What it does. 'Performs vulnerability remediation on endpoints by prioritizing CVEs Part of mukul975/Anthropic-Cybersecurity-Skills (817 security skills) (mukul975/Anthropic-Cybersecurity-Skills).
Install
npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill performing-endpoint-vulnerability-remediation, or copy the skill folder into ~/.claude/skills/performing-endpoint-vulnerability-remediation/.- Raw file:
curl -sL https://raw.githubusercontent.com/mukul975/Anthropic-Cybersecurity-Skills/HEAD/skills/performing-endpoint-vulnerability-remediation/SKILL.md
SKILL.md (verbatim)
name: performing-endpoint-vulnerability-remediation
description: 'Performs vulnerability remediation on endpoints by prioritizing CVEs
based on risk scoring, deploying patches, applying configuration changes, and validating
fixes. Use when remediating findings from vulnerability scans, responding to critical
CVE advisories, or maintaining endpoint compliance with patch management SLAs. Activates
for requests involving vulnerability remediation, CVE patching, endpoint vulnerability
management, or security fix deployment.
'
domain: cybersecurity
subdomain: endpoint-security
tags:
- endpoint
- vulnerability-management
- patching
- CVE
- remediation
- CVSS
version: 1.0.0
author: mahipal
license: Apache-2.0
nist_csf:
- PR.PS-01
- PR.PS-02
- DE.CM-01
- PR.IR-01
mitre_attack:
- T1055
- T1547
- T1059
- T1036
Performing Endpoint Vulnerability Remediation
When to Use
Use this skill when:
- Remediating vulnerabilities identified by scanners (Nessus, Qualys, Rapid7)
- Responding to zero-day CVE advisories requiring immediate patching
- Maintaining compliance with patch management SLAs (critical within 14 days, high within 30 days)
- Building a prioritized remediation plan from vulnerability scan results
Do not use this skill for vulnerability scanning itself (use scanning tools) or for application-layer vulnerability remediation (use DevSecOps processes).
Prerequisites
- Vulnerability scan results (Nessus, Qualys, or Rapid7 export in CSV/XML format)
- Patch management platform (WSUS, SCCM, Intune, or third-party like Automox)
- Administrative access to target endpoints or deployment infrastructure
- Change management process for production endpoint patching
- Testing environment for patch validation before production rollout
Workflow
Step 1: Import and Prioritize Vulnerability Findings
Priority scoring combines:
1. CVSS Base Score (0-10)
2. EPSS (Exploit Prediction Scoring System) - probability of exploitation
3. CISA KEV (Known Exploited Vulnerabilities) catalog membership
4. Asset criticality (business impact of affected endpoint)
5. Network exposure (internet-facing vs. internal)
Priority Matrix:
P1 (Critical - 14 days SLA):
- CVSS >= 9.0 OR
- Listed in CISA KEV OR
- Active exploitation in the wild + CVSS >= 7.0
P2 (High - 30 days SLA):
- CVSS 7.0-8.9 AND
- EPSS > 0.5 (50% probability of exploitation)
P3 (Medium - 60 days SLA):
- CVSS 4.0-6.9 OR
- CVSS 7.0-8.9 with EPSS < 0.1
P4 (Low - 90 days SLA):
- CVSS < 4.0 AND
- No known exploit
For each vulnerability, determine the appropriate remediation:
Remediation Types:
1. Patch: Apply vendor security update (most common)
2. Configuration change: Modify settings to mitigate (registry, GPO)
3. Upgrade: Update to newer software version
4. Workaround: Apply temporary mitigation when patch unavailable
5. Compensating control: Network segmentation, WAF rule, EDR rule
6. Accept risk: Document accepted risk with CISO sign-off
Step 3: Deploy Patches via WSUS/SCCM
# WSUS: Approve patches for deployment
# 1. Open WSUS Console
# 2. Navigate to Updates → Security Updates
# 3. Approve selected KBs for target computer groups
# SCCM: Create Software Update Group
# 1. Software Library → Software Updates → All Software Updates
# 2. Select required KBs → Create Software Update Group
# 3. Deploy to target collection with maintenance window
# Intune: Create Windows Update Ring
# Devices → Windows → Update rings
# Configure: Quality updates deferral = 0 days (for critical)
# Feature updates deferral = per policy
# PowerShell: Force Windows Update check
Install-Module PSWindowsUpdate -Force
