dbcve.org
Internet Authentication Service Helper Com ComponentApplication · Microsoft

CVE-2008-4299

MEDIUM · 5.0 CVSS v2.0 Published 2008-09-29
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
59/100
Remediation priority · Elevated
Remotely reachable No privileges 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
A certain ActiveX control in the Microsoft Internet Authentication Service (IAS) Helper COM Component in iashlpr.dll allows remote attackers to cause a denial of service (browser crash) via a large integer value in the first argument to the PutProperty method. NOTE: this issue was disclosed by an unreliable researcher, so it might be incorrect.

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 · low confidence

An ActiveX control in the Microsoft Internet Authentication Service (IAS) Helper COM Component (iashlpr.dll) contains a vulnerability where passing an excessively large integer value to the PutProperty method causes a denial of service resulting in browser crash. This is a client-side DoS vulnerability in a legacy Windows authentication service component.

MitigationDisable the affected iashlpr.dll ActiveX control in the browser via kill bit or registry restrictions, or uninstall the IAS component if not needed. Apply any available Microsoft security updates for this component.

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
Internet Authentication Service Helper Com ComponentApplication
Affected:all versions

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
Network
Complexity
Low
Authentication
None
Confidentiality
None
Integrity
None
Availability
Partial

AV:N/AC:L/Au:N/C:N/I:N/A:P

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. Locate the iashlpr.dll file on the system
    Search for iashlpr.dll in system directories - typically found in %SystemRoot%\System32\ or %SystemRoot%\SysWOW64\ on 64-bit systems. Use command: dir /s C:\iashlpr.dll or Get-ChildItem -Path C:\ -Filter iashlpr.dll -Recurse -ErrorAction SilentlyContinue
    Affected if The file exists on the system, indicating the IAS Helper component is installed
  2. Verify the ActiveX control is registered
    Check COM registration in the Windows Registry under HKEY_CLASSES_ROOT\CLSID\ for the IAS Helper component CLSID. Run: reg query "HKEY_CLASSES_ROOT\CLSID" /s | findstr -i "iashlpr" or check HKEY_LOCAL_MACHINE\SOFTWARE\Classes\iashlpr.iashlpr.1
    Affected if The COM component is registered in the Windows registry, meaning it can be instantiated by Internet Explorer or other applications
  3. Check if the ActiveX control is blocked in Internet Explorer
    Inspect the Internet Explorer kill bit settings in the registry under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\ for the IAS Helper CLSID, or check HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\CurrentVersion\Ext\PreApproved
    Affected if The kill bit is NOT set (the control is not listed in the compatibility block keys), meaning the ActiveX control can run in the browser
  4. Determine if Internet Authentication Service (IAS) is installed
    Check for IAS presence via registry at HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\IAS or check installed programs. On Windows Server, use: sc query IAS or check Add/Remove Programs for Remote Server Administration Tools (RSAT)
    Affected if IAS or its administration tools are installed on the system, increasing likelihood of the vulnerable component being present and active

A user is affected if the iashlpr.dll file exists on their system AND the ActiveX control is registered and not blocked by a kill bit, allowing it to run in Internet Explorer or other browsers.

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

Disable the affected iashlpr.dll ActiveX control in the browser via kill bit or registry restrictions, or uninstall the IAS component if not needed. Apply any available Microsoft security updates for this component.

Fix this in Internet Authentication Service Helper Com Component Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,060
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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-2008-4299 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