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Prevent Upload of Attachment with High-Risk Type Files Control
Blocks upload of executable and high-risk file types (HTML, HTM, JS, EXE, and so on) as Attachments, Documents, or ContentVersion records, preventing stored XSS and malware distribution through Salesforce files.
Control Name
File Upload and Download Security (Prevent upload of attachment with high-risk type files)
Control Overview
Blocks upload of executable and high-risk file types (HTML, HTM, JS, EXE, and so on) as Attachments, Documents, or ContentVersion records, preventing stored XSS and malware distribution through Salesforce files.
Description
Org-wide setting in Setup>Security>File Upload and Download Security filters file extensions at upload time. Supports HTML upload blocking specifically for Experience Cloud portals and classic file storage.
Recommended Configuration
Security>File Upload and Download Security>Don't Allow HTML Uploads as Attachments or Document Records set to enable.
Security Impact
Eliminates primary vector for client-side attacks (XSS via HTML attachments, JavaScript execution in Content distributions); protects both Salesforce users and external recipients from malicious files.
Business Impact
Maintains legitimate document workflows while blocking only dangerous types. No user training required. Supports compliance requirements for secure file sharing.
Security Risk If Not Configured
Unrestricted upload of high-risk file types (HTML/JS) as attachments or document records enables persistent XSS and malware persistence within Salesforce.
Threat Scenarios
Significant risk of malware and malicious executable uploads, creating endpoint compromise risk; attackers upload HTML/JS files disguised as documents that execute when previewed/downloaded, compromising user browsers/sessions.
Estimated CVSS Score Range
High (7.0–8.9).
Risk Impact Considerations
External/Community users amplify the risk; legitimate HTML use cases (invoices, reports) require ContentVersion or alternative storage; antivirus scanning recommended as defense-in-depth.
Higher Risk When
Experience Cloud and Community portals enabled, external file sharing active, custom file upload components, or high executive/customer file upload volume.
Low Risk When
Internal users only, strict Content security policies, Files disabled, or comprehensive antivirus/EDR deployed on endpoints.
Business and Integration Considerations
Test legitimate file types post-configuration; combine with CSP headers and Lightning Locker for comprehensive client-side protection.
Security Health Review Guidance
Strongly recommended.
Who Is Impacted
All users with file upload permissions, Experience Cloud portal users, security teams monitoring upload patterns, compliance officers verifying secure file handling.
