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Introduction:
The cybersecurity industry is obsessed with zero‑day exploits and Hollywood‑style breaches, yet the vast majority of successful attacks leverage vulnerabilities that have had patches available for years. As highlighted by a recent LinkedIn discussion, the real crisis is cultural: organizations routinely ignore known CVEs from 2020 and earlier, leaving devices exposed and easily discoverable via Shodan. This article moves beyond the “Mythos” hype and provides actionable, hands‑on techniques to identify, verify, and remediate these neglected vulnerabilities using real commands and best practices.
Learning Objectives:
- Use Shodan and manual scanning to discover legacy CVEs on your public‑facing assets.
- Distinguish between false positives from automated scanners and genuine risks with manual verification.
- Implement sustainable patching, virtual patching, and cloud hardening strategies for unpatched 2020‑era vulnerabilities.
1. Shodan: Your Window into Forgotten Vulnerabilities
Many organizations are shocked to learn how many of their devices still expose services vulnerable to CVEs from 2020 or earlier. Shodan (https://www.shodan.io) is the search engine for internet‑connected devices, and a quick query can reveal exactly what attackers see.
Step‑by‑step guide to using Shodan for legacy CVE discovery:
- Create a Shodan account (free tier allows limited searches, paid unlocks full results).
- Install the Shodan CLI on your Linux or Windows machine (Python required):
pip install shodan shodan init YOUR_API_KEY
- Search for known vulnerable services – for example, find devices with unpatched Apache Log4j (CVE‑2021‑44228) or outdated OpenSSL:
shodan search "http.title: 'Apache Tomcat' 2020" shodan search "product: 'OpenSSL' version:1.0.2"
4. Filter by country, port, or CVE:
shodan search --fields ip_str,port,cve 'cve:CVE-2020-1472' ZeroLogon
5. Download results for offline analysis:
shodan download legacy_scan --limit 1000 'cve:CVE-2020-0601' shodan parse --fields ip_str,port,cve legacy_scan.json.gz
6. Cross‑reference with your own IP ranges using the `net:` filter:
shodan search net:YOUR_PUBLIC_CIDR/24
This process immediately highlights which of your assets still carry old, unpatched vulnerabilities – often the same ones attackers scan for daily.
2. Manual Verification: Cutting Through False Positives
Commercial scanners like Tenable, Qualys, and Rapid7 are excellent but notorious for false positives. The LinkedIn commenter’s advice to “do something more manual” is critical. Manual verification saves time and reduces alert fatigue.
Step‑by‑step guide to manual validation:
1. Confirm the service version using banner grabbing:
nc -nv TARGET_IP 443
Or use `nmap` with version detection:
nmap -sV --script banner -p 80,443,22 TARGET_IP
2. Search for the exact CVE in public databases (NVD, CVE Details) to understand affected versions.
3. Use a lightweight PoC scanner like `nuclei` (https://github.com/projectdiscovery/nuclei):
nuclei -u https://TARGET_IP -t cves/2020/ -severity high,critical
This runs only CVE‑2020 templates, avoiding the noise of newer detections.
4. For Windows systems, query the installed patches via PowerShell to see if a CVE has been fixed:
Get-HotFix | Where-Object { $<em>.InstalledOn -lt (Get-Date).AddYears(-3) }
Get-WmiObject -Class Win32_QuickFixEngineering | Where-Object { $</em>.HotFixID -like "KB4" }
5. For Linux, check package versions against known vulnerable ones:
Debian/Ubuntu dpkg -l | grep -E "openssl|apache2|nginx" RHEL/CentOS rpm -qa --last | head -20 Check if a specific CVE is patched (using OVAL) oval eval --definition CVE-2020-1234 --results results.xml
If the version reported matches the vulnerable range and no compensating control is in place, treat it as a true positive – regardless of what the commercial scanner says.
- Patch Management at Scale: Windows & Linux Commands
Once you have a verified list of missing patches, you need to deploy them efficiently. Here are the essential commands for manual and automated patching.
Windows (Command Line & PowerShell):
List missing updates using Windows Update API Get-WindowsUpdate -Install -AcceptAll -AutoReboot Install specific KB (e.g., for CVE-2020-1472) wusa.exe c:\temp\KB4565351.msu /quiet /norestart Query update history Get-HotFix | Sort-Object InstalledOn -Descending | Select-Object -First 20 For offline servers, use DISM dism /online /get-packages | findstr "Package_for_KB" dism /online /add-package /packagepath:C:\updates\KB4565351.cab
Linux (apt, yum, zypper):
Debian/Ubuntu: list pending security updates apt list --upgradable | grep security sudo unattended-upgrades --dry-run Apply only security updates sudo apt-get update && sudo apt-get upgrade -s RHEL/CentOS: list relevant errata yum updateinfo list security all yum update --security -y OpenSUSE: apply patches for specific CVE zypper patch --cve=CVE-2020-1578 Alpine Linux apk upgrade --available
Automation with Ansible (playbook for cross‑platform patching):
- name: Apply critical security patches hosts: all tasks: - name: Windows - install all critical updates win_updates: category_names: SecurityUpdates state: installed when: ansible_os_family == "Windows" <ul> <li>name: Linux - upgrade security packages apt: upgrade: safe update_cache: yes only_upgrade: yes when: ansible_os_family == "Debian"
Schedule these commands via cron or Task Scheduler to ensure that patches for 2020 CVEs are never left behind again.
