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Free AntivirusApplication · Avast

CVE-2017-5567

MEDIUM · 6.7 CVSS v3.0 Published 2017-03-21
Fix available
A fix is available. Upgrade to after 12.3 or later.
See remediation →
69/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Avast antivirus products 12.3 and earlier lack Windows Protected Processes functionality, allowing local attackers to inject arbitrary code via Image File Execution Options (IFEO) registry manipulation. The self-protection mechanism blocks modification of IFEO keys for Avast processes but can be bypassed by temporarily renaming the IFEO registry key during the attack, achieving code execution within any Avast process.

MitigationUsers should upgrade Avast products to a version beyond 12.3 where Protected Processes are implemented. The vendor has addressed this by redesigning the self-protection mechanism.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Free AntivirusApplication
Affected:<= 12.3
Internet SecurityApplication
Affected:<= 12.3
PremierApplication
Affected:<= 12.3
Pro AntivirusApplication
Affected:<= 12.3

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed Avast version
    Open Avast user interface, go to Menu > Settings > About, or check registry at HKLM\SOFTWARE\Avast Software\Avast\Version (or HKLM\SOFTWARE\AVAST Software\Avast for 32-bit installations)
    Affected if Version number is 12.3 or lower (for example 12.2, 12.1, 12.0, or any build <= 12.3)
  2. Identify Avast product edition
    Check registry at HKLM\SOFTWARE\Avast Software\Avast\Product or inspect installed programs in Control Panel > Programs and Features
    Affected if Product is Avast Free Antivirus, Avast Internet Security, Avast Premier, or Avast Pro Antivirus with version <= 12.3
  3. Verify IFEO registry key accessibility
    Use regedit to navigate to HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options and check if the security permissions allow modification (right-click key > Permissions > check if non-admin users can modify)
    Affected if IFEO registry keys for Avast processes (such as avastsvc.exe, avastui.exe, avp.exe) can be modified by the current user or by malware running with user privileges
  4. Confirm self-protection status
    Attempt to create or modify a test key under HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\avastsvc.exe (or other Avast process names) to see if Avast self-protection blocks the change
    Affected if Modification succeeds or the self-protection mechanism can be bypassed by renaming the IFEO key temporarily, indicating the Protected Processes feature is not implemented

You are affected if running any Avast Free Antivirus, Internet Security, Premier, or Pro Antivirus version 12.3 or earlier, where the IFEO registry keys can be manipulated due to missing Windows Protected Processes functionality.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to a release after 12.3
Interim mitigation

Users should upgrade Avast products to a version beyond 12.3 where Protected Processes are implemented. The vendor has addressed this by redesigning the self-protection mechanism.

Fix this in Free Antivirus Scoped from the published advisory
  • Consultation8.0 h
  • Implementation80.0 h
  • Testing40.0 h
  • Review / QA16.0 h
144.0 hours of engineering $24,880
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $39,808.

Scan for this in your stack

Free · runs locally
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2017-5567 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data