# What is CVE-2019-1842? > CVE-2019-1842 is a medium-severity flaw (CVSS 5.4) in Ios XR Firmware from Cisco, published on 5 June 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 1.2%. If you run an affected version, plan in the vendor’s fix. Canonical page: https://www.precursorintelligence.com/what-is/cve-2019-1842 ## 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:** 20 out of 100 (Low); action: Monitor. Kept up to date as the evidence changes. - **Severity:** Medium (CVSS 5.4 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:** 1.2% (latest exploit-likelihood forecast) - **Published:** 5 June 2019 - **Record last updated:** 16 October 2020 - **Main product:** Ios XR Firmware from Cisco - **Affected products:** 29 ## What is CVE-2019-1842? In plain terms It can be attacked from anywhere on the internet with an ordinary user account, and nobody has to click anything. If it works, the attacker can read some data and change some data. ### The official description A vulnerability in the Secure Shell (SSH) authentication function of Cisco IOS XR Software could allow an authenticated, remote attacker to successfully log in to an affected device using two distinct usernames. The vulnerability is due to a logic error that may occur when certain sequences of actions are processed during an SSH login event on the affected device. An attacker could exploit this vulnerability by initiating an SSH session to the device with a specific sequence that presents the two usernames. A successful exploit could result in logging data misrepresentation, user enumeration, or, in certain circumstances, a command authorization bypass. See the Details section for more information. ### What kind of flaw is it? - CWE-287: Improper Authentication - CWE-285: Improper Authorization ### 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: An ordinary user account - Does someone have to click: No, nobody has to do anything - What an attacker gets: Can read some data and change some data Severity vector: `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N` ## Is CVE-2019-1842 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 1.2%. That can change at any time, which is why we keep watching. Exploit likelihood over the last 7 days: 1.2%, 1.2%, 1.2%, 1.2%, 1.2%, 1.2%, 1.2%. ### Timeline - 5 June 2019: Published - 16 October 2020: Record last updated ### How Precursor Intelligence ranks it CVE-2019-1842 scores **20 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: key context - Real threat activity around it: key context 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-2019-1842? The published record lists 29 products. - [Ios XR Firmware](https://www.precursorintelligence.com/product/cisco/ios_xr_firmware) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Operating system): 6.1.2.tools, 6.1.3.tools, 6.2.3.tools, 6.4.2.tools - [ASR 9001](https://www.precursorintelligence.com/product/cisco/asr_9001) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [ASR 9006](https://www.precursorintelligence.com/product/cisco/asr_9006) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [ASR 9010](https://www.precursorintelligence.com/product/cisco/asr_9010) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [ASR 9901](https://www.precursorintelligence.com/product/cisco/asr_9901) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [ASR 9904](https://www.precursorintelligence.com/product/cisco/asr_9904) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [ASR 9906](https://www.precursorintelligence.com/product/cisco/asr_9906) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [ASR 9910](https://www.precursorintelligence.com/product/cisco/asr_9910) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [ASR 9912](https://www.precursorintelligence.com/product/cisco/asr_9912) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [ASR 9922](https://www.precursorintelligence.com/product/cisco/asr_9922) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Crs-1 16-Slot Line Card Chassis](https://www.precursorintelligence.com/product/cisco/crs-1_16-slot_line_card_chassis) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Crs-1 16-Slot Single-Shelf System](https://www.precursorintelligence.com/product/cisco/crs-1_16-slot_single-shelf_system) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Crs-1 4-Slot Single-Shelf System](https://www.precursorintelligence.com/product/cisco/crs-1_4-slot_single-shelf_system) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Crs-1 8-Slot Line Card Chassis](https://www.precursorintelligence.com/product/cisco/crs-1_8-slot_line_card_chassis) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Crs-1 8-Slot Single-Shelf System](https://www.precursorintelligence.com/product/cisco/crs-1_8-slot_single-shelf_system) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Crs-1 Fabric Card Chassis](https://www.precursorintelligence.com/product/cisco/crs-1_fabric_card_chassis) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - Crs-1 Line Card Chassis (dual) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - Crs-1 Line Card Chassis (multi) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Crs-1 Multishelf System](https://www.precursorintelligence.com/product/cisco/crs-1_multishelf_system) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Crs-3 16-Slot Single-Shelf System](https://www.precursorintelligence.com/product/cisco/crs-3_16-slot_single-shelf_system) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Crs-3 4-Slot Single-Shelf System](https://www.precursorintelligence.com/product/cisco/crs-3_4-slot_single-shelf_system) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Crs-3 8-Slot Single-Shelf System](https://www.precursorintelligence.com/product/cisco/crs-3_8-slot_single-shelf_system) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Crs-3 Multishelf System](https://www.precursorintelligence.com/product/cisco/crs-3_multishelf_system) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - Crs-8/s-B Crs by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - Crs-8/scrs by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Crs-X 16-Slot Single-Shelf System](https://www.precursorintelligence.com/product/cisco/crs-x_16-slot_single-shelf_system) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Crs-X Multishelf System](https://www.precursorintelligence.com/product/cisco/crs-x_multishelf_system) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Ncs 6008-8-Slot Chassis](https://www.precursorintelligence.com/product/cisco/ncs_6008-8-slot_chassis) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Network Convergence System 5508](https://www.precursorintelligence.com/product/cisco/network_convergence_system_5508) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified ## How do I fix CVE-2019-1842? 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-20190605-iosxr-ssh) (Vendor advisory) - [securityfocus.com](http://www.securityfocus.com/bid/108687) (Third-party advisory, Vulnerability database) ## Questions ### What is CVE-2019-1842? CVE-2019-1842 is a medium-severity flaw in Ios XR Firmware from Cisco, published on 5 June 2019. It can be attacked from anywhere on the internet with an ordinary user account, and nobody has to click anything. If it works, the attacker can read some data and change some data. ### How serious is CVE-2019-1842? It scores 5.4 out of 10 on the CVSS severity scale, which is medium. Our risk score for CVE-2019-1842 is 20 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-2019-1842 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 1.2%. That can change at any time, which is why we keep watching. ### Which versions does CVE-2019-1842 affect? For Ios XR Firmware from Cisco: 6.1.2.tools, 6.1.3.tools, 6.2.3.tools, 6.4.2.tools. The record lists 29 products in all, each with its versions, under "Who is affected" on this page. ### How do I fix CVE-2019-1842? 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-2019-1842 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