# CVE-2017-8558: Memory corruption in Microsoft Malware Protection Engine

> Remote attackers can execute arbitrary code by sending a specially crafted file to the Microsoft Malware Protection Engine.

- **Severity:** High 7.8 (`CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 Jun 2017
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-ghvf-8cx5-ch3h

## What is CVE-2017-8558?

CVE-2017-8558 is a high-severity memory corruption vulnerability in Microsoft Malware Protection Engine, published on 29 Jun 2017. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The Microsoft Malware Protection Engine running on Microsoft Forefront and Microsoft Defender on 32-bit versions of Microsoft Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, Windows 10 Gold, 1511, 1607, and 1703 does not properly scan a specially crafted file leading to memory corruption. aka "Microsoft Malware Protection Engine Remote Code Execution Vulnerability".

Weakness: CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2017-8558?

It affects 5 products.


Products: Microsoft Endpoint Protection, Microsoft Forefront Endpoint Protection, Microsoft Security Essentials, Microsoft Windows Defender, Microsoft Windows Intune Endpoint Protection.

## How do I fix CVE-2017-8558?

No fix has been published for CVE-2017-8558 yet. Limit exposure of the affected software until one is available.

## Is CVE-2017-8558 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2017-8558 exists.

Public exploit code:

- Microsoft MsMpEng - mpengine x86 Emulator Heap Corruption in VFS API (exploitdb)

## Other vulnerabilities in Microsoft Malware Protection Engine

- [CVE-2017-8540](https://insights.sbomify.com/CVE-2017-8540/): Microsoft Malware Protection Engine Improper Restriction of Operations (high 7.8, exploited in the wild)
- [CVE-2021-24092](https://insights.sbomify.com/CVE-2021-24092/): Microsoft Defender Elevation of Privilege Vulnerability (high 7.8)
- [CVE-2017-8535](https://insights.sbomify.com/CVE-2017-8535/): Denial of service in Malware Protection Engine (medium 5.5)
- [CVE-2017-8536](https://insights.sbomify.com/CVE-2017-8536/): Denial of service in Malware Protection Engine (medium 5.5)
- [CVE-2017-8537](https://insights.sbomify.com/CVE-2017-8537/): Denial of service in Malware Protection Engine (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-8558 and fix it if it is affected.

What it is: CVE-2017-8558 is a high-severity memory corruption vulnerability in Microsoft Malware Protection Engine, published on 29 Jun 2017. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2017-8558 exists.

Affected product: Microsoft Malware Protection Engine. 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-2017-8558/ (Markdown: https://insights.sbomify.com/CVE-2017-8558/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-8558
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-8558
- OSV: https://osv.dev/vulnerability/CVE-2017-8558

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From sbomify Insights: https://insights.sbomify.com/CVE-2017-8558/
Summaries are generated and may contain mistakes; the official description above is the record.