CVE-2023-0056

Q: What is the severity of CVE-2023-0056?

CVE-2023-0056 has a CVSS score of 6.5 (MEDIUM). An uncontrolled resource consumption vulnerability in HAProxy could allow an authenticated remote attacker to crash the service by running a specially crafted malicious server in an OpenShift cluster. This primarily affects availability of HAProxy instances in OpenShift environments. Organizations using vulnerable HAProxy versions in OpenShift clusters are affected.

6.5 MEDIUM

Denial of Service

📋 TL;DR

An uncontrolled resource consumption vulnerability in HAProxy could allow an authenticated remote attacker to crash the service by running a specially crafted malicious server in an OpenShift cluster. This primarily affects availability of HAProxy instances in OpenShift environments. Organizations using vulnerable HAProxy versions in OpenShift clusters are affected.

💻 Affected Systems

Products:

HAProxy
OpenShift

Versions: Specific HAProxy versions used in OpenShift clusters (check Red Hat advisory for exact versions)

Operating Systems: Linux distributions running OpenShift

Default Config Vulnerable: ✅ No

Notes: Requires OpenShift cluster environment with HAProxy and authenticated attacker access to deploy malicious server.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete service outage of HAProxy, disrupting traffic routing and load balancing for applications in the OpenShift cluster.

🟠

Likely Case

Service crashes leading to temporary unavailability until HAProxy restarts, potentially causing application downtime.

🟢

If Mitigated

Minimal impact with proper monitoring and automated restart mechanisms in place.

🌐 Internet-Facing: MEDIUM - Requires authenticated access and specific OpenShift cluster configuration.

🏢 Internal Only: MEDIUM - Same requirements as internet-facing, but internal attackers could exploit if they have cluster access.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires authenticated access to OpenShift cluster and ability to deploy malicious server components.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Check Red Hat advisory for specific patched versions

Vendor Advisory: https://access.redhat.com/security/cve/CVE-2023-0056

Restart Required: Yes

Instructions:

1. Check Red Hat advisory for patched HAProxy versions. 2. Update HAProxy in OpenShift cluster. 3. Restart HAProxy services. 4. Verify functionality.

🔧 Temporary Workarounds

Restrict Cluster Access

all

Limit authenticated access to OpenShift cluster to trusted users only.

Implement Resource Limits

linux

Configure resource limits for HAProxy containers to mitigate resource exhaustion.

oc set resources deployment/haproxy --limits=cpu=2,memory=2Gi

🧯 If You Can't Patch

Implement strict access controls to OpenShift cluster
Monitor HAProxy resource usage and set up alerts for abnormal consumption

🔍 How to Verify

Check if Vulnerable:

Check HAProxy version in OpenShift cluster and compare with Red Hat advisory.

Check Version:

haproxy -v

Verify Fix Applied:

Verify HAProxy version is updated to patched version and service is running normally.

📡 Detection & Monitoring

Log Indicators:

HAProxy service crashes
Resource exhaustion warnings
Abnormal memory/CPU usage patterns

Network Indicators:

Sudden loss of HAProxy service
Connection failures to backend services

SIEM Query:

source="haproxy.log" AND ("out of memory" OR "segmentation fault" OR "crash")

📊 Metadata

CVE ID: CVE-2023-0056

CVSS v3 Score: 6.5 (MEDIUM)

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

CWE: CWE-400

Published: March 23, 2023

Last Updated: February 25, 2025

🔗 References

https://access.redhat.com/security/cve/CVE-2023-0056 Vendor Advisory
https://access.redhat.com/security/cve/CVE-2023-0056 Vendor Advisory

📋 TL;DR

💻 Affected Systems

📦 What is this software?

Ceph Storage by Redhat

Extra Packages For Enterprise Linux by Fedoraproject

Fedora by Fedoraproject

Fedora by Fedoraproject

Haproxy by Haproxy

Openshift Container Platform by Redhat

Openshift Container Platform by Redhat

Openshift Container Platform by Redhat

Openshift Container Platform by Redhat

Openshift Container Platform by Redhat

Openshift Container Platform by Redhat

Openshift Container Platform by Redhat

Openshift Container Platform For Ibm Linuxone by Redhat

Openshift Container Platform For Ibm Linuxone by Redhat

Openshift Container Platform For Ibm Linuxone by Redhat

Openshift Container Platform For Ibm Linuxone by Redhat

Openshift Container Platform For Power by Redhat

Openshift Container Platform For Power by Redhat

Openshift Container Platform For Power by Redhat

Openshift Container Platform For Power by Redhat

Openshift Container Platform Ibm Z Systems by Redhat

Openshift Container Platform Ibm Z Systems by Redhat

Openshift Container Platform Ibm Z Systems by Redhat

Openshift Container Platform Ibm Z Systems by Redhat

Software Collections by Redhat

⚠️ Risk & Real-World Impact

Worst Case

Likely Case

If Mitigated

🎯 Exploit Status

🛠️ Fix & Mitigation

✅ Official Fix

Instructions:

🔧 Temporary Workarounds

Restrict Cluster Access

Implement Resource Limits

🧯 If You Can't Patch

🔍 How to Verify

Check if Vulnerable:

Check Version:

Verify Fix Applied:

📡 Detection & Monitoring

Log Indicators:

Network Indicators:

SIEM Query:

📊 Metadata

🔗 References

📤 Share & Export

🔗 Related Vulnerabilities