4. Virtual Patching: A Double‑Edged Sword
When a business cannot reboot a legacy system, virtual patching (using a WAF or intrusion prevention system) is often chosen as a compensating control. However, as the LinkedIn anecdote shows, this approach frequently fails. Use it only as a temporary measure.
Step‑by‑step to implement virtual patching for CVE‑2020‑0601 (Windows CryptoAPI spoofing) using ModSecurity:
- Install ModSecurity (on a reverse proxy like Nginx or Apache):
sudo apt install libapache2-mod-security2 sudo a2enmod security2
- Download or write a rule that blocks exploitation attempts. For example, a rule that checks for malformed certificate signatures:
SecRule REQUEST_HEADERS:Host "..evil.com" "id:1001,deny,status:403,msg:'Suspected CVE-2020-0601 exploitation'"
3. Enable the rule in the configuration:
sudo nano /etc/modsecurity/custom_rules.conf sudo systemctl restart apache2
4. Monitor logs to ensure the virtual patch is actually blocking attacks (and not legitimate traffic):
tail -f /var/log/modsec_audit.log
Caution: Virtual patching does not fix the underlying vulnerability. Attackers may bypass the WAF via encoding, fragmentation, or by attacking another path. Always plan for a real patch within a defined SLA (e.g., 90 days). Use virtual patching only as a bridge.
5. Cloud Hardening for Legacy Workloads
Cloud environments often accumulate unpatched virtual machines and containers from 2020. Major providers offer native tools to detect and remediate these CVEs automatically.
AWS:
- Use Amazon Inspector to scan EC2 instances for CVEs older than 3 years.
aws inspector2 create-findings-report --filter '{"cveId":["CVE-2020-"]}' - Automate patching with AWS Systems Manager Patch Manager:
aws ssm send-command --document-name "AWS-RunPatchBaseline" --instance-ids i-1234567890 --parameters '{"Operation":["ScanAndInstall"]}'
Azure:
- Enable Azure Update Management (Automation Account) and schedule weekly assessments.
- Use Azure Policy to enforce that VMs have latest security updates:
Get-AzVM | ForEach-Object { Invoke-AzVmAssessment -ResourceGroupName $<em>.ResourceGroupName -Name $</em>.Name }
GCP:
- Deploy OS Patch Management via GCP OS Config:
gcloud compute os-config patch-jobs execute --instance-filter=all --duration=4h --reboot-config=REBOOT_ALWAYS
- For containers, scan images with Google Container Analysis and block deployments with old CVEs:
gcloud artifacts docker images scan IMAGE_URL --location=us
In all clouds, set up automated remediation for any CVE with a CVSS score > 7.0 that is older than 365 days. This directly addresses the cultural problem described in the original post.
6. Building a Sustainable Vulnerability Mitigation Culture
The final step is moving from reactive scanning to a proactive culture. Use this five‑stage workflow to ensure that 2020 CVEs never linger again.
Stage 1: Asset Inventory – Run weekly Shodan and internal scans. Export results to a CSV:
shodan download inventory --limit 5000 'org:"Your Company"'
Stage 2: Risk Scoring – Weight CVEs by age (older = higher risk) and exploit availability (check CISA KEV catalog):
curl https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json | jq '.vulnerabilities[] | select(.dateAdded | contains("2020"))'
Stage 3: SLA Assignment – Define that any CVE > 2 years old must be patched within 7 days. Use a ticketing system (Jira, ServiceNow) with automation:
Example: create Jira ticket via CLI
curl -u user:token -X POST -H "Content-Type: application/json" -d '{"fields":{"project":{"key":"SEC"},"summary":"Patch CVE-2020-1234","description":"Found on asset X"}}' https://your-domain.atlassian.net/rest/api/2/issue
Stage 4: Remediation Validation – After patching, re‑run the same `nmap` or `nuclei` command to confirm the vulnerability is gone.
Stage 5: Reporting – Produce a monthly “legacy CVE” dashboard. Include metrics like “number of CVEs older than 2 years” and “average patch time”.
Embed this workflow into your change management process. As the LinkedIn commenter wisely said, “mitigar lo que hace bastante rato sabemos que existe es mucho más efectivo.”
What Undercode Say:
- Cultural inertia is the real vulnerability – organizations obsess over zero‑days while leaving 2020 CVEs unpatched for years, creating easy entry points for attackers.
- Automated scanners are not enough – false positives from tools like Tenable and Qualys lead to alert fatigue; manual verification with Shodan, nuclei, and native OS commands is essential to prioritize real risks.
- Virtual patching is a temporary crutch – relying on WAF rules or IPS without a roadmap to permanent fixes results in the same failures seen in the LinkedIn anecdote (the “virtual patching” that eventually collapsed).
Prediction:
Within the next 18 months, we will see a major breach exploiting a CVE from 2020 or earlier – not because the vulnerability was unknown, but because the victim had ignored it for years. Regulatory bodies (e.g., SEC, EU CSIRT) will begin fining organizations for failing to patch publicly known, exploit‑available CVEs older than two years. This will force a shift from chasing “Mythos” zero‑days to implementing mandatory, verifiable patch SLAs. Automated remediation pipelines (e.g., GitHub Dependabot for infrastructure, AWS Patch Manager) will become the norm, and cybersecurity professionals who cannot manually verify and patch legacy CVEs will be left behind. The cultural problem described in the LinkedIn post will finally be addressed – but only after a high‑profile disaster forces the change.
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