What is CVE-2019-0056?A high-severity flaw in Junos, explained.

High severity6 affected products
The short answer

CVE-2019-0056 is a high-severity flaw (CVSS 7.5) in Junos from Juniper, published on 9 October 2019. 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 1.3%. If you run an affected version, plan in the vendor’s fix.

Published 9 October 2019. Record last updated 28 October 2021. We keep this page's data up to date.

What it does

What is CVE-2019-0056? 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 take it offline.

The official description

This issue only affects devices with three (3) or more MPC10's installed in a single chassis with OSPF enabled and configured on the device. An Insufficient Resource Pool weakness allows an attacker to cause the device's Open Shortest Path First (OSPF) states to transition to Down, resulting in a Denial of Service (DoS) attack. This attack requires a relatively large number of specific Internet Mixed (IMIXed) types of genuine and valid IPv6 packets to be transferred by the attacker in a relatively short period of time, across three or more PFE's on the device at the same time. Continued receipt of the traffic sent by the attacker will continue to cause OSPF to remain in the Down starting state, or flap between other states and then again to Down, causing a persistent Denial of Service. This attack will affect all IPv4, and IPv6 traffic served by the OSPF routes once the OSPF states transition to Down. This issue affects: Juniper Networks Junos OS on MX480, MX960, MX2008, MX2010, MX2020: 18.1 versions prior to 18.1R2-S4, 18.1R3-S5; 18.1X75 version 18.1X75-D10 and later versions; 18.2 versions prior to 18.2R1-S5, 18.2R2-S3, 18.2R3; 18.2X75 versions prior to 18.2X75-D50; 18.3 versions prior to 18.3R1-S4, 18.3R2, 18.3R3; 18.4 versions prior to 18.4R1-S2, 18.4R2.

What kind of flaw is it?

  • CWE-410Insufficient Resource Pool
CVSS 3.1 scoreHigh · 7.5

How an attack on it works

Read straight from its severity rating, translated out of the shorthand.

  • Where an attacker can beAnywhere on the internet
  • 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:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation

Is CVE-2019-0056 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 1.3%. That can change at any time, which is why we keep watching.

Known to be exploitedNoNot on the list of exploited flaws today
Chance of use in the next 30 days1.3%Its EPSS score, from the latest forecast

Timeline

  1. Published
  2. Record last updated
How Precursor Intelligence ranks it
49out of 100Medium

CVE-2019-0056 scores 49. Action: Plan remediation.

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-2019-0056 matches software you track, it lands in your list with its score and the reasons behind it.

See your own ranked list →
Affected products

Who is affected by CVE-2019-0056? 6 products.

The published record lists 6 products from 1 vendor. If you run one of these, check your version, then go to the fix below.

  • Operating system

    Junos

    by Juniper

    Affected versions
    18.118.1-r218.1-r2-s118.1-r2-s218.1-r318.1-r3-s218.1-r3-s318.1-r3-s418.1x75-d1018.218.2-r2-s118.2-r2-s218.2x7518.2x75-d20
  • Hardware

    Mx2008

    by Juniper

    Affected versions
    version not specified
  • Hardware

    Mx2010

    by Juniper

    Affected versions
    version not specified
  • Hardware

    Mx2020

    by Juniper

    Affected versions
    version not specified
  • Hardware

    Mx480

    by Juniper

    Affected versions
    version not specified
  • Hardware

    Mx960

    by Juniper

    Affected versions
    version not specified
Remediation

How do I fix CVE-2019-0056? Four steps.

  1. 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.
  2. Apply the vendor’s fixInstall the update named in the vendor’s advisory. We’ve put the advisory first in the list.
  3. 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.
  4. 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.

References

1 link
Precursor Intelligence

Does CVE-2019-0056 affect you? We'll keep checking.

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FAQ

Common questions, answered plainly.

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CVE-2019-0056 is a high-severity flaw in Junos from Juniper, published on 9 October 2019. It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can take it offline.

It scores 7.5 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2019-0056 is 49 out of 100, which is Medium. Its action is "Plan remediation". 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 1.3%. That can change at any time, which is why we keep watching.

For Junos from Juniper: 18.1, 18.1-r2, 18.1-r2-s1, 18.1-r2-s2, 18.1-r3, 18.1-r3-s2 and 16 more. The record lists 6 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.