Get-WindowsUpdate -KBArticleID "KB5034441" -Install -AcceptAll -AutoReboot
# Verify patch installation
Get-HotFix -Id "KB5034441"
systeminfo | findstr "KB5034441"
# Example: Disable SMBv1 (CVE-2017-0144 - EternalBlue)
Set-SmbServerConfiguration -EnableSMB1Protocol $false -Force
Disable-WindowsOptionalFeature -Online -FeatureName SMB1Protocol -NoRestart
# Example: Disable Print Spooler on non-print servers (CVE-2021-34527 - PrintNightmare)
Stop-Service -Name Spooler -Force
Set-Service -Name Spooler -StartupType Disabled
# Example: Disable LLMNR (credential theft mitigation)
# Via GPO: Computer Configuration → Admin Templates → Network → DNS Client
# Turn off multicast name resolution: Enabled
New-ItemProperty -Path "HKLM:\SOFTWARE\Policies\Microsoft\Windows NT\DNSClient" `
-Name EnableMulticast -Value 0 -PropertyType DWORD -Force
# Example: Restrict NTLM authentication
# Via GPO: Security Settings → Local Policies → Security Options
# Network security: Restrict NTLM: Audit/Deny
Step 5: Handle Zero-Day Vulnerabilities (No Patch Available)
When vendor patch is not yet available:
1. Check vendor advisory for workarounds
- Microsoft: https://msrc.microsoft.com/update-guide
- Adobe: https://helpx.adobe.com/security.html
- Linux: Distribution security trackers
2. Apply temporary mitigations:
- Disable vulnerable feature/service
- Deploy EDR detection rule for exploitation attempt
- Apply network-level blocking (WAF/firewall rules)
- Restrict access to vulnerable application
3. Monitor for patch release:
- Subscribe to vendor security mailing list
- Monitor CISA KEV additions
- Set calendar reminder for next Patch Tuesday
4. Document workaround with expiration date
# Re-scan remediated endpoints to confirm vulnerability closure
# Option 1: Targeted vulnerability scan
nessuscli scan --target 192.168.1.0/24 --plugin-id 12345
# Option 2: PowerShell verification
# Check specific KB is installed
$kb = Get-HotFix -Id "KB5034441" -ErrorAction SilentlyContinue
if ($kb) {
Write-Host "PASS: KB5034441 installed on $(hostname)" -ForegroundColor Green
} else {
Write-Host "FAIL: KB5034441 missing on $(hostname)" -ForegroundColor Red
}
# Check service is disabled
$svc = Get-Service -Name Spooler
if ($svc.StartType -eq 'Disabled') {
Write-Host "PASS: Print Spooler disabled" -ForegroundColor Green
}
# Check registry configuration
$val = Get-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters" `
-Name SMB1 -ErrorAction SilentlyContinue
if ($val.SMB1 -eq 0) {
Write-Host "PASS: SMBv1 disabled" -ForegroundColor Green
}
Step 7: Report and Track
Generate remediation status report:
Remediation Metrics:
- Total vulnerabilities: X
- Remediated: Y (Z%)
- Pending (within SLA): A
- Overdue (past SLA): B
- Accepted risk: C
- Mean time to remediate (MTTR): D days
- SLA compliance rate: E%
Key Concepts
| Term |
Definition |
| CVSS |
Common Vulnerability Scoring System; 0-10 severity scale for vulnerabilities |
| EPSS |
Exploit Prediction Scoring System; probability (0-1) that a CVE will be exploited in the wild within 30 days |
| CISA KEV |
CISA Known Exploited Vulnerabilities catalog; federal mandate to patch these CVEs within specified timeframes |
| SLA |
Service Level Agreement for remediation timelines based on vulnerability severity |
| MTTR |
Mean Time To Remediate; average days from vulnerability discovery to confirmed fix |
| Compensating Control |
Alternative security measure when direct remediation is not feasible |
- Nessus/Tenable.io: Vulnerability scanning and remediation tracking
- Qualys VMDR: Vulnerability management, detection, and response platform
- Rapid7 InsightVM: Vulnerability assessment with live dashboards
- WSUS/SCCM/Intune: Microsoft patch deployment infrastructure
- Automox: Cloud-native patch management for Windows, macOS, Linux
- CISA KEV Catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
Common Pitfalls
- Patching without testing: Apply patches to a test group first. Some patches cause application compatibility issues or BSOD.
