Introduction
The following report highlights critical vulnerabilities identified in Sitecore’s Experience Platform (XP) by the vulnerability research firm WatchTowr. These vulnerabilities, affecting versions 10.1 through 10.4.1 [4], pose significant security risks [4] [8], including the potential for remote code execution and unauthorized access, which could lead to data breaches and operational disruptions.
Description
Vulnerability research firm WatchTowr has identified a series of critical vulnerabilities in Sitecore’s Experience Platform (XP), specifically in versions 10.1 through 10.4.1. Among these [5] [6] [7], the most severe is a pre-authentication Remote Code Execution (RCE) vulnerability [4], designated CVE-2025-27218, which arises from unsafe deserialization in the MachineKeyTokenService.IsTokenValid method [2]. This flaw allows unauthenticated attackers to send malicious payloads via the ThumbnailsAccessToken HTTP header [2], leading to arbitrary code execution with the privileges of the Sitecore application pool [2]. This vulnerability was patched in version 10.4.1, but it affects all versions up to 10.4.
In addition to the critical RCE vulnerability, researchers uncovered a hardcoded credential issue involving the internal user account sitecore\ServicesAPI, which has a trivially guessable password of ‘b.’ This hardcoded credential is embedded in the installation database and remains unchanged across all deployments [4], allowing attackers to easily gain authenticated access [4]. Despite the user lacking explicit administrative roles [4], attackers can exploit Sitecore’s authentication mechanisms to generate a valid session cookie [4], bypassing standard permission checks and accessing restricted areas of the application [4]. The presence of this hardcoded password significantly increases the risk of unauthorized access to sensitive information, potentially leading to data breaches and operational disruptions.
Furthermore, two Post-Auth RCE vulnerabilities were discovered: one allows exploitation of the uiUpload pipeline through a file upload mechanism that lacks proper validation, potentially leading to RCE via ZIP file extraction. The other vulnerability is found in the Sitecore PowerShell Extensions [8], permitting unrestricted file uploads through the /sitecore%20modules/Shell/PowerShell/UploadFile/PowerShellUploadFile2.aspx endpoint [2], which could enable attackers to upload malicious files to the server using the ServicesAPI user. Additionally, a critical path traversal vulnerability can be exploited in conjunction with the hardcoded credentials to achieve authenticated RCE. This exploit chain allows attackers to upload a ZIP archive containing a webshell, leading to full system takeover on unpatched versions of the CMS.
These vulnerabilities underscore critical flaws in Sitecore’s authentication practices and file handling mechanisms [8], posing significant risks to organizations utilizing the platform, including major companies such as United Airlines [1] [7], HSBC [6] [7], Procter & Gamble [1], Microsoft [1], L’Oréal [6] [7], and Fujitsu [1]. With over 22,000 Sitecore instances exposed online [2], the potential for widespread attacks is significant [2], as successful exploitation could result in data theft and operational disruption [2]. Organizations using Sitecore XP must prioritize patching and implementing robust security measures [3], including firewalls [3], intrusion detection systems [3], and regular security audits [3], to mitigate these risks [3] [4]. The report emphasizes the necessity of continuous security testing and prompt patching to effectively address such vulnerabilities, as many organizations may not apply patches promptly [4], leaving thousands of publicly exposed Sitecore instances vulnerable [4].
To further reduce the risk of mass compromise, organizations are urged to update to the latest patched version [4], rotate credentials for internal Sitecore service accounts [2], and audit server logs for suspicious activity [2]. A proactive approach to security [3], including educating employees about best practices [3], is vital for protecting sensitive data and maintaining customer trust in a digital landscape [3]. Organizations must remain vigilant and adaptable to safeguard their systems against emerging vulnerabilities [3], particularly in light of regulatory scrutiny related to data protection regulations like GDPR and HIPAA, which could lead to legal repercussions and reputational damage [3].
Conclusion
The vulnerabilities identified in Sitecore’s Experience Platform highlight significant security challenges that organizations must address to protect their systems and data. Immediate actions [3], such as applying patches, rotating credentials [2] [7], and conducting regular security audits, are essential to mitigate these risks [4]. Furthermore, organizations must adopt a proactive security posture, including employee education and continuous monitoring, to safeguard against future threats. Failure to address these vulnerabilities could result in severe legal and reputational consequences, especially under stringent data protection regulations.
References
[1] https://www.cyberswissguards.com/sitecore-cms-flaw-let-attackers-brute-force-b-for-backdoor/
[2] https://gbhackers.com/critical-vulnerabilities-in-sitecore/
[3] https://cloudindustryreview.com/critical-rce-vulnerability-in-sitecore-xp-due-to-hard-coded-b-password-in-enterprise-systems/
[4] https://cyberpress.org/vulnerabilities-in-sitecore-experience-platform/
[5] https://www.infosecurity-magazine.com/news/chained-flaws-cms-sitecore-rce/
[6] https://osintcorp.net/chained-flaws-in-enterprise-cms-provider-sitecore-could-allow-rce/
[7] https://thecyberwire.com/podcasts/daily-podcast/2331/transcript
[8] https://labs.watchtowr.com/is-b-for-backdoor-pre-auth-rce-chain-in-sitecore-experience-platform/
