# What is CVE-2020-25237?

> CVE-2020-25237 is a high-severity flaw (CVSS 8.1) in Sinema Server from Siemens, published on 9 February 2021. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 21%. If you run an affected version, plan in the vendor’s fix.

Canonical page: https://www.precursorintelligence.com/what-is/cve-2020-25237

## At a glance

- **Verdict:** Fix this soon. Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month.
- **Precursor Intelligence risk score:** 49 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes.
- **Severity:** High (CVSS 8.1 out of 10)
- **Known to be exploited:** No, not on the list of flaws known to be exploited today
- **Chance of use in the next 30 days:** 21% (latest exploit-likelihood forecast)
- **Published:** 9 February 2021
- **Record last updated:** 10 March 2021
- **Main product:** Sinema Server from Siemens
- **Affected products:** 2

## What is CVE-2020-25237? In plain terms

It can be attacked from anywhere on the internet with an ordinary user account, and nobody has to click anything. If it works, the attacker can change data and take it offline.

### The official description

A vulnerability has been identified in SINEC NMS (All versions < V1.0 SP1 Update 1), SINEMA Server (All versions < V14.0 SP2 Update 2). When uploading files to an affected system using a zip container, the system does not correctly check if the relative file path of the extracted files is still within the intended target directory. With this an attacker could create or overwrite arbitrary files on an affected system. This type of vulnerability is also known as 'Zip-Slip'. (ZDI-CAN-12054)

### What kind of flaw is it?

- CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

### How an attack on it works

- Where an attacker can be: Anywhere on the internet
- How hard it is to pull off: Easy: no special conditions
- Login needed first: An ordinary user account
- Does someone have to click: No, nobody has to do anything
- What an attacker gets: Can change data and take it offline

Severity vector: `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H`

## Is CVE-2020-25237 being exploited? Not that we know of

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 21%. That can change at any time, which is why we keep watching.

Exploit likelihood over the last 7 days: 21%, 21%, 21%, 21%, 21%, 21%, 21%.

### Timeline

- 9 February 2021: Published
- 10 March 2021: Record last updated
- 16 June 2026: Exploit likelihood jumped

### How Precursor Intelligence ranks it

CVE-2020-25237 scores **49 out of 100 (Medium)**, with the action "Plan remediation".

Every published flaw gets a risk score from 0 to 100, kept up to date as the evidence changes. Four things go into the score, from the one that counts most to the ones that count less:

- Evidence it is being exploited: biggest factor
- How severe it is: strong factor
- How widely exposed it is: smaller factor
- Threat activity around it: smaller factor

85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score. When this flaw matches software you track, it lands in your list with its score and the reasons behind it.

## Who is affected by CVE-2020-25237?

The published record lists 2 products. Versions are as published: "before 14.0" means every version up to, but not including, 14.0.

- [Sinema Server](https://www.precursorintelligence.com/product/siemens/sinema_server) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Application): before 14.0, 14.0, 14.0-sp1, 14.0-sp2, 14.0-sp2_update1
- [Sinec Network Management System](https://www.precursorintelligence.com/product/siemens/sinec_network_management_system) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Application): before 1.0, 1.0, 1.0-sp1

## How do I fix CVE-2020-25237?

1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list.
2. **Apply the vendor’s fix.** Install the update named in the vendor’s advisory. We’ve put the advisory first in the list.
3. **If you can’t patch today.** Follow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in.
4. **Keep an eye on it.** Track the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood.

### References

- [cert-portal.siemens.com](https://cert-portal.siemens.com/productcert/pdf/ssa-156833.pdf) (Vendor advisory)
- [us-cert.cisa.gov](https://us-cert.cisa.gov/ics/advisories/icsa-21-040-03) (Third-party advisory, Government resource)
- [zerodayinitiative.com](https://www.zerodayinitiative.com/advisories/ZDI-21-253/) (Third-party advisory, Vulnerability database)

## Questions

### What is CVE-2020-25237?

CVE-2020-25237 is a high-severity flaw in Sinema Server from Siemens, published on 9 February 2021. It can be attacked from anywhere on the internet with an ordinary user account, and nobody has to click anything. If it works, the attacker can change data and take it offline.

### How serious is CVE-2020-25237?

It scores 8.1 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2020-25237 is 49 out of 100, which is Medium. Its action is "Plan remediation". Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month.

### Is CVE-2020-25237 being exploited?

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 21%. That can change at any time, which is why we keep watching.

### Which versions does CVE-2020-25237 affect?

For Sinema Server from Siemens: before 14.0, 14.0, 14.0-sp1, 14.0-sp2, 14.0-sp2_update1. The record lists 2 products in all, each with its versions, under "Who is affected" on this page.

### How do I fix CVE-2020-25237?

Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet.

## Does CVE-2020-25237 affect you?

Precursor Intelligence keeps checking for you:

- **Tell us what you run.** Pick your software from a list, or let us work it out from your website.
- **We match it to every flaw.** Over 400,000 published flaws, checked against your list.
- **Ranked by real-world risk.** Every flaw gets a 0 to 100 risk score, kept up to date, led by evidence criminals are using it.
- **Told as soon as we know.** An alert by email, in the app or by webhook to your own tools.

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