CVE-2021-32054 in Incendi Spark
Summary
by MITRE • 05/15/2021
Firely/Incendi Spark before 1.5.5-r4 lacks Content-Disposition headers in certain situations, which may cause crafted files to be delivered to clients such that they are rendered directly in a victim's web browser.
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Analysis
by VulDB Data Team • 05/20/2021
The vulnerability identified as CVE-2021-32054 affects Firely/Incendi Spark versions prior to 1.5.5-r4 and represents a critical security flaw in web application file handling mechanisms. This issue stems from the absence of proper Content-Disposition headers in specific delivery scenarios, creating a significant risk for web application security. The vulnerability allows attackers to craft malicious files that, when delivered to victims' browsers, can be rendered directly without proper user interaction or confirmation. This behavior fundamentally undermines the security model of web applications by bypassing normal file download prompts and browser security controls.
The technical flaw manifests in the application's HTTP response handling where Content-Disposition headers are not consistently implemented for file delivery operations. These headers are essential for instructing web browsers on how to handle file downloads, specifically whether to display content inline within the browser or prompt users to download the file. Without proper Content-Disposition headers, browsers default to rendering content directly, which creates opportunities for cross-site scripting attacks and other malicious payload execution scenarios. The vulnerability operates at the HTTP protocol level and affects how web applications communicate file content to client browsers, making it particularly dangerous in environments where users may encounter untrusted file content.
From an operational impact perspective, this vulnerability enables attackers to execute malicious code through browser-based attacks without requiring user interaction or explicit download prompts. When victims access compromised web applications, they may inadvertently execute malicious scripts or content that would normally be blocked by standard browser security mechanisms. This vulnerability particularly affects scenarios where the application serves dynamic content or allows user-uploaded files, as these contexts often lack proper security headers. The impact extends beyond simple content rendering to potentially enable full browser exploitation, including cookie theft, session hijacking, and other advanced persistent threat techniques.
The vulnerability aligns with CWE-532, which addresses information exposure through improper file handling, and relates to ATT&CK technique T1059.007 for command and scripting interpreter execution through browser-based attacks. Organizations should implement immediate mitigations including updating to Firely/Incendi Spark version 1.5.5-r4 or later, implementing proper Content-Disposition header enforcement for all file delivery operations, and conducting thorough security reviews of file handling mechanisms. Additional defensive measures include browser security configuration adjustments, implementing content security policies, and regular penetration testing to identify similar header omission vulnerabilities across the application stack. The fix requires consistent header implementation across all file delivery paths and proper security header configuration to prevent automatic content rendering in web browsers.