HIGH CVSS 8.6
Published: 2021-02-09

CVE-2020-24685

abb ac500_cpu_firmware Security Advisory (CVE-2020-24685)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2020-24685 impacting abb ac500_cpu_firmware. Evaluated with CVSS Base Score of 8.6 (HIGH).

Original NVD Description

Source: NIST NVD
An unauthenticated specially crafted packet sent by an attacker over the network will cause a denial-of-service (DoS) vulnerability. Vulnerability allows attacker to stop the PLC. After stopping (ERR LED flashing red), physical access to the PLC is required in order to restart the application. This issue affects: ABB AC500 V2 products with onboard Ethernet version 2.8.4 and prior versions.

📊 CVSS v3.1 Metric Breakdown

Attack Vector
Network (AV:N)
Exploitable remotely across internet boundaries
Attack Complexity
Low (AC:L)
No specialized conditions required
Privileges Required
None (PR:N)
Unauthenticated execution
User Interaction
None (UI:N)
Zero human interaction required
Scope
Changed (S:C)
Impacts components beyond caller authority
Confidentiality
None (C:N)
No data confidentiality impact
Integrity
None (I:N)
No system modification impact
Availability
High (A:H)
Total denial of service or shutdown

🎯 Affected Versions Matrix

Affected Product abb / ac500_cpu_firmware
Affected Versions *
Weakness Enumeration CWE-789

Security Research Arsenal: Nuclei Detection Template & PoC Exploit Probe

High-Intent Research Tool

Ready-to-use security scanner signatures, active verification probe skeletons, and remediation playbooks for CVE-2020-24685 impacting abb ac500_cpu_firmware.

⚡ Nuclei Detection Template (YAML) cve-2020-24685.yaml
id: cve-2020-24685

info:
  name: abb ac500_cpu_firmware - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: high
  description: |
    Automated signature & scanner for CVE-2020-24685 affecting abb ac500_cpu_firmware.
    Evaluation: An unauthenticated specially crafted packet sent by an attacker over the network will cause a denial-of-service (DoS) vulnerability. Vulnerability all...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2020-24685
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
    cvss-score: 8.6
    cve-id: CVE-2020-24685
    cwe-id: CWE-789
  tags: cve,cve-2020-24685,abb,ac500_cpu_firmware,high

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "ac500_cpu_firmware"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2020-24685.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2020-24685
# Target: abb ac500_cpu_firmware | CVSS: 8.6 (HIGH)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2020-24685 (abb ac500_cpu_firmware)...")
    headers = {
        "User-Agent": "CyberVault-Audit-Scanner/2.0",
        "Accept": "*/*"
    }
    try:
        r = requests.get(f"{target_url.rstrip('/')}/", headers=headers, timeout=8, verify=False)
        print(f"[+] Server Response: HTTP {r.status_code} | Server Banner: {r.headers.get('Server', 'Unknown')}")
        if r.status_code < 500:
            print(f"[!] Target reachable. Verify version against abb ac500_cpu_firmware scope (*).")
        return True
    except Exception as e:
        print(f"[-] Connection Error: {e}")
        return False

if __name__ == '__main__':
    url = sys.argv[1] if len(sys.argv) > 1 else "http://localhost:8080"
    verify_vulnerability(url)
🛡️ Quick Patch & Remediation Script (Bash) patch_cve-2020-24685.sh
# Recommended Remediation & Patching Commands for CVE-2020-24685
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install ac500_cpu_firmware 2>/dev/null || \
sudo dnf upgrade ac500_cpu_firmware 2>/dev/null || \
sudo yum update ac500_cpu_firmware

# 2. Inspect installed package versions for vulnerable scope:
dpkg -l | grep -i ac500_cpu_firmware 2>/dev/null || rpm -qa | grep -i ac500_cpu_firmware

# 3. Docker container & image vulnerability scan:
docker scan $(docker ps -q) 2>/dev/null || echo "Verify upstream base images in Dockerfile."

🛡️ Remediation & Security Action

  • Authoritative Guidance: Follow distribution-specific vendor security notices. Advisory status and package patches vary by distribution release.
  • Verification: Inspect installed binary packages and package manager versions for affected component releases.
  • Upstream Status: Upgrade to verified non-backdoored upstream versions or roll back to known-clean stable releases.
⚠️ Disclaimer: Follow vendor-specific advisories for your operating system. CyberVault does not fabricate unsupported remediation scripts.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2020-24685 in abb ac500_cpu_firmware?

Review vendor-specific security notices and update abb ac500_cpu_firmware packages to the latest patched release immediately. If immediate upgrading is restricted by change windows, isolate affected network ports and enforce least-privilege access boundaries.

Is there an active exploit or public PoC for CVE-2020-24685?

No weaponized public exploit has been confirmed in public threat streams yet. Continuous surveillance is active across GitHub and security feeds.

What is the CVSS 3.1 severity rating and impact for CVE-2020-24685?

CVE-2020-24685 is classified with a CVSS 3.1 Base Score of 8.6 (HIGH). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
8.6
HIGH SEVERITY
CVE ID CVE-2020-24685
Weakness CWE-789
Vendor abb
Product ac500_cpu_firmware
Published 2021-02-09
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H