What is CVE-2020-3120?A medium-severity flaw in IOS XR, explained.
CVE-2020-3120 is a medium-severity flaw (CVSS 6.5) in IOS XR from Cisco, published on 5 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 1.6%. If you run an affected version, plan in the vendor’s fix.
Published 5 February 2020. Record last updated 20 April 2023. We keep this page's data up to date.
What is CVE-2020-3120? In plain terms.
An attacker has to be on the same local network without logging in, and nobody has to click anything. If it works, the attacker can take it offline.
A vulnerability in the Cisco Discovery Protocol implementation for Cisco FXOS Software, Cisco IOS XR Software, and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to cause a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to a missing check when the affected software processes Cisco Discovery Protocol messages. An attacker could exploit this vulnerability by sending a malicious Cisco Discovery Protocol packet to an affected device. A successful exploit could allow the attacker to exhaust system memory, causing the device to reload. Cisco Discovery Protocol is a Layer 2 protocol. To exploit this vulnerability, an attacker must be in the same broadcast domain as the affected device (Layer 2 adjacent).
What kind of flaw is it?
- CWE-190Integer Overflow or Wraparound
How an attack on it works
Read straight from its severity rating, translated out of the shorthand.
- Where an attacker can beOn the same local network
- How hard it is to pull offEasy: no special conditions
- Login needed firstNo login needed
- Does someone have to clickNo, nobody has to do anything
- What an attacker getsCan take it offline
Severity vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Is CVE-2020-3120 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.
Timeline
- Published
- Record last updated
CVE-2020-3120 scores 29. Action: Monitor.
We keep the score of every published flaw up to date as the evidence changes. Four things go into the score, and evidence that criminals are actually using it counts most. In order:
- Evidence it is being exploitedBiggest factor
- How severe it isStrong factor
- How widely exposed it isSmaller factor
- Threat activity around itSmaller factor
85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score.
When CVE-2020-3120 matches software you track, it lands in your list with its score and the reasons behind it.
See your own ranked list →Who is affected by CVE-2020-3120? 144 products.
The published record lists 144 products from 1 vendor. Versions are shown as published: "before 5.2(1)sv3(4.1b)" means every version up to, but not including, 5.2(1)sv3(4.1b). If you run one of these, check your version, then go to the fix below.
- Operating system
IOS XR
by Cisco
Affected versions5.2.56.4.26.5.36.6.257.0.1 - Operating system
NX-OS
by Cisco
Affected versionsup to 5.2before 5.2(1)sv3(4.1b)before 7.3(6)n1(1)before 6.2(24)before 13.2(9b)5.2 to before 6.2(29) - Operating system
Firepower Extensible Operating System
by Cisco
Affected versionsup to 2.3.1.1732.6 to before 2.6.1.1872.7 to before 2.7.1.106 - Application
UCS Manager
by Cisco
Affected versionsbefore 3.2(3m)4.0 to before 4.0(4g) - Hardware
ASR 9000v
by Cisco
Affected versionsversion not specified - Hardware
ASR 9001
by Cisco
Affected versionsversion not specified - Hardware
ASR 9006
by Cisco
Affected versionsversion not specified - Hardware
ASR 9010
by Cisco
Affected versionsversion not specified - Hardware
ASR 9901
by Cisco
Affected versionsversion not specified
How do I fix CVE-2020-3120? Four steps.
- Check whether you run itCompare 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.
- Apply the vendor’s fixInstall the update named in the vendor’s advisory. We’ve put the advisory first in the list.
- If you can’t patch todayFollow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in.
- Keep an eye on itTrack 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.
Does CVE-2020-3120 affect you? We'll keep checking.
Looking flaws up one at a time doesn't scale. Tell us what you run once, and we tell you which flaws matter to you, in what order, and keep watching for new ones.
- Tell us what you runPick your software from a list, or let us work it out from your website.
- We match it to every flawOver 400,000 published flaws, checked against your list.
- Ranked by real-world riskA 0 to 100 score, led by evidence criminals are using it.
- Told as soon as we knowAn alert by email, in the app or by webhook to your own tools.
Free plan, no card needed. Nothing to install.
1 new flaw affects software Acme tracks
A vulnerability in the Cisco Discovery Protocol implementation for Cisco FXOS Software, Cisco IOS XR Software, and Cisco NX-OS Software could allow an unauth...
- Matched to
- IOS XR on Acme's software list
- What to do
- Plan in the vendor’s update
Sent to the alert recipients Acme chose. Also in the app and to Acme's webhook.
CVE-2020-3120 is a medium-severity flaw in IOS XR from Cisco, published on 5 February 2020. An attacker has to be on the same local network without logging in, and nobody has to click anything. If it works, the attacker can take it offline.
It scores 6.5 out of 10 on the CVSS severity scale, which is medium. Our risk score for CVE-2020-3120 is 29 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.
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.
For IOS XR from Cisco: 5.2.5, 6.4.2, 6.5.3, 6.6.25, 7.0.1. The record lists 144 products in all, each with its versions, under "Who is affected" on this page.
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.