dbcve.org
Anti VirusApplication · Avg

CVE-2017-5566

MEDIUM · 6.7 CVSS v3.0 Published 2017-03-21
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
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 AVG Ultimate 17.1 (and earlier), AVG Internet Security 17.1 (and earlier), and AVG AntiVirus FREE 17.1 (and earlier) allows a local attacker to bypass a self-protection mechanism, inject arbitrary code, and take full control of any AVG 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

Local privilege escalation vulnerability in AVG 17.1 and earlier allows attackers to bypass self-protection by temporarily renaming the Image File Execution Options registry key, then injecting an arbitrary Application Verifier Provider DLL to achieve code execution within AVG processes. The root cause is AVG's failure to implement Windows Protected Processes feature.

MitigationUpdate to a patched AVG version that implements Protected Processes or applies the vendor fix; alternatively, monitor registry modifications to Image File Execution Options keys as a detective control.

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
Anti VirusApplication
Affected:= 17.1
Internet SecurityApplication
Affected:= 17.1
UltimateApplication
Affected:= 17.1

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 AVG version
    Open AVG and navigate to Menu > Settings > About, or check Programs and Features in Control Panel for AVG product version
    Affected if Version is 17.1 or earlier (the exact version shown matches 17.1)
  2. Confirm AVG product type
    Verify which AVG product is installed: Avg Anti Virus, Avg Internet Security, or Avg Ultimate
    Affected if Any of these three products is installed at version 17.1
  3. Inspect Image File Execution Options registry keys
    Open regedit and navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\ Look for keys named after AVG executable files (such as avgrsa.exe, avgfws.exe, or similar AVG process names)
    Affected if AVG self-protection registry keys exist in this location, indicating AVG relies on IFEO for protection rather than Windows Protected Processes
  4. Check for Application Verifier provider DLLs in AVG processes
    Use Process Explorer or similar tool to inspect running AVG processes and check for any DLLs loaded from Application Verifier (verifier.dll) or unexpected DLLs in AVG process memory space
    Affected if Arbitrary or unexpected DLLs are loaded into AVG processes, indicating successful injection
  5. Review AVG process integrity level
    Use Process Explorer or tasklist /v to check the integrity level of running AVG processes
    Affected if AVG processes run at Medium or low integrity rather than protected process integrity level

A system is affected if AVG version 17.1 (or any earlier version) is installed and the product does not implement Windows Protected Processes, leaving Image File Execution Options as the sole self-protection mechanism.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update to a patched AVG version that implements Protected Processes or applies the vendor fix; alternatively, monitor registry modifications to Image File Execution Options keys as a detective control.

Fix this in Anti Virus Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,770
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,832.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2017-5566 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2017-5566 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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