# CVE-2009-3677: Auth bypass in n/a

> Remote attackers can bypass MS-CHAP v2 PEAP authentication in Windows IAS to access network resources without valid credentials.

- **Severity:** Critical 10.0 (`AV:N/AC:L/Au:N/C:C/I:C/A:C`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 9 Dec 2009
- **Updated:** 7 Aug 2024
- **Also known as:** GHSA-24hh-hrh3-7p5w

## What is CVE-2009-3677?

CVE-2009-3677 is a critical authentication bypass vulnerability in Microsoft Windows 2000, published on 9 Dec 2009. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The Internet Authentication Service (IAS) in Microsoft Windows 2000 SP4, XP SP2 and SP3, Server 2003 SP2, Vista Gold and SP1, and Server 2008 Gold does not properly verify the credentials in an MS-CHAP v2 Protected Extensible Authentication Protocol (PEAP) authentication request, which allows remote attackers to access network resources via a malformed request, aka "MS-CHAP Authentication Bypass Vulnerability."

Weakness: CWE-94 (Improper Control of Generation of Code), CWE-255

## Which versions are affected by CVE-2009-3677?

It affects 5 products.


Products: Microsoft Windows 2000, Microsoft Windows Server 2003, Microsoft Windows Server 2008, Microsoft Windows Vista, Microsoft Windows Xp.

## How do I fix CVE-2009-3677?

No fix has been published for CVE-2009-3677 yet. Limit exposure of the affected software until one is available.

## Is CVE-2009-3677 being exploited?

There is no known exploitation of CVE-2009-3677 in the wild and no public exploit code.

## Other vulnerabilities in Microsoft Windows 2000

- [CVE-2008-4250](https://insights.sbomify.com/CVE-2008-4250/): Microsoft Windows Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2010-0232](https://insights.sbomify.com/CVE-2010-0232/): Microsoft Windows Kernel Exception Handler (high 7.8, exploited in the wild)
- [CVE-2009-1123](https://insights.sbomify.com/CVE-2009-1123/): Microsoft Windows Improper Input Validation (high 7.8, exploited in the wild)
- [CVE-2002-0367](https://insights.sbomify.com/CVE-2002-0367/): Microsoft Windows Privilege Escalation (high 7.8, exploited in the wild)
- [CVE-2010-0269](https://insights.sbomify.com/CVE-2010-0269/): Memory corruption in n/a (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2009-3677 and fix it if it is affected.

What it is: CVE-2009-3677 is a critical authentication bypass vulnerability in Microsoft Windows 2000, published on 9 Dec 2009. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2009-3677 in the wild and no public exploit code.

Affected product: Microsoft Windows 2000. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2009-3677/ (Markdown: https://insights.sbomify.com/CVE-2009-3677/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2009-3677
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2009-3677
- OSV: https://osv.dev/vulnerability/CVE-2009-3677

---
From sbomify Insights: https://insights.sbomify.com/CVE-2009-3677/
Summaries are generated and may contain mistakes; the official description above is the record.