- Ignoring EPSS scores: A CVSS 9.8 vulnerability with EPSS 0.01 may be less urgent than a CVSS 7.5 with EPSS 0.95 (actively exploited).
- Not validating remediation: Deploying a patch does not guarantee installation. Always re-scan to confirm closure.
- Excluding critical servers from patching: Servers that "cannot be rebooted" accumulate critical vulnerabilities. Schedule maintenance windows.
- Treating all CVEs equally: Risk-based prioritization (CVSS + EPSS + asset criticality + exposure) is more effective than patching all criticals first.
Other files in this skill
assets/template.md (verbatim)
Endpoint Vulnerability Remediation Template
| Field |
Value |
| Scanner |
Nessus / Qualys / Rapid7 |
| Scan Date |
|
| Scope |
|
| Total Findings |
|
| Scan Policy |
|
| Priority |
Count |
SLA |
Deadline |
Status |
| P1 (Critical) |
|
14 days |
|
|
| P2 (High) |
|
30 days |
|
|
| P3 (Medium) |
|
60 days |
|
|
| P4 (Low) |
|
90 days |
|
|
| CVE |
Affected Hosts |
CVSS |
Due Date |
Remediation |
Status |
|
|
|
|
|
|
| CVE/Plugin |
Host(s) |
Action Type |
Details |
Assigned To |
Status |
|
|
Patch |
|
|
|
|
|
Config change |
|
|
|
|
|
Workaround |
|
|
|
|
|
Accept risk |
|
|
|
Patch Deployment Schedule
| Phase |
Target |
Date |
Maintenance Window |
Rollback Plan |
| Test ring |
5% endpoints |
|
|
|
| Pilot ring |
20% endpoints |
|
|
|
| Production |
Remaining |
|
|
|
Risk Acceptance Register
| CVE |
Host |
CVSS |
Business Justification |
Compensating Control |
Approved By |
Expiry |
|
|
|
|
|
|
|
Validation Results
| CVE/Plugin |
Host |
Pre-Remediation |
Post-Remediation |
Verified By |
|
|
Vulnerable |
Fixed / Still Vulnerable |
|
Metrics
| Metric |
Value |
| Total vulnerabilities |
|
| Remediated |
|
| Remediation rate |
% |
| MTTR (Mean Time to Remediate) |
days |
| SLA compliance |
% |
| Overdue count |
|
Sign-Off
| Role |
Name |
Date |
| Vulnerability Analyst |
|
|
| Patch Manager |
|
|
| Security Manager |
|
|
references/api-reference.md (verbatim)
API Reference — Performing Endpoint Vulnerability Remediation
Libraries Used
| Library |
Purpose |
csv |
Parse vulnerability scan CSV exports (Nessus, Qualys, Rapid7) |
subprocess |
Check installed Windows patches via wmic qfe and PowerShell |
socket |
Validate port-based remediation via TCP connect |
json |
Read/write remediation plans and reports |
argparse |
CLI argument parsing for scan file and host parameters |
datetime |
Track patch dates and SLA deadlines |
CLI Interface
python agent.py parse --scan-file scan.csv
python agent.py patches
python agent.py validate --host 10.0.0.1 --port 445
python agent.py report --scan-file scan.csv [--output plan.json]
Core Functions
parse_scan_report(csv_file) — Parse and prioritize vulnerabilities by severity
def parse_scan_report(csv_file):
"""Parse Nessus/Qualys CSV export, group by host, sort by severity."""
