CVE-2024-38534 – CVE-2024-38534 is a denial-of-service vulnerabi... (How to Fix)

Q: What is the severity of CVE-2024-38534?

CVE-2024-38534 has a CVSS score of 7.5 (HIGH). CVE-2024-38534 is a denial-of-service vulnerability in Suricata where specially crafted Modbus traffic can cause unlimited resource accumulation within a flow, potentially leading to system resource exhaustion. This affects organizations using Suricata for network security monitoring, intrusion detection, or prevention. The vulnerability is present in Suricata versions before 7.0.6.

📋 TL;DR

CVE-2024-38534 is a denial-of-service vulnerability in Suricata where specially crafted Modbus traffic can cause unlimited resource accumulation within a flow, potentially leading to system resource exhaustion. This affects organizations using Suricata for network security monitoring, intrusion detection, or prevention. The vulnerability is present in Suricata versions before 7.0.6.

💻 Affected Systems

Products:

Suricata

Versions: All versions before 7.0.6

Operating Systems: All platforms running Suricata

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects deployments processing Modbus traffic; default configurations are vulnerable if Modbus inspection is enabled.

📦 What is this software?

Suricata by Oisf

View all CVEs affecting Suricata →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete denial of service where Suricata consumes all available system resources (CPU, memory), causing the service to crash and potentially affecting the entire host system's stability.

🟠

Likely Case

Degraded performance or service disruption of Suricata, reducing network security monitoring capabilities and potentially allowing malicious traffic to bypass detection.

🟢

If Mitigated

Limited impact with proper stream.reassembly.depth configuration, though some performance degradation may still occur under attack.

🌐 Internet-Facing: MEDIUM - Suricata typically monitors internal traffic but may be exposed to internet traffic in perimeter deployments; Modbus traffic is usually internal but could be tunneled.

🏢 Internal Only: HIGH - Most Suricata deployments monitor internal networks where Modbus traffic is common in industrial control systems and SCADA environments.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW - Requires sending specially crafted Modbus packets to monitored network segments.

Exploitation requires network access to send Modbus traffic to Suricata-monitored segments; no authentication needed.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 7.0.6

Vendor Advisory: https://github.com/OISF/suricata/security/advisories/GHSA-59qg-h357-69fq

Restart Required: Yes

Instructions:

1. Download Suricata 7.0.6 from official sources. 2. Stop Suricata service. 3. Backup current configuration. 4. Install/upgrade to 7.0.6. 5. Restart Suricata service. 6. Verify version and functionality.

🔧 Temporary Workarounds

Limit stream reassembly depth

all

Configure stream.reassembly.depth to limit resource accumulation in flows

Edit suricata.yaml and set: stream:
  reassembly:
    depth: 1048576  # 1MB limit

Disable Modbus protocol inspection

all

Temporarily disable Modbus protocol parsing if not needed

Edit suricata.yaml and modify app-layer protocols: app-layer:
  protocols:
    modbus:
      enabled: no

🧯 If You Can't Patch

Implement network segmentation to isolate Modbus traffic from Suricata monitoring
Deploy rate limiting or traffic filtering for Modbus protocols at network boundaries

🔍 How to Verify

Check if Vulnerable:

Check Suricata version: suricata --build-info | grep 'Version' and compare to 7.0.6

Check Version:

suricata --build-info | grep 'Version:'

Verify Fix Applied:

Verify version is 7.0.6 or later and test with sample Modbus traffic to ensure no resource exhaustion

📡 Detection & Monitoring

Log Indicators:

High memory/CPU usage alerts from Suricata
Suricata process crashes or restarts
Unusual Modbus traffic patterns in Suricata logs

Network Indicators:

Abnormal volumes of Modbus traffic
Malformed Modbus packets
Traffic patterns designed to create long-lived flows

SIEM Query:

source="suricata" ("out of memory" OR "resource exhaustion" OR "process crash") OR (protocol="modbus" AND (packet_size>normal OR flow_duration>threshold))

📊 Metadata

CVE ID: CVE-2024-38534

CVSS v3 Score: 7.5 (HIGH)

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

CWE: CWE-770

Published: July 11, 2024

Last Updated: November 21, 2024

🔗 References

https://github.com/OISF/suricata/commit/a753cdbe84caee3b66d0bf49b2712d29a50d67ae Patch
https://github.com/OISF/suricata/security/advisories/GHSA-59qg-h357-69fq Vendor Advisory
https://redmine.openinfosecfoundation.org/issues/6987 Issue Tracking
https://redmine.openinfosecfoundation.org/issues/6988 Issue Tracking
https://github.com/OISF/suricata/commit/a753cdbe84caee3b66d0bf49b2712d29a50d67ae Patch
https://github.com/OISF/suricata/security/advisories/GHSA-59qg-h357-69fq Vendor Advisory
https://redmine.openinfosecfoundation.org/issues/6987 Issue Tracking
https://redmine.openinfosecfoundation.org/issues/6988 Issue Tracking

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