# CVE-2018-4839: Weak cryptography in DIGSI 4

> Attackers with local access or privileged network position can reconstruct access authorization passwords due to weak cryptography in Siemens SIPROTEC relays.

- **Severity:** Medium 5.3 (`CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 8 Mar 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-qm8x-gp66-4vfh

## What is CVE-2018-4839?

CVE-2018-4839 is a medium-severity vulnerability in Siemens DIGSI 4, published on 8 Mar 2018. Any signed-in user can exploit it over the network, 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), Other SIPROTEC 4 relays (All versions), Other SIPROTEC Compact relays (All versions), SIPROTEC 4 7SD80 (All versions < V4.70), SIPROTEC 4 7SJ61 (All versions < V4.96), SIPROTEC 4 7SJ62 (All versions < V4.96), SIPROTEC 4 7SJ64 (All versions < V4.96), SIPROTEC 4 7SJ66 (All versions < V4.30), SIPROTEC Compact 7SJ80 (All versions < V4.77), SIPROTEC Compact 7SK80 (All versions < V4.77). An attacker with local access to the engineering system or in a privileged network position and able to obtain certain network traffic could possibly reconstruct access authorization passwords.

Weakness: CWE-326 (Inadequate Encryption Strength)

## Which versions are affected by CVE-2018-4839?

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-2018-4839?

No fix has been published for CVE-2018-4839 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-4839 being exploited?

There is no known exploitation of CVE-2018-4839 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-2018-4840](https://insights.sbomify.com/CVE-2018-4840/): Missing authorization in DIGSI 4 (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-4839 and fix it if it is affected.

What it is: CVE-2018-4839 is a medium-severity vulnerability in Siemens DIGSI 4, published on 8 Mar 2018. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2018-4839 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-2018-4839/ (Markdown: https://insights.sbomify.com/CVE-2018-4839/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-4839
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-4839
- OSV: https://osv.dev/vulnerability/CVE-2018-4839

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-4839/
Summaries are generated and may contain mistakes; the official description above is the record.