# What is CVE-2020-3170? > CVE-2020-3170 is a medium-severity flaw (CVSS 5.3) in NX-OS from Cisco, published on 26 February 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 1.7%. If you run an affected version, plan in the vendor’s fix. Canonical page: https://www.precursorintelligence.com/what-is/cve-2020-3170 ## At a glance - **Verdict:** Plan it in. No sign of exploitation and a low forecast. Patch it in your normal update cycle. - **Precursor Intelligence risk score:** 21 out of 100 (Low); action: Monitor. Kept up to date as the evidence changes. - **Severity:** Medium (CVSS 5.3 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:** 1.7% (latest exploit-likelihood forecast) - **Published:** 26 February 2020 - **Record last updated:** 3 March 2020 - **Main product:** NX-OS from Cisco - **Affected products:** 16 ## What is CVE-2020-3170? 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 slow it down. ### The official description A vulnerability in the NX-API feature of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause an NX-API system process to unexpectedly restart. The vulnerability is due to incorrect validation of the HTTP header of a request that is sent to the NX-API. An attacker could exploit this vulnerability by sending a crafted HTTP request to the NX-API on an affected device. A successful exploit could allow the attacker to cause a denial of service (DoS) condition in the NX-API service; however, the Cisco NX-OS device itself would still be available and passing network traffic. Note: The NX-API feature is disabled by default. ### What kind of flaw is it? - CWE-20: Improper Input Validation ### 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 slow it down Severity vector: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L` ## Is CVE-2020-3170 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 1.7%. That can change at any time, which is why we keep watching. Exploit likelihood over the last 7 days: 1.7%, 1.7%, 1.7%, 1.7%, 1.7%, 1.7%, 1.7%. ### Timeline - 26 February 2020: Published - 3 March 2020: Record last updated ### How Precursor Intelligence ranks it CVE-2020-3170 scores **21 out of 100 (Low)**, with the action "Monitor". 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-2020-3170? The published record lists 16 products. Versions are as published: "before 8.4(1)" means every version up to, but not including, 8.4(1). - [NX-OS](https://www.precursorintelligence.com/product/cisco/nx-os) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Operating system): before 8.4(1), before 8.2(5) - [Mds 9132t](https://www.precursorintelligence.com/product/cisco/mds_9132t) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Mds 9148s](https://www.precursorintelligence.com/product/cisco/mds_9148s) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Mds 9148t](https://www.precursorintelligence.com/product/cisco/mds_9148t) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Mds 9216](https://www.precursorintelligence.com/product/cisco/mds_9216) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Mds 9216a](https://www.precursorintelligence.com/product/cisco/mds_9216a) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Mds 9216i](https://www.precursorintelligence.com/product/cisco/mds_9216i) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Mds 9222i](https://www.precursorintelligence.com/product/cisco/mds_9222i) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Mds 9506](https://www.precursorintelligence.com/product/cisco/mds_9506) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Mds 9509](https://www.precursorintelligence.com/product/cisco/mds_9509) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Mds 9513](https://www.precursorintelligence.com/product/cisco/mds_9513) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Mds 9706](https://www.precursorintelligence.com/product/cisco/mds_9706) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Mds 9710](https://www.precursorintelligence.com/product/cisco/mds_9710) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Mds 9718](https://www.precursorintelligence.com/product/cisco/mds_9718) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 7000](https://www.precursorintelligence.com/product/cisco/nexus_7000) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 7700](https://www.precursorintelligence.com/product/cisco/nexus_7700) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified ## How do I fix CVE-2020-3170? 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 - [tools.cisco.com](https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20200226-nxos-api-dos) (Vendor advisory) ## Questions ### What is CVE-2020-3170? CVE-2020-3170 is a medium-severity flaw in NX-OS from Cisco, published on 26 February 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 slow it down. ### How serious is CVE-2020-3170? It scores 5.3 out of 10 on the CVSS severity scale, which is medium. Our risk score for CVE-2020-3170 is 21 out of 100, which is Low. Its action is "Monitor". No sign of exploitation and a low forecast. Patch it in your normal update cycle. ### Is CVE-2020-3170 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 1.7%. That can change at any time, which is why we keep watching. ### Which versions does CVE-2020-3170 affect? For NX-OS from Cisco: before 8.4(1), before 8.2(5). The record lists 16 products in all, each with its versions, under "Who is affected" on this page. ### How do I fix CVE-2020-3170? 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-2020-3170 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. Start free (no card, nothing to install): https://www.precursorintelligence.com/register Book a demo: https://www.precursorintelligence.com/contact