# What is CVE-2020-6994?

> CVE-2020-6994 is a critical-severity flaw (CVSS 9.8) in Hirschmann Hios from Belden, published on 3 April 2020. 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 1.6%. If you run an affected version, plan in the vendor’s fix.

Canonical page: https://www.precursorintelligence.com/what-is/cve-2020-6994

## 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:** 55 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes.
- **Severity:** Critical (CVSS 9.8 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:** 1.6% (latest exploit-likelihood forecast)
- **Published:** 3 April 2020
- **Record last updated:** 17 June 2021
- **Main product:** Hirschmann Hios from Belden
- **Affected products:** 14

## What is CVE-2020-6994? In plain terms

It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline.

### The official description

A buffer overflow vulnerability was found in some devices of Hirschmann Automation and Control HiOS and HiSecOS. The vulnerability is due to improper parsing of URL arguments. An attacker could exploit this vulnerability by specially crafting HTTP requests to overflow an internal buffer. The following devices using HiOS Version 07.0.02 and lower are affected: RSP, RSPE, RSPS, RSPL, MSP, EES, EES, EESX, GRS, OS, RED. The following devices using HiSecOS Version 03.2.00 and lower are affected: EAGLE20/30.

### What kind of flaw is it?

- CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
- CWE-12: ASP.NET Misconfiguration: Missing Custom Error Page

### 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: No login needed
- Does someone have to click: No, nobody has to do anything
- What an attacker gets: Can read data, change data and take it offline

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

## Is CVE-2020-6994 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 1.6%. That can change at any time, which is why we keep watching.

Exploit likelihood over the last 7 days: 1.6%, 1.6%, 1.6%, 1.6%, 1.6%, 1.6%, 1.6%.

### Timeline

- 3 April 2020: Published
- 17 June 2021: Record last updated

### How Precursor Intelligence ranks it

CVE-2020-6994 scores **55 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-2020-6994?

The published record lists 14 products.

- [Hirschmann Hios](https://www.precursorintelligence.com/product/belden/hirschmann_hios) by [Belden](https://www.precursorintelligence.com/vendors/belden) (Operating system): up to 07.0.02
- [Hirschmann Eagle20](https://www.precursorintelligence.com/product/belden/hirschmann_eagle20) by [Belden](https://www.precursorintelligence.com/vendors/belden) (Hardware): version not specified
- [Hirschmann Eagle30](https://www.precursorintelligence.com/product/belden/hirschmann_eagle30) by [Belden](https://www.precursorintelligence.com/vendors/belden) (Hardware): version not specified
- [Hirschmann Embedded Ethernet Switch](https://www.precursorintelligence.com/product/belden/hirschmann_embedded_ethernet_switch) by [Belden](https://www.precursorintelligence.com/vendors/belden) (Hardware): version not specified
- [Hirschmann Embedded Ethernet Switch Extended](https://www.precursorintelligence.com/product/belden/hirschmann_embedded_ethernet_switch_extended) by [Belden](https://www.precursorintelligence.com/vendors/belden) (Hardware): version not specified
- [Hirschmann Greyhound Swtich](https://www.precursorintelligence.com/product/belden/hirschmann_greyhound_swtich) by [Belden](https://www.precursorintelligence.com/vendors/belden) (Hardware): version not specified
- [Hirschmann Hisecos](https://www.precursorintelligence.com/product/belden/hirschmann_hisecos) by [Belden](https://www.precursorintelligence.com/vendors/belden) (Operating system): up to 03.2.00
- [Hirschmann Mice Switch Power](https://www.precursorintelligence.com/product/belden/hirschmann_mice_switch_power) by [Belden](https://www.precursorintelligence.com/vendors/belden) (Hardware): version not specified
- [Hirschmann Octopus](https://www.precursorintelligence.com/product/belden/hirschmann_octopus) by [Belden](https://www.precursorintelligence.com/vendors/belden) (Hardware): version not specified
- [Hirschmann Prp Redbox](https://www.precursorintelligence.com/product/belden/hirschmann_prp_redbox) by [Belden](https://www.precursorintelligence.com/vendors/belden) (Hardware): version not specified
- [Hirschmann Rail Switch Power](https://www.precursorintelligence.com/product/belden/hirschmann_rail_switch_power) by [Belden](https://www.precursorintelligence.com/vendors/belden) (Hardware): version not specified
- [Hirschmann Rail Switch Power Enhanced](https://www.precursorintelligence.com/product/belden/hirschmann_rail_switch_power_enhanced) by [Belden](https://www.precursorintelligence.com/vendors/belden) (Hardware): version not specified
- [Hirschmann Rail Switch Power Lite](https://www.precursorintelligence.com/product/belden/hirschmann_rail_switch_power_lite) by [Belden](https://www.precursorintelligence.com/vendors/belden) (Hardware): version not specified
- [Hirschmann Rail Switch Power Smart](https://www.precursorintelligence.com/product/belden/hirschmann_rail_switch_power_smart) by [Belden](https://www.precursorintelligence.com/vendors/belden) (Hardware): version not specified

## How do I fix CVE-2020-6994?

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

- [us-cert.gov](https://www.us-cert.gov/ics/advisories/icsa-20-091-01) (Mitigation, Third-party advisory, Government resource)

## Questions

### What is CVE-2020-6994?

CVE-2020-6994 is a critical-severity flaw in Hirschmann Hios from Belden, published on 3 April 2020. It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline.

### How serious is CVE-2020-6994?

It scores 9.8 out of 10 on the CVSS severity scale, which is critical. Our risk score for CVE-2020-6994 is 55 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-2020-6994 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 1.6%. That can change at any time, which is why we keep watching.

### Which versions does CVE-2020-6994 affect?

For Hirschmann Hios from Belden: up to 07.0.02. The record lists 14 products in all, each with its versions, under "Who is affected" on this page.

### How do I fix CVE-2020-6994?

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-2020-6994 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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