-42237; reference:cve,2021-42237; classtype:web-application-attack; sid:2065043; rev:1; metadata:affected_product Sitecore, attack_target Server, tls_state TLSDecrypt, created_at 2025_10_03, cve CVE_2021_42237, deployment Perimeter, deployment Internal, deployment SSLDecrypt, confidence High, signature_severity Major, tag Exploit, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2025_10_03, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application; target:dest_ip;)
- →Target endpoint is Report.ashx; look for unauthenticated HTTP POST requests to /sitecore/shell/ClientBin/Reporting/Report.ashx with Content-Type: text/xml containing a deserialization payload (NetDataContractSerializer / TypeConfuseDelegate gadget chain). ↗
- →Request body will contain XML with 'Serialization/Arrays' namespace and a 'parameters'/'parameter' XML tag structure triggering NetDataContractSerializer.ReadObject deserialization. ↗
- →Exploit uses the TypeConfuseDelegate gadget chain via System.Diagnostics.Process.Start to execute OS commands (cmd, pwsh, powershell); detect process spawning from IIS worker process (w3wp.exe) invoking cmd.exe or powershell.exe. ↗
- →Successful exploitation response body contains 'System.ArgumentNullException'; use this as a secondary confirmation indicator alongside DNS/OOB interaction. ↗
- →Shodan/FOFA fingerprinting: exposed Sitecore instances can be identified via HTTP title 'SiteCore' or 'sitecore'; use as asset discovery pivot before hunting for exploitation attempts. ↗
- →Post-exploitation privilege escalation: attacker may use 'getsystem' technique 4 (RPCSS impersonation) to escalate from NT AUTHORITY\NETWORK SERVICE to SYSTEM; monitor for RPCSS impersonation events. ↗
- ·Vulnerability exists only in Sitecore XP 7.5.0 through 8.2 Update-7; versions 7.2.6 and earlier and 9.0 and later are NOT affected. Confirm version before applying detections to avoid false positives. ↗
- ·No authentication or special configuration is required to exploit this vulnerability; the vulnerable ProcessRequest() handler does not check authentication before calling DeserializeQuery(). ↗
- ·The Snort/ET rule (sid:2065043) requires TLS decryption (tls_state TLSDecrypt / deployment SSLDecrypt) to inspect encrypted HTTPS traffic; detections will be blind on TLS-terminated sessions without SSL inspection. ↗
CVSS provenance
nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvdv2.010.0CRITICALAV:N/AC:L/Au:N/C:C/I:C/A:C
vulncheck9.8CRITICAL
cisa9.8CRITICAL
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CISA
Sitecore XP Remote Command Execution Vulnerability
cisa·2022-03-25·CVSS 9.8
CVE-2021-42237 [CRITICAL] CWE-502 Sitecore XP Remote Command Execution Vulnerability
Vulnerability: Sitecore XP Remote Command Execution Vulnerability
Affected: Sitecore XP
Sitcore XP contains an insecure deserialization vulnerability which can allow for remote code execution.
Required Action: Apply updates per vendor instructions.
Notes: https://nvd.nist.gov/vuln/detail/CVE-2021-42237
Remediation Due Date: 2022-04-15
GHSA
GHSA-j3x5-fr4h-9v7v: Sitecore XP 7
ghsa_unreviewed·2022-05-24
CVE-2021-42237 [CRITICAL] CWE-502 GHSA-j3x5-fr4h-9v7v: Sitecore XP 7
Sitecore XP 7.5 Initial Release to Sitecore XP 8.2 Update-7 is vulnerable to an insecure deserialization attack where it is possible to achieve remote command execution on the machine. No authentication or special configuration is required to exploit this vulnerability.
VulnCheck
Sitecore XP Remote Command Execution Vulnerability
vulncheck·2021·CVSS 9.8
CVE-2021-42237 [CRITICAL] CWE-502 Sitecore XP Remote Command Execution Vulnerability
Sitecore XP Remote Command Execution Vulnerability
Sitcore XP contains an insecure deserialization vulnerability which can allow for remote code execution.
Affected: Sitecore XP
Required Action: Apply updates per vendor instructions.