with open(csv_file, newline="") as f:
reader = csv.DictReader(f)
vulns = []
for row in reader:
vulns.append({
"host": row.get("Host", row.get("IP")),
"plugin_id": row.get("Plugin ID", row.get("QID")),
"severity": row.get("Risk", row.get("Severity", "Info")),
"name": row.get("Name", row.get("Title")),
"cve": row.get("CVE", ""),
"solution": row.get("Solution", row.get("Fix", "")),
})
severity_order = {"Critical": 0, "High": 1, "Medium": 2, "Low": 3, "Info": 4}
return sorted(vulns, key=lambda v: severity_order.get(v["severity"], 5))
check_windows_patches() — List installed Windows hotfixes via WMIC
def check_windows_patches():
"""Query installed patches on a Windows endpoint."""
result = subprocess.run(
["wmic", "qfe", "get", "HotFixID,InstalledOn,Description", "/format:csv"],
capture_output=True, text=True, timeout=30,
)
patches = []
for line in result.stdout.strip().split("\n")[1:]:
parts = line.strip().split(",")
if len(parts) >= 4:
patches.append({
"hotfix_id": parts[1],
"description": parts[2],
"installed_on": parts[3],
})
return patches
def validate_remediation(host, port):
"""Verify that a vulnerable port has been closed after remediation."""
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.settimeout(5)
try:
result = sock.connect_ex((host, int(port)))
return {
"host": host,
"port": port,
"status": "open" if result == 0 else "closed",
"remediated": result != 0,
}
finally:
sock.close()
def generate_remediation_report(scan_file, output=None):
"""Generate a prioritized remediation plan from scan results."""
vulns = parse_scan_report(scan_file)
by_host = {}
for v in vulns:
by_host.setdefault(v["host"], []).append(v)
report = {
"total_vulns": len(vulns),
"hosts_affected": len(by_host),
"by_severity": {},
"remediation_plan": [],
}
for severity in ["Critical", "High", "Medium", "Low"]:
count = sum(1 for v in vulns if v["severity"] == severity)
report["by_severity"][severity] = count
for host, host_vulns in sorted(by_host.items()):
report["remediation_plan"].append({
"host": host,
"vuln_count": len(host_vulns),
"critical": sum(1 for v in host_vulns if v["severity"] == "Critical"),
"patches": [v["name"] for v in host_vulns[:10]],
})
if output:
with open(output, "w") as f:
json.dump(report, f, indent=2)
return report
{
"total_vulns": 245,
"hosts_affected": 42,
"by_severity": {
"Critical": 8,
"High": 35,
"Medium": 112,
"Low": 90
},
"remediation_plan": [
{
"host": "10.0.0.50",
"vuln_count": 12,
"critical": 2,
"patches": ["MS17-010: EternalBlue", "CVE-2024-21887: Ivanti RCE"]
}
]
}
Dependencies
No external packages — Python standard library only.
