CVE-2024-3653 – This CVE describes a vulnerability in Undertow'... (How to Fix)

Q: What is the severity of CVE-2024-3653?

CVE-2024-3653 has a CVSS score of 5.3 (MEDIUM). This CVE describes a vulnerability in Undertow's learning-push handler when enabled with default configuration. Attackers can exploit this via HTTP requests to cause resource exhaustion or denial of service. Only systems with the learning-push handler explicitly enabled are affected.

📋 TL;DR

This CVE describes a vulnerability in Undertow's learning-push handler when enabled with default configuration. Attackers can exploit this via HTTP requests to cause resource exhaustion or denial of service. Only systems with the learning-push handler explicitly enabled are affected.

💻 Affected Systems

Products:

Undertow

Versions: Specific versions not specified in CVE, check Red Hat advisories for affected versions

Operating Systems: Any OS running vulnerable Undertow versions

Default Config Vulnerable: ✅ No

Notes: Only vulnerable when learning-push handler is explicitly enabled in server configuration

⚠️ Manual Verification Required

This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.

Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).

🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.

Recommended Actions:

Review the CVE details at NVD
Check vendor security advisories for your specific version
Test if the vulnerability is exploitable in your environment
Consider updating to the latest version as a precaution

⚠️ Risk & Real-World Impact

🔴

Worst Case

Resource exhaustion leading to denial of service, potentially disrupting web server availability

🟠

Likely Case

Degraded server performance or temporary unavailability under targeted attack

🟢

If Mitigated

No impact if learning-push handler is disabled or properly configured

🌐 Internet-Facing: MEDIUM - Attackers can exploit via HTTP requests, but requires specific configuration

🏢 Internal Only: LOW - Requires internal attacker with network access to vulnerable server

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW

Exploitation requires HTTP access to server and learning-push handler enabled

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Check Red Hat advisories for specific patched versions

Vendor Advisory: https://access.redhat.com/errata/RHSA-2024:4392

Restart Required: Yes

Instructions:

1. Update Undertow to patched version from Red Hat repositories. 2. Restart affected services. 3. Verify configuration changes if needed.

🔧 Temporary Workarounds

Disable learning-push handler

all

Ensure learning-push handler is disabled in server configuration

Check undertow configuration files for 'learning-push' handler settings

Configure maxAge parameter

all

Set maxAge to a positive value in learning-push handler configuration

Configure maxAge > 0 in undertow server configuration

🧯 If You Can't Patch

Disable learning-push handler in server configuration
Implement network controls to restrict HTTP access to vulnerable servers

🔍 How to Verify

Check if Vulnerable:

Check if learning-push handler is enabled in undertow configuration with maxAge = -1 or unset

Check Version:

Check application server documentation for version command

Verify Fix Applied:

Verify undertow version is patched and learning-push handler is disabled or maxAge is configured > 0

📡 Detection & Monitoring

Log Indicators:

Unusual HTTP request patterns to learning-push endpoints
Resource exhaustion warnings in server logs

Network Indicators:

Multiple HTTP requests to learning-push handler endpoints
Unusual traffic patterns to vulnerable server

SIEM Query:

Search for HTTP requests containing 'learning-push' in URI path or unusual resource consumption patterns

📊 Metadata

CVE ID: CVE-2024-3653

CVSS v3 Score: 5.3 (MEDIUM)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CWE: CWE-401

Published: July 8, 2024

Last Updated: November 21, 2024

🔗 References

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