# What is CVE-2019-18336? > CVE-2019-18336 is a high-severity flaw (CVSS 7.5) in Simatic S7-300 CPU from Siemens, published on 10 March 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-2019-18336 ## 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:** 46 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:** 1.7% (latest exploit-likelihood forecast) - **Published:** 10 March 2020 - **Record last updated:** 29 September 2020 - **Main product:** Simatic S7-300 CPU from Siemens - **Affected products:** 23 ## What is CVE-2019-18336? 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 A vulnerability has been identified in SIMATIC S7-300 CPU family (incl. related ET200 CPUs and SIPLUS variants) (All versions < V3.X.17), SIMATIC TDC CP51M1 (All versions < V1.1.8), SIMATIC TDC CPU555 (All versions < V1.1.1), SINUMERIK 840D sl (All versions < V4.8.6), SINUMERIK 840D sl (All versions < V4.94). Specially crafted packets sent to port 102/tcp (Profinet) could cause the affected device to go into defect mode. A restart is required in order to recover the system. Successful exploitation requires an attacker to have network access to port 102/tcp, with no authentication. No user interation is required. At the time of advisory publication no public exploitation of this security vulnerability was known. ### What kind of flaw is it? - CWE-400: Uncontrolled Resource Consumption ### 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-2019-18336 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 - 10 March 2020: Published - 29 September 2020: Record last updated ### How Precursor Intelligence ranks it CVE-2019-18336 scores **46 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-2019-18336? The published record lists 23 products. Versions are as published: "before 4.8.6" means every version up to, but not including, 4.8.6. - [Simatic S7-300 CPU](https://www.precursorintelligence.com/product/siemens/simatic_s7-300_cpu) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Sinumerik 840d Sl](https://www.precursorintelligence.com/product/siemens/sinumerik_840d_sl) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Application): before 4.8.6, before 4.94 - [Simatic S7-300 CPU 312 Ifm](https://www.precursorintelligence.com/product/siemens/simatic_s7-300_cpu_312_ifm) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic S7-300 CPU 312 Ifm Firmware](https://www.precursorintelligence.com/product/siemens/simatic_s7-300_cpu_312_ifm_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 3.3.17 - [Simatic S7-300 CPU 313](https://www.precursorintelligence.com/product/siemens/simatic_s7-300_cpu_313) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic S7-300 CPU 313 Firmware](https://www.precursorintelligence.com/product/siemens/simatic_s7-300_cpu_313_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 3.3.17 - [Simatic S7-300 CPU 314](https://www.precursorintelligence.com/product/siemens/simatic_s7-300_cpu_314) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic S7-300 CPU 314 Firmware](https://www.precursorintelligence.com/product/siemens/simatic_s7-300_cpu_314_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 3.3.17 - [Simatic S7-300 CPU 314 Ifm](https://www.precursorintelligence.com/product/siemens/simatic_s7-300_cpu_314_ifm) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic S7-300 CPU 314 Ifm Firmware](https://www.precursorintelligence.com/product/siemens/simatic_s7-300_cpu_314_ifm_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 3.3.17 - [Simatic S7-300 CPU 315](https://www.precursorintelligence.com/product/siemens/simatic_s7-300_cpu_315) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic S7-300 CPU 315 Firmware](https://www.precursorintelligence.com/product/siemens/simatic_s7-300_cpu_315_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 3.3.17 - [Simatic S7-300 CPU 315-2 Dp](https://www.precursorintelligence.com/product/siemens/simatic_s7-300_cpu_315-2_dp) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic S7-300 CPU 315-2 Dp Firmware](https://www.precursorintelligence.com/product/siemens/simatic_s7-300_cpu_315-2_dp_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 3.3.17 - [Simatic S7-300 CPU 316-2 Dp](https://www.precursorintelligence.com/product/siemens/simatic_s7-300_cpu_316-2_dp) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic S7-300 CPU 316-2 Dp Firmware](https://www.precursorintelligence.com/product/siemens/simatic_s7-300_cpu_316-2_dp_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 3.3.17 - [Simatic S7-300 CPU 318-2](https://www.precursorintelligence.com/product/siemens/simatic_s7-300_cpu_318-2) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic S7-300 CPU 318-2 Firmware](https://www.precursorintelligence.com/product/siemens/simatic_s7-300_cpu_318-2_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 3.3.17 - [Simatic S7-300 CPU Firmware](https://www.precursorintelligence.com/product/siemens/simatic_s7-300_cpu_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 3.3.17 - [Simatic Tdc Cp51m1](https://www.precursorintelligence.com/product/siemens/simatic_tdc_cp51m1) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic Tdc Cp51m1 Firmware](https://www.precursorintelligence.com/product/siemens/simatic_tdc_cp51m1_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 1.1.8 - [Simatic Tdc Cpu555](https://www.precursorintelligence.com/product/siemens/simatic_tdc_cpu555) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic Tdc Cpu555 Firmware](https://www.precursorintelligence.com/product/siemens/simatic_tdc_cpu555_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 1.1.1 ## How do I fix CVE-2019-18336? 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 - [cert-portal.siemens.com](https://cert-portal.siemens.com/productcert/pdf/ssa-508982.pdf) (Vendor advisory) ## Questions ### What is CVE-2019-18336? CVE-2019-18336 is a high-severity flaw in Simatic S7-300 CPU from Siemens, published on 10 March 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-2019-18336? It scores 7.5 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2019-18336 is 46 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-2019-18336 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-2019-18336 affect? For Simatic S7-300 CPU from Siemens: version not specified. The record lists 23 products in all, each with its versions, under "Who is affected" on this page. ### How do I fix CVE-2019-18336? 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-2019-18336 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