references/standards.md (verbatim)
Standards & References - Performing Endpoint Vulnerability Remediation
Primary Standards
NIST SP 800-40 Rev 4 - Guide to Enterprise Patch Management Planning
CISA Binding Operational Directive 22-01 - Known Exploited Vulnerabilities
FIRST CVSS v3.1 Specification
FIRST EPSS Model
- Publisher: FIRST
- URL: https://www.first.org/epss/
- Scope: Machine learning model predicting probability of CVE exploitation within 30 days
Compliance Mappings
| Framework |
Requirement |
Remediation Coverage |
| PCI DSS 4.0 |
6.3.3 - Patch within one month of release |
Patch SLA tracking and compliance |
| PCI DSS 4.0 |
11.3.1 - Internal vulnerability scans quarterly |
Scan-remediate-validate cycle |
| NIST 800-53 |
SI-2 Flaw Remediation |
Vulnerability identification and patching |
| NIST 800-53 |
RA-5 Vulnerability Monitoring and Scanning |
Ongoing scan-remediate process |
| HIPAA |
164.308(a)(1)(ii)(B) - Risk Management |
Vulnerability remediation as risk reduction |
| ISO 27001 |
A.12.6.1 - Management of technical vulnerabilities |
Systematic vulnerability remediation |
| SOC 2 |
CC7.1 - Detect and address vulnerabilities |
Vulnerability management program |
| Severity |
CVSS Range |
Industry Standard SLA |
CISA KEV Timeline |
| Critical |
9.0-10.0 |
14 days |
Per directive (usually 14 days) |
| High |
7.0-8.9 |
30 days |
Per directive |
| Medium |
4.0-6.9 |
60 days |
N/A unless in KEV |
| Low |
0.1-3.9 |
90 days |
N/A |
Supporting References
references/workflows.md (verbatim)
Workflows - Performing Endpoint Vulnerability Remediation
[Vulnerability Scan Complete]
│
▼
[Import scan results into tracking system]
│
▼
[Risk-based prioritization]
│
├── CVSS + EPSS + CISA KEV + Asset criticality
│
▼
[Assign priorities: P1/P2/P3/P4]
│
▼
[Identify remediation action per CVE]
│
├── Patch available ──► [Schedule patch deployment]
├── Config change needed ──► [Create change request]
├── No patch available ──► [Apply workaround/compensating control]
└── Accept risk ──► [Document with CISO approval]
│
▼
[Test patches in staging environment]
│
▼
[Deploy to production (phased rollout)]
│
▼
[Re-scan to validate remediation]
│
├── Vulnerability closed ──► [Mark resolved in tracker]
│
└── Still open ──► [Investigate failure, re-remediate]
Workflow 2: Emergency Zero-Day Response
[Zero-day CVE announced (CISA alert / vendor advisory)]
│
▼
[Assess exposure: How many endpoints affected?]
│
▼
[Is patch available?]
│
├── Yes ──► [Emergency patch deployment (skip staging)]
│ │
│ ▼
│ [Monitor for deployment failures]
│ │
│ ▼
│ [Validate patch across fleet]
│
└── No ──► [Apply vendor workaround immediately]
│
├── Disable vulnerable service/feature
├── Deploy network-level mitigation
├── Create EDR detection rule
│
▼
[Monitor for patch release]
│
▼
[Deploy patch when available]
│
▼
[Remove workaround, validate fix]
Workflow 3: Patch Deployment Pipeline
[Patch Tuesday (or vendor release)]
│
▼
[Download and catalog new patches]
│
▼
[Risk assessment: Which patches are critical?]
│
▼
[Deploy to test ring (5% of fleet) - Day 1-3]
│
├── Test application compatibility
├── Monitor for BSOD, crashes, performance issues
│
▼
[Deploy to pilot ring (20% of fleet) - Day 4-7]
│
├── Broader application testing
├── User feedback collection
│
▼
[Deploy to production ring (remaining fleet) - Day 8-14]
│
▼
[Generate compliance report]
│
├── Endpoints patched: X%
├── Pending reboot: Y
└── Failed deployments: Z (investigate)
Workflow 4: SLA Compliance Tracking
[Weekly SLA Review]
│
▼
[Query open vulnerabilities grouped by SLA status]
│
├── Within SLA ──► [Track progress, no action needed]
│
├── Approaching SLA (7 days) ──► [Escalate to endpoint team]
│
└── Overdue (past SLA) ──► [Escalate to management]
│
├── Remediation feasible ──► [Emergency remediation]
│
└── Blocked (dependency) ──► [Document exception, compensating control]
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