# What is CVE-2020-1617? > CVE-2020-1617 is a high-severity flaw (CVSS 7.5) in Junos from Juniper, published on 8 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-2020-1617 ## 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:** 48 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes. - **Severity:** High (CVSS 7.5 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:** 8 April 2020 - **Record last updated:** 5 February 2021 - **Main product:** Junos from Juniper - **Affected products:** 12 ## What is CVE-2020-1617? 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 occurs on Juniper Networks Junos OS devices which do not support Advanced Forwarding Interface (AFI) / Advanced Forwarding Toolkit (AFT). Devices using AFI and AFT are not exploitable to this issue. An improper initialization of memory in the packet forwarding architecture in Juniper Networks Junos OS non-AFI/AFT platforms which may lead to a Denial of Service (DoS) vulnerability being exploited when a genuine packet is received and inspected by non-AFT/AFI sFlow and when the device is also configured with firewall policers. This first genuine packet received and inspected by sampled flow (sFlow) through a specific firewall policer will cause the device to reboot. After the reboot has completed, if the device receives and sFlow inspects another genuine packet seen through a specific firewall policer, the device will generate a core file and reboot. Continued inspection of these genuine packets will create an extended Denial of Service (DoS) condition. Depending on the method for service restoration, e.g. hard boot or soft reboot, a core file may or may not be generated the next time the packet is received and inspected by sFlow. This issue affects: Juniper Networks Junos OS 17.4 versions prior to 17.4R2-S9, 17.4R3 on PTX1000 and PTX10000 Series, QFX10000 Series; 18.1 versions prior to 18.1R3-S9 on PTX1000 and PTX10000 Series, QFX10000 Series; 18.2X75 versions prior to 18.2X75-D12, 18.2X75-D30 on PTX1000 and PTX10000 Series, QFX10000 Series; 18.2 versions prior to 18.2R3 on PTX1000 and PTX10000 Series, QFX10000 Series; 18.3 versions prior to 18.3R3 on PTX1000 and PTX10000 Series, QFX10000 Series. This issue is not applicable to Junos OS versions before 17.4R1. This issue is not applicable to Junos OS Evolved or Junos OS with Advanced Forwarding Toolkit (AFT) forwarding implementations which use a different implementation of sFlow. The following example information is unrelated to this issue and is provided solely to assist you with determining if you have AFT or not. Example: A Junos OS device which supports the use of EVPN signaled VPWS with Flexible Cross Connect uses the AFT implementation. Since this configuration requires support and use of the AFT implementation to support this configuration, the device is not vulnerable to this issue as the sFlow implementation is different using the AFT architecture. For further details about AFT visit the AFI / AFT are in the links below. If you are uncertain if you use the AFI/AFT implementation or not, there are configuration examples in the links below which you may use to determine if you are vulnerable to this issue or not. If the commands work, you are. If not, you are not. You may also use the Feature Explorer to determine if AFI/AFT is supported or not. If you are still uncertain, please contact your support resources. ### What kind of flaw is it? - CWE-665: Improper Initialization ### 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 take it offline Severity vector: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H` ## Is CVE-2020-1617 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 - 8 April 2020: Published - 5 February 2021: Record last updated ### How Precursor Intelligence ranks it CVE-2020-1617 scores **48 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-2020-1617? The published record lists 12 products. - [Junos](https://www.precursorintelligence.com/product/juniper/junos) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Operating system): 17.4, 17.4-r1, 17.4-r1-s1, 17.4-r1-s2, 17.4-r1-s4, 17.4-r1-s5, 17.4-r1-s6, 17.4-r1-s7, 17.4-r2, 17.4-r2-s1, 17.4-r2-s2, 17.4-r2-s3, 17.4-r2-s4, 17.4-r2-s5, 17.4-r2-s6, 17.4-r2-s7, 17.4-r2-s8, 18.1, 18.1-r2, 18.1-r2-s1, 18.1-r2-s2, 18.1-r2-s4, 18.1-r3, 18.1-r3-s1, 18.1-r3-s2, 18.1-r3-s3, 18.1-r3-s4, 18.1-r3-s6, 18.1-r3-s7, 18.1-r3-s8, 18.2, 18.2-r1, 18.2-r1-s3, 18.2-r1-s5, 18.2-r2-s1, 18.2-r2-s2, 18.2-r2-s3, 18.2-r2-s4, 18.2-r2-s5, 18.2-r2-s6 and 11 more - [Ptx1000](https://www.precursorintelligence.com/product/juniper/ptx1000) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified - [Ptx10000](https://www.precursorintelligence.com/product/juniper/ptx10000) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified - [Ptx10001](https://www.precursorintelligence.com/product/juniper/ptx10001) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified - [Ptx10002](https://www.precursorintelligence.com/product/juniper/ptx10002) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified - [Ptx10003](https://www.precursorintelligence.com/product/juniper/ptx10003) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified - [Ptx10008](https://www.precursorintelligence.com/product/juniper/ptx10008) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified - [Ptx10016](https://www.precursorintelligence.com/product/juniper/ptx10016) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified - [Ptx3000](https://www.precursorintelligence.com/product/juniper/ptx3000) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified - [Ptx5000](https://www.precursorintelligence.com/product/juniper/ptx5000) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified - [Qfx10008](https://www.precursorintelligence.com/product/juniper/qfx10008) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified - [Qfx10016](https://www.precursorintelligence.com/product/juniper/qfx10016) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified ## How do I fix CVE-2020-1617? 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 advisories and patch notes 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 - [kb.juniper.net](https://kb.juniper.net/JSA11000) (Vendor advisory) - [juniper.net](https://www.juniper.net/documentation/en_US/junos/topics/example/example-configuring-vpws-service-with-evpn-signaling-mechanisms.html) (Vendor advisory) - [github.com](https://github.com/Juniper/AFI) (Third-party advisory) ## Questions ### What is CVE-2020-1617? CVE-2020-1617 is a high-severity flaw in Junos from Juniper, published on 8 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 take it offline. ### How serious is CVE-2020-1617? It scores 7.5 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2020-1617 is 48 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. ### Is CVE-2020-1617 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-2020-1617 affect? For Junos from Juniper: 17.4, 17.4-r1, 17.4-r1-s1, 17.4-r1-s2, 17.4-r1-s4, 17.4-r1-s5 and 45 more. The record lists 12 products in all, each with its versions, under "Who is affected" on this page. ### How do I fix CVE-2020-1617? 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-2020-1617 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