HIGH CVSS 7.8
Published: 2017-08-14

CVE-2017-11156

synology download_station Security Advisory (CVE-2017-11156)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2017-11156 impacting synology download_station. Evaluated with CVSS Base Score of 7.8 (HIGH).

Original NVD Description

Source: NIST NVD
Synology Download Station 3.8.x before 3.8.5-3475 and 3.x before 3.5-2984 uses weak permissions (0777) for ui/dlm/btsearch directory, which allows remote authenticated users to execute arbitrary code by uploading an executable via unspecified vectors.

📊 CVSS v3.1 Metric Breakdown

Attack Vector
Local (AV:L)
Requires local system execution permissions
Attack Complexity
Low (AC:L)
No specialized conditions required
Privileges Required
Low (PR:L)
Standard user access required
User Interaction
None (UI:N)
Zero human interaction required
Scope
Unchanged (S:U)
Confined to same security context
Confidentiality
High (C:H)
Total information disclosure
Integrity
High (I:H)
Total modification of target system
Availability
High (A:H)
Total denial of service or shutdown

🎯 Affected Versions Matrix

Affected Product synology / download_station
Affected Versions 3.2-2295
Weakness Enumeration CWE-276

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-2017-11156 impacting synology download_station.

⚡ Nuclei Detection Template (YAML) cve-2017-11156.yaml
id: cve-2017-11156

info:
  name: synology download_station - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: high
  description: |
    Automated signature & scanner for CVE-2017-11156 affecting synology download_station.
    Evaluation: Synology Download Station 3.8.x before 3.8.5-3475 and 3.x before 3.5-2984 uses weak permissions (0777) for ui/dlm/btsearch directory, which allows rem...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2017-11156
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 7.8
    cve-id: CVE-2017-11156
    cwe-id: CWE-276
  tags: cve,cve-2017-11156,synology,download_station,high

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "download_station"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2017-11156.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2017-11156
# Target: synology download_station | CVSS: 7.8 (HIGH)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2017-11156 (synology download_station)...")
    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 synology download_station scope (3.2-2295).")
        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-2017-11156.sh
# Recommended Remediation & Patching Commands for CVE-2017-11156
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install download_station 2>/dev/null || \
sudo dnf upgrade download_station 2>/dev/null || \
sudo yum update download_station

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

# 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

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2017-11156 in synology download_station?

Review vendor-specific security notices and update synology download_station 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-2017-11156?

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-2017-11156?

CVE-2017-11156 is classified with a CVSS 3.1 Base Score of 7.8 (HIGH). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
7.8
HIGH SEVERITY
CVE ID CVE-2017-11156
Weakness CWE-276
Vendor synology
Product download_station
Published 2017-08-14
Vector CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H