Known Ransomware Campaign Use: Known
Exploitation References: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json; https://cisa.gov/news-events/alerts/2022/04/27/2021-top-routinely-exploited-vulnerabilities; https://cisa.gov/news-events/cybersecurity-advisories/aa22-117a; https://unit42.paloaltonetworks.com/network-security-trends-cross-site-scripting/; https://www.cisa.gov/uscert/ncas/alerts/aa22-279a; https://www.secureworks.com/research/gold-melody-profile-of-an-initial-access-broker; https://www.secureworks.com/research
Suricata
ET WEB_SPECIFIC_APPS Sitecore XP Unauthenticated Remote Code Execution in Report.ashx (CVE-2021-42237)
suricata·2025-10-03·CVSS 9.8
CVE-2021-42237 [CRITICAL] ET WEB_SPECIFIC_APPS Sitecore XP Unauthenticated Remote Code Execution in Report.ashx (CVE-2021-42237)
ET WEB_SPECIFIC_APPS Sitecore XP Unauthenticated Remote Code Execution in Report.ashx (CVE-2021-42237)
Rule: alert http any any -> $HOME_NET any (msg:"ET WEB_SPECIFIC_APPS Sitecore XP Unauthenticated Remote Code Execution in Report.ashx (CVE-2021-42237)"; flow:established,to_server; http.uri; content:"/sitecore/shell/ClientBin/Reporting/Report.ashx"; fast_pattern; http.request_body; content:""; content:"Serialization/Arrays|22|"; distance:0; pcre:"/^[^\x3e]*?\x3e(?:cmd|pwsh|powershell)/R"; http.method; content:"POST"; reference:url,www.assetnote.io/resources/research/sitecore-experience-platform-pre-auth-rce-cve-2021-42237; reference:cve,2021-42237; classtype:web-application-attack; sid:2065043; rev:1; metadata:affected_product Sitecore, attack_target Server, tls_state TLSDecrypt, created
Nuclei
Sitecore Experience Platform Pre-Auth RCE
nuclei·CVSS 9.8
CVE-2021-42237 [CRITICAL] Sitecore Experience Platform Pre-Auth RCE
Sitecore Experience Platform Pre-Auth RCE
Sitecore XP 7.5 to Sitecore XP 8.2 Update 7 is vulnerable to an insecure deserialization attack where remote commands can be executed by an attacker with no authentication or special configuration required.
Template:
id: CVE-2021-42237
info:
name: Sitecore Experience Platform Pre-Auth RCE
author: pdteam
severity: critical
description: Sitecore XP 7.5 to Sitecore XP 8.2 Update 7 is vulnerable to an insecure deserialization attack where remote commands can be executed by an attacker with no authentication or special configuration required.
impact: |
Successful exploitation of this vulnerability could allow an attacker to execute arbitrary code on the affected system.
remediation: For Sitecore XP 7.5.0 - Sitecore XP 7.5.2, use one of the following
Metasploit
Sitecore Experience Platform (XP) PreAuth Deserialization RCE
metasploit
Sitecore Experience Platform (XP) PreAuth Deserialization RCE
Sitecore Experience Platform (XP) PreAuth Deserialization RCE
This module exploits a deserialization vulnerability in the Report.ashx page of Sitecore XP 7.5 to 7.5.2, 8.0 to 8.0.7, 8.1 to 8.1.3, and 8.2 to 8.2.7. Versions 7.2.6 and earlier and 9.0 and later are not affected. The vulnerability occurs due to Report.ashx's handler, located in Sitecore.Xdb.Client.dll under the Sitecore.sitecore.shell.ClientBin.Reporting.Report defintion, having a ProcessRequest() handler that calls ProcessReport() with the context of the attacker's request without properly checking if the attacker is authenticated or not. This request then causes ReportDataSerializer.DeserializeQuery() to be called, which will end up calling the DeserializeParameters() function of Sitecore.Analytics.Reporting.ReportDataSeria
Qualys
NSA Alert: Topmost CVEs Actively Exploited By People’s Republic of China State-Sponsored Cyber Actors
blogs_qualys·2022-10-07·CVSS 10.0
[CRITICAL] NSA Alert: Topmost CVEs Actively Exploited By People’s Republic of China State-Sponsored Cyber Actors
## Table of Contents
Detect & Prioritize 20 Publicly Known Vulnerabilities using VMDR 2.0
Identify Vulnerable Assets using Qualys Threat Protection
Recommendations & Mitigations
Contributors
On October 6, 2022, the United States National Security Agency (NSA) released a cybersecurity advisory on the Chinese government—officially known as the People’s Republic of China (PRC) states-sponsored cyber actors’ activity to seek national interests. These malicious cyber activities attributed to the Chinese government targeted, and persist to target, a mixture of industries and organizations in the United States. They provide the top CVEs used since 2020 by the People’s Republic of China (PRC) states-sponsored cyber actors as evaluated by the National Security Agency (NSA), Cybersecurity and I
Qualys
