CVE-2024-1459

What it actually does

Path traversal flaw permits remote unauthenticated attackers to append crafted sequences to HTTP requests, bypassing directory restrictions and reading privileged or sensitive files on the server.

Why it matters to the business

Attackers may obtain configuration files, credentials, or other restricted data, increasing risk of further compromise; the issue affects widely deployed Undertow-based servers with stable but non-zero exploit probability.

How an attack unfolds

An attacker identifies an Undertow-based application and appends traversal sequences such as ../ or encoded equivalents to an HTTP request URI, causing the server to serve files outside the intended web root.

How to fix it

Upgrade Undertow to version 2.3.18-1 or later on all affected Debian 13 deployments; apply vendor patches promptly given the 975 days since disclosure.

How to confirm the fix worked

Verify installed Undertow package version is 2.3.18-1 or newer; retest with known traversal payloads to confirm requests are now rejected or sanitized.

Typical attack path

1. Identify target application running vulnerable Undertow
2. Craft HTTP GET or similar request containing path traversal sequences
3. Submit request to access files outside the application directory
4. Exfiltrate or inspect retrieved sensitive file contents

How to detect it

Inspect web server and application logs for HTTP requests containing repeated dot-dot-slash or encoded traversal sequences; correlate with file access attempts to non-web directories.

• ..%2f
• ..%5c
• %2e%2e%2f
• GET .*\.\./

What your security team should do

• Immediately upgrade all Undertow instances to 2.3.18-1
• Review web server access logs for historical traversal patterns
• Enforce least-privilege file permissions on the host
• Implement WAF rules blocking common traversal sequences until patches are applied