MEDIUM CVSS 5.3
Published: 2021-03-01

CVE-2020-36240

atlassian crowd Security Advisory (CVE-2020-36240)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2020-36240 impacting atlassian crowd. Evaluated with CVSS Base Score of 5.3 (MEDIUM).

Original NVD Description

Source: NIST NVD
The ResourceDownloadRewriteRule class in Crowd before version 4.0.4, and from version 4.1.0 before 4.1.2 allowed unauthenticated remote attackers to read arbitrary files within WEB-INF and META-INF directories via an incorrect path access check.

📊 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
Unchanged (S:U)
Confined to same security context
Confidentiality
Low (C:L)
Partial information leakage
Integrity
None (I:N)
No system modification impact
Availability
None (A:N)
No system availability impact

🎯 Affected Versions Matrix

Affected Product atlassian / crowd
Affected Versions *
Weakness Enumeration NVD-CWE-noinfo

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-2020-36240 impacting atlassian crowd.

⚡ Nuclei Detection Template (YAML) cve-2020-36240.yaml
id: cve-2020-36240

info:
  name: atlassian crowd - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2020-36240 affecting atlassian crowd.
    Evaluation: The ResourceDownloadRewriteRule class in Crowd before version 4.0.4, and from version 4.1.0 before 4.1.2 allowed unauthenticated remote attackers to r...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2020-36240
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
    cvss-score: 5.3
    cve-id: CVE-2020-36240
    cwe-id: NVD-CWE-noinfo
  tags: cve,cve-2020-36240,atlassian,crowd,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "crowd"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2020-36240.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2020-36240
# Target: atlassian crowd | CVSS: 5.3 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2020-36240 (atlassian crowd)...")
    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 atlassian crowd 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-2020-36240.sh
# Recommended Remediation & Patching Commands for CVE-2020-36240
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install crowd 2>/dev/null || \
sudo dnf upgrade crowd 2>/dev/null || \
sudo yum update crowd

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

# 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.

🔗 Verified Technical References

Authorities
  • No records filed in this category.
Distributions
  • No records filed in this category.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2020-36240 in atlassian crowd?

Review vendor-specific security notices and update atlassian crowd 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-2020-36240?

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-2020-36240?

CVE-2020-36240 is classified with a CVSS 3.1 Base Score of 5.3 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
5.3
MEDIUM SEVERITY
CVE ID CVE-2020-36240
Weakness NVD-CWE-noinfo
Vendor atlassian
Product crowd
Published 2021-03-01
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N