NSA Alert: Topmost CVEs Actively Exploited By PRC Sponsored Cyber Actors | Qualys
blogs_qualys·2022-10-07
NSA Alert: Topmost CVEs Actively Exploited By PRC Sponsored Cyber Actors | Qualys
#### Table of Contents
- Detect & Prioritize 20 Publicly Known Vulnerabilities using VMDR 2.0
- Identify Vulnerable Assets using Qualys Threat Protection
- Recommendations & Mitigations
- Contributors
On October 6, 2022, the United States National Security Agency (NSA) released a cybersecurity advisory on the Chinese government—officially known as the People’s Republic of China (PRC) states-sponsored cyber actors’ activity to seek national interests. These malicious cyber activities attributed to the Chinese government targeted, and persist to target, a mixture of industries and organizations in the United States. They provide the top CVEs used since 2020 by the People’s Republic of China (PRC) states-sponsored cyber actors as evaluated by the National Security Agency (NSA), Cybersecurit
Tenable
Top 20 CVEs Exploited by People's Republic of China State-Sponsored Actors (AA22-279A)
blogs_tenable·2022-10-07
Top 20 CVEs Exploited by People's Republic of China State-Sponsored Actors (AA22-279A)
## Cloud Exposure
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## Business needs
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Unit42
Network Security Trends: November 2021 to January 2022
blogs_unit42·2022-05-31
Network Security Trends: November 2021 to January 2022
Threat Research Center
Threat Research
Vulnerabilities
## Network Security Trends: November 2021 to January 2022
Yue Guan
Published: May 31, 2022
Threat Research
Vulnerabilities
Apache Log4j
Attack analysis
Denial of service
Exploit in Wild
Network security trends
## Executive Summary
Unit 42 researchers continually observe network attacks and search for insights that can assist defenders. Here, we summarize key trends from November 2021 to January 2022. In the following sections, we present our analysis of the most recently published vulnerabilities, including the severity distribution. We also classify vulnerabilities to provide a clear view of the prevalence of, for example, cross-site scripting or denial of service.
Cross-site scripting stood out as a commonly used t
Unit42
Network Security Trends: November 2021 to January 2022
blogs_unit42·2022-05-31·CVSS 9.8
[CRITICAL] Network Security Trends: November 2021 to January 2022
## Executive Summary
Unit 42 researchers continually observe network attacks and search for insights that can assist defenders. Here, we summarize key trends from November 2021 to January 2022. In the following sections, we present our analysis of the most recently published vulnerabilities, including the severity distribution. We also classify vulnerabilities to provide a clear view of the prevalence of, for example, cross-site scripting or denial of service.
Cross-site scripting stood out as a commonly used technique. Among around 6,443 newly published vulnerabilities, we found that a large portion (almost 10.6%) still involve this technique. However, by evaluating around 167 million attack sessions and focusing on the latest exploits in the wild, we conclude that remote code execution
Checkpoint
15th November – Threat Intelligence Report
blogs_checkpoint·2021-11-15
CVE-2021-42237 15th November – Threat Intelligence Report
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## 15th November – Threat Intelligence Report
For the latest discoveries in cyber research for the week of 15th November, please download our Threat Intelligence Bulletin .
Top Attacks and Breaches
Check Point Research notes a 178% increase in the number of malicious shopping websites, compared to the rest of the year, spotting over 5300 different malicious websites per week ahead of the end of this year’s e-shopping season.
Check Point Research has analyzed the operations of threat actor MosesStaff following its
http://packetstormsecurity.com/files/164988/Sitecore-Experience-Platform-XP-Remote-Code-Execution.htmlhttp://sitecore.comhttps://blog.assetnote.io/2021/11/02/sitecore-rce/https://support.sitecore.com/kb?id=kb_article_view&sysparm_article=KB1000776http://packetstormsecurity.com/files/164988/Sitecore-Experience-Platform-XP-Remote-Code-Execution.htmlhttp://sitecore.comhttps://blog.assetnote.io/2021/11/02/sitecore-rce/https://support.sitecore.com/kb?id=kb_article_view&sysparm_article=KB1000776https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-42237
2021-11-05
Published
2022-03-25
Added to CISA KEV
Exploited in the wild