CVE-2019-1842 : A vulnerability in the Secure Shell (SSH) authentication function of Cisco IOS X

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.

Published 2019-06-05 17:29:00

Updated 2020-10-16 15:41:45

Source Cisco Systems, Inc.

View at NVD, CVE.org

Vulnerability category: BypassGain privilege

Products affected by CVE-2019-1842

Cisco » Ios Xr Firmware » Version: 6.1.2.tools
cpe:2.3:o:cisco:ios_xr_firmware:6.1.2.tools:*:*:*:*:*:*:*
Matching versions
When used together with: Cisco » Asr 9001 » Version: N/A
When used together with: Cisco » Asr 9006 » Version: N/A
When used together with: Cisco » Asr 9010 » Version: N/A
When used together with: Cisco » Asr 9901 » Version: N/A
When used together with: Cisco » Asr 9904 » Version: N/A
When used together with: Cisco » Asr 9906 » Version: N/A
When used together with: Cisco » Asr 9910 » Version: N/A
When used together with: Cisco » Asr 9912 » Version: N/A
When used together with: Cisco » Asr 9922 » Version: N/A
When used together with: Cisco » Crs-1 16-slot Line Card Chassis » Version: N/A
When used together with: Cisco » Crs-1 16-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-1 4-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-1 8-slot Line Card Chassis » Version: N/A
When used together with: Cisco » Crs-1 8-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-1 Fabric Card Chassis » Version: N/A
When used together with: Cisco » Crs-1 Line Card Chassis (dual) » Version: N/A
When used together with: Cisco » Crs-1 Line Card Chassis (multi) » Version: N/A
When used together with: Cisco » Crs-1 Multishelf System » Version: N/A
When used together with: Cisco » Crs-3 16-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-3 4-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-3 8-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-3 Multishelf System » Version: N/A
When used together with: Cisco » Crs-8/s-b Crs » Version: N/A
When used together with: Cisco » Crs-8/scrs » Version: N/A
When used together with: Cisco » Crs-x 16-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-x Multishelf System » Version: N/A
When used together with: Cisco » Ncs 6008-8-slot Chassis » Version: N/A
When used together with: Cisco » Network Convergence System 5508 » Version: N/A
Cisco » Ios Xr Firmware » Version: 6.1.3.tools
cpe:2.3:o:cisco:ios_xr_firmware:6.1.3.tools:*:*:*:*:*:*:*
Matching versions
When used together with: Cisco » Asr 9001 » Version: N/A
When used together with: Cisco » Asr 9006 » Version: N/A
When used together with: Cisco » Asr 9010 » Version: N/A
When used together with: Cisco » Asr 9901 » Version: N/A
When used together with: Cisco » Asr 9904 » Version: N/A
When used together with: Cisco » Asr 9906 » Version: N/A
When used together with: Cisco » Asr 9910 » Version: N/A
When used together with: Cisco » Asr 9912 » Version: N/A
When used together with: Cisco » Asr 9922 » Version: N/A
When used together with: Cisco » Crs-1 16-slot Line Card Chassis » Version: N/A
When used together with: Cisco » Crs-1 16-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-1 4-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-1 8-slot Line Card Chassis » Version: N/A
When used together with: Cisco » Crs-1 8-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-1 Fabric Card Chassis » Version: N/A
When used together with: Cisco » Crs-1 Line Card Chassis (dual) » Version: N/A
When used together with: Cisco » Crs-1 Line Card Chassis (multi) » Version: N/A
When used together with: Cisco » Crs-1 Multishelf System » Version: N/A
When used together with: Cisco » Crs-3 16-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-3 4-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-3 8-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-3 Multishelf System » Version: N/A
When used together with: Cisco » Crