Sitecore XP Exploit Chain: Hardcoded Credentials Lead to Unauthenticated RCE

A critical vulnerability chain in Sitecore Experience Platform (XP) allows attackers to gain full server control starting with a hardcoded password (‘b’) for the default ServicesAPI account. This exploit chain, now cataloged by CISA as actively exploited, affects versions 10.1 through 10.4 of the enterprise CMS platform used by banks, airlines, and government agencies¹.

Executive Summary

The attack begins with authentication bypass using the hardcoded credentials, followed by one of two post-authentication remote code execution (RCE) paths. Security researchers at watchTowr Labs demonstrated how this combination could compromise a Sitecore server in under five minutes³. Sitecore has released patches in version 10.4.1, but many systems remain vulnerable due to the platform’s widespread enterprise use.

Initial Vector: Hardcoded password ‘b’ for sitecore\ServicesAPI account (CVE-2025-XXXXX)
Exploit Paths: ZIP slip via Upload2.aspx or direct file upload via PowerShell endpoint
Impact: Full server compromise with IIS privileges
Affected Versions: Sitecore XP 10.1-10.4 (fresh installations)
Mitigation: Upgrade to 10.4.1+, rotate all default credentials, restrict admin endpoints

Technical Breakdown

The exploit chain begins with the hardcoded credentials vulnerability, where the ServicesAPI account’s password was set to the single character ‘b’ in default installations. This account has administrative privileges and can be accessed through either the /sitecore/admin interface or the /sitecore/api/ssc/auth/login API endpoint².

Once authenticated, attackers can choose between two RCE methods. The first involves exploiting a path traversal vulnerability in the ZIP file upload functionality at /sitecore/shell/Applications/Dialogs/Upload/Upload2.aspx. By crafting a malicious ZIP with directory traversal sequences (e.g., /\\../webshell.aspx), attackers can write arbitrary files to the webroot⁴.

The second method leverages an unrestricted file upload endpoint at /sitecore%20modules/Shell/PowerShell/UploadFile/PowerShellUploadFile2.aspx. This allows direct upload of ASPX webshells without requiring ZIP archive manipulation. Both methods result in RCE with the privileges of the IIS application pool identity⁵.

Detection and Mitigation

Organizations should immediately audit their Sitecore installations for the following indicators:

Detection Method	Action
Check for existence of sitecore\ServicesAPI account	Disable or change password if found
Review IIS logs for access to /sitecore/admin or /sitecore/api/ssc/auth/login	Block external access to these endpoints
Monitor for unexpected file uploads to Upload2.aspx or PowerShellUploadFile2.aspx	Restrict upload functionality to authenticated, authorized users only

Sitecore’s official guidance recommends upgrading to version 10.4.1 or later, which removes the hardcoded credentials and implements proper file upload validation¹. For systems that cannot be immediately patched, implementing web application firewall rules to block suspicious upload patterns and restricting network access to administrative interfaces can reduce risk.

Historical Context and Industry Response

This isn’t Sitecore’s first authentication-related security issue. In 2024, researchers disclosed an order of operations bug (CVE-2024-46938) that allowed local file disclosure through the /-/speak/v1/bundles/bundle.js endpoint⁶. The current vulnerability chain represents a more severe threat due to its pre-authentication component and straightforward exploitation path.

“By default, recent Sitecore versions shipped with a user that had a hardcoded password of ‘b’. It’s 2025, and we can’t believe we still have to say this, but that’s very bad.”

— Benjamin Harris, CEO of watchTowr³

CISA added these vulnerabilities to its Known Exploited Vulnerabilities Catalog in March 2025, requiring federal agencies to patch affected systems by April 2025⁵. Private sector organizations, particularly in finance and healthcare, should treat this with equal urgency given the platform’s enterprise footprint.

Conclusion

The Sitecore XP vulnerability chain demonstrates how seemingly minor security oversights (hardcoded credentials) can combine with other weaknesses (insecure file uploads) to create critical risks. Organizations using Sitecore should prioritize patching and credential rotation, while security teams should monitor for exploitation attempts. The availability of public proof-of-concepts increases the likelihood of widespread attacks in the coming weeks.