# CVE-2018-4840: Missing authorization in DIGSI 4

> Unauthenticated remote attackers can upload modified device configurations to overwrite access authorization passwords in Siemens industrial automation products.

- **Severity:** High 7.5 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 8 Mar 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-2fqf-9j8p-6mg2

## What is CVE-2018-4840?

CVE-2018-4840 is a high-severity missing authorization vulnerability in Siemens DIGSI 4, published on 8 Mar 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability has been identified in DIGSI 4 (All versions < V4.92), EN100 Ethernet module DNP3 variant (All versions < V1.05.00), EN100 Ethernet module IEC 104 variant (All versions), EN100 Ethernet module IEC 61850 variant (All versions < V4.30), EN100 Ethernet module Modbus TCP variant (All versions), EN100 Ethernet module PROFINET IO variant (All versions). The device engineering mechanism allows an unauthenticated remote user to upload a modified device configuration overwriting access authorization passwords.

Weakness: CWE-306 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2018-4840?

It affects 9 products.


Products: Siemens Digsi 4, Siemens En100 Ethernet Module Dnp3 Firmware, Siemens En100 Ethernet Module Iec 104 Firmware, Siemens En100 Ethernet Module Iec 61850 Firmware, Siemens En100 Ethernet Module Modbus Tcp Firmware, Siemens En100 Ethernet Module Profinet Io Firmware, Siemens Siprotec 4 7sj66 Firmware, Siemens Siprotec Compact 7sj80 Firmware, Siemens Siprotec Compact 7sk80 Firmware.

## How do I fix CVE-2018-4840?

No fix has been published for CVE-2018-4840 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-4840 being exploited?

There is no known exploitation of CVE-2018-4840 in the wild and no public exploit code.

## Other vulnerabilities in Siemens DIGSI 4

- [CVE-2020-25245](https://insights.sbomify.com/CVE-2020-25245/): Privilege escalation in DIGSI 4 (high 7.8)
- [CVE-2018-4839](https://insights.sbomify.com/CVE-2018-4839/): Weak cryptography in DIGSI 4 (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-4840 and fix it if it is affected.

What it is: CVE-2018-4840 is a high-severity missing authorization vulnerability in Siemens DIGSI 4, published on 8 Mar 2018. 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-2018-4840 in the wild and no public exploit code.

Affected product: Siemens DIGSI 4. 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-2018-4840/ (Markdown: https://insights.sbomify.com/CVE-2018-4840/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-4840
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-4840
- OSV: https://osv.dev/vulnerability/CVE-2018-4840

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-4840/
Summaries are generated and may contain mistakes; the official description above is the record.