CVE-2021-42237 in Sitecore
Summary
by MITRE • 11/05/2021
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.
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Analysis
by VulDB Data Team • 02/03/2025
The vulnerability identified as CVE-2021-42237 represents a critical insecure deserialization flaw affecting Sitecore XP versions from 7.5 Initial Release through 8.2 Update-7. This vulnerability resides within the deserialization mechanism of the Sitecore content management platform, which processes untrusted data without adequate validation or sanitization. The flaw allows attackers to craft malicious serialized objects that, when processed by the application, trigger arbitrary code execution on the underlying server. This represents a severe security weakness that fundamentally undermines the integrity and confidentiality of the affected systems.
The technical implementation of this vulnerability stems from the application's failure to properly validate serialized data inputs during the deserialization process. When Sitecore processes serialized objects containing malicious payloads, the framework automatically deserializes these objects without sufficient security controls to prevent unauthorized code execution. This flaw aligns with CWE-502, which specifically addresses insecure deserialization vulnerabilities where untrusted data is deserialized without proper validation. The attack vector requires no authentication credentials or special configuration, making it particularly dangerous as it can be exploited by any attacker with access to the application's network. The vulnerability operates at the application layer and can be leveraged to execute arbitrary commands with the privileges of the application process, potentially leading to complete system compromise.
The operational impact of this vulnerability is severe and multifaceted across enterprise environments running affected Sitecore versions. Successful exploitation enables attackers to execute commands remotely on the target machine, potentially leading to data exfiltration, system compromise, and lateral movement within the network. The vulnerability's accessibility means that attackers can exploit it without requiring privileged access or specialized knowledge of the system's internal workings. This makes it particularly dangerous in environments where Sitecore applications are exposed to untrusted networks or where multiple applications share common infrastructure. Organizations may face regulatory compliance violations, data breaches, and significant operational disruption when this vulnerability is exploited, as it provides attackers with direct access to critical business applications and their underlying data repositories.
Mitigation strategies for CVE-2021-42237 must address both immediate remediation and long-term security hardening measures. Organizations should immediately apply the vendor-provided patches and updates released to address this vulnerability, as these typically include fixes for the deserialization mechanism and enhanced input validation controls. Network segmentation and access controls should be implemented to limit exposure of affected systems to untrusted networks, while monitoring solutions should be deployed to detect suspicious deserialization activities. The implementation of application whitelisting and runtime application protection mechanisms can provide additional defense-in-depth layers against exploitation attempts. Security teams should also conduct comprehensive vulnerability assessments to identify other potential deserialization vulnerabilities within their Sitecore installations and related applications, as this flaw demonstrates the importance of proper input validation and secure coding practices. Organizations should consider implementing the principle of least privilege for Sitecore application accounts and ensure that all system components are regularly updated to prevent exploitation of similar vulnerabilities in the future. The ATT&CK framework categorizes this vulnerability under the T1059.007 technique for command and script interpreter, as it enables adversaries to execute commands remotely through the vulnerable deserialization mechanism.