CVE-2021-3619 in Velociraptor
Summary
by MITRE • 07/23/2021
Rapid7 Velociraptor 0.5.9 and prior is vulnerable to a post-authentication persistent cross-site scripting (XSS) issue, where an authenticated user could abuse MIME filetype sniffing to embed executable code on a malicious upload. This issue was fixed in version 0.6.0. Note that login rights to Velociraptor is nearly always reserved for trusted and verified users with IT security backgrounds.
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Analysis
by VulDB Data Team • 07/27/2021
The vulnerability CVE-2021-3619 affects Rapid7 Velociraptor versions 0.5.9 and earlier, representing a post-authentication persistent cross-site scripting flaw that demonstrates a critical weakness in the application's file upload validation mechanisms. This vulnerability specifically exploits the application's MIME type sniffing behavior during file uploads, allowing authenticated users to manipulate file type detection and subsequently inject malicious code into the system. The issue resides in how Velociraptor processes uploaded files, particularly when the system attempts to determine file types through content inspection rather than relying solely on file extensions. The vulnerability is classified under CWE-79, which specifically addresses cross-site scripting flaws, and represents a persistent XSS vulnerability that can maintain its impact across multiple user sessions. The attack vector requires an authenticated user context, which aligns with the ATT&CK technique T1078.004 for valid accounts, though the restricted access requirements make this vulnerability less likely to be exploited by casual attackers.
The technical exploitation of this vulnerability involves leveraging the MIME type sniffing functionality to bypass normal file validation procedures. When a user uploads a file, Velociraptor's system performs content analysis to determine the actual file type rather than relying exclusively on the file extension. An attacker with valid credentials can craft a malicious file that appears to be one type during upload but is actually another type that triggers the XSS payload. This technique exploits the trust placed in the application's automatic file type detection mechanisms and demonstrates a failure in proper input validation and sanitization. The vulnerability's persistence stems from the fact that once the malicious file is uploaded and processed, the XSS payload remains embedded in the system's data storage or display mechanisms, allowing it to execute whenever the affected page is accessed by other users. The flaw essentially creates a sandbox escape scenario where legitimate file upload functionality becomes a vector for malicious code execution.
The operational impact of CVE-2021-3619 is significant within enterprise security environments where Velociraptor is deployed for incident response and digital forensics activities. While the vulnerability requires authentication and typically only affects trusted users, the implications extend beyond simple XSS execution to potentially compromise the entire incident response infrastructure. Attackers could use this vulnerability to escalate privileges, steal session tokens, or gain access to sensitive forensic data and evidence. The vulnerability's exploitation would be particularly concerning in environments where Velociraptor is used to analyze compromised systems, as it could allow attackers to manipulate forensic data or even inject malicious payloads into the investigation process itself. Organizations using Velociraptor for security operations would face potential data integrity issues, as the persistent nature of the XSS flaw could allow attackers to maintain access to the system even after initial exploitation. The vulnerability's remediation requires updating to version 0.6.0 or later, which implements proper MIME type validation and sanitization mechanisms.
Mitigation strategies for CVE-2021-3619 should focus on immediate version upgrades to 0.6.0 or later, as this represents the most effective solution to address the underlying vulnerability. Organizations should also implement additional monitoring and logging around file upload activities, particularly focusing on unusual MIME type detections or file content modifications. Network segmentation and privileged access controls should be reinforced to limit potential exploitation even if the vulnerability is somehow bypassed. Security teams should conduct thorough vulnerability assessments of all Velociraptor deployments to ensure proper patching across all environments. The vulnerability's classification as a post-authentication issue means that strong access control measures, including multi-factor authentication and regular credential rotation, should be implemented to minimize the attack surface. Regular security testing of the application's file handling mechanisms should be conducted to identify similar vulnerabilities in other security tools that might be similarly affected by MIME type sniffing behaviors. The fix implemented in version 0.6.0 addresses the root cause by strengthening the file validation process and ensuring that MIME type detection does not introduce XSS vulnerabilities into the system's processing pipeline.