CVE-2021-32682
Path Traversal in elFinder is an open-source file manager for web, written in JavaScript using jQuery UI
Executive Summary
CVE-2021-32682 is a critical severity vulnerability affecting appsec. It is classified as Path Traversal. Ensure your systems and dependencies are patched immediately to mitigate exposure risks.
Precogs AI Insight
"elFinder contains a command injection vulnerability due to improper sanitization of file names. Authenticated attackers upload a file with a crafted name to execute shell commands on the server during preview generation. Precogs Application Security Module tracks untrusted filenames directly to system shell execution."
What is this vulnerability?
CVE-2021-32682 is categorized as a critical Path Traversal flaw with a CVSS base score of 9.8. Based on our vulnerability intelligence, this issue occurs when the application fails to securely handle untrusted data boundaries.
elFinder is an open-source file manager for web, written in JavaScript using jQuery UI. Several vulnerabilities affect elFinder 2.1.58. These vulnerabilities can allow an attacker to execute arbitrary code and commands on the server hosting the elFinder PHP connector, even with minimal configuration. The issues were patched in version 2.1.59. As a workaround, ensure the connector is not exposed without authentication.
This architectural defect enables adversaries to bypass intended security controls, directly manipulating the application's execution state or data layer. Immediate strategic intervention is required.
Risk Assessment
| Metric | Value |
|---|---|
| CVSS Base Score | 9.8 (CRITICAL) |
| Vector String | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| Published | June 14, 2021 |
| Last Modified | November 21, 2024 |
| Related CWEs | CWE-22, CWE-78, CWE-918 |
Impact on Systems
✅ Data Exfiltration: Attackers can extract sensitive data from backend databases, configuration files, or internal services.
✅ Authentication Bypass: Exploiting this flaw may allow unauthorized access to protected resources and administrative interfaces.
✅ Lateral Movement: Once initial access is gained, attackers can pivot to internal systems and escalate privileges.
How to Fix and Mitigate CVE-2021-32682
- Apply Vendor Patches: Upgrade affected components to their latest, non-vulnerable versions immediately.
- Implement Input Validation: Ensure all user-supplied data is validated, sanitized, and type-checked before processing.
- Deploy Runtime Protection: Use Precogs continuous monitoring to detect exploitation attempts in real time.
- Audit Dependencies: Review and update all third-party libraries and transitive dependencies.
Defending with Precogs AI
elFinder contains a command injection vulnerability due to improper sanitization of file names. Authenticated attackers upload a file with a crafted name to execute shell commands on the server during preview generation. Precogs Application Security Module tracks untrusted filenames directly to system shell execution.
Use Precogs to continuously scan your codebase, binaries, APIs, and infrastructure for this vulnerability class and related attack patterns. Our AI-powered detection engine combines static analysis with threat intelligence to identify exploitable weaknesses before attackers do.
Vulnerability Code Signature
Attack Data Flow
| Stage | Detail |
|---|---|
| Source | User-supplied filename or path parameter |
| Vector | Path manipulation using dot-dot-slash (../) sequences |
| Sink | File system read/write operation |
| Impact | Unauthorized access to sensitive files (e.g., /etc/passwd), directory traversal |
Vulnerable Code Pattern
// ❌ VULNERABLE: Unvalidated path resolution
public File getFile(String filename) {
String basePath = "/var/www/uploads/";
// Taint sink: permits directory traversal via "../"
return new File(basePath + filename);
}
Secure Code Pattern
// ✅ SECURE: Canonical path validation
public File getFile(String filename) throws IOException {
File baseDir = new File("/var/www/uploads/").getCanonicalFile();
File requestedFile = new File(baseDir, filename).getCanonicalFile();
// Sanitized boundary check
if (!requestedFile.getPath().startsWith(baseDir.getPath())) {
throw new SecurityException("Path traversal attempt detected");
}
return requestedFile;
}
How Precogs Detects This
Precogs AI Analysis Engine utilizes semantic taint tracking to detect insecure path resolution sinks, ensuring file access is strictly bounded.\n