MEDIUM CVSS 6.7
Published: 2017-03-21

CVE-2017-5567

avast free_antivirus Security Advisory (CVE-2017-5567)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2017-5567 impacting avast free_antivirus. Evaluated with CVSS Base Score of 6.7 (MEDIUM).

Original NVD Description

Source: NIST NVD
Code injection vulnerability in Avast Premier 12.3 (and earlier), Internet Security 12.3 (and earlier), Pro Antivirus 12.3 (and earlier), and Free Antivirus 12.3 (and earlier) allows a local attacker to bypass a self-protection mechanism, inject arbitrary code, and take full control of any Avast process via a "DoubleAgent" attack. One perspective on this issue is that (1) these products do not use the Protected Processes feature, and therefore an attacker can enter an arbitrary Application Verifier Provider DLL under Image File Execution Options in the registry; (2) the self-protection mechanism is intended to block all local processes (regardless of privileges) from modifying Image File Execution Options for these products; and (3) this mechanism can be bypassed by an attacker who temporarily renames Image File Execution Options during the attack.

📊 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
High (PR:H)
Administrative credentials 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 avast / free_antivirus
Affected Versions *
Weakness Enumeration CWE-427

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-2017-5567 impacting avast free_antivirus.

⚡ Nuclei Detection Template (YAML) cve-2017-5567.yaml
id: cve-2017-5567

info:
  name: avast free_antivirus - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2017-5567 affecting avast free_antivirus.
    Evaluation: Code injection vulnerability in Avast Premier 12.3 (and earlier), Internet Security 12.3 (and earlier), Pro Antivirus 12.3 (and earlier), and Free Ant...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2017-5567
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 6.7
    cve-id: CVE-2017-5567
    cwe-id: CWE-427
  tags: cve,cve-2017-5567,avast,free_antivirus,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "free_antivirus"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2017-5567.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2017-5567
# Target: avast free_antivirus | CVSS: 6.7 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2017-5567 (avast free_antivirus)...")
    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 avast free_antivirus 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-2017-5567.sh
# Recommended Remediation & Patching Commands for CVE-2017-5567
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install free_antivirus 2>/dev/null || \
sudo dnf upgrade free_antivirus 2>/dev/null || \
sudo yum update free_antivirus

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

# 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-2017-5567 in avast free_antivirus?

Review vendor-specific security notices and update avast free_antivirus 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-2017-5567?

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-2017-5567?

CVE-2017-5567 is classified with a CVSS 3.1 Base Score of 6.7 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
6.7
MEDIUM SEVERITY
CVE ID CVE-2017-5567
Weakness CWE-427
Vendor avast
Product free_antivirus
Published 2017-03-21
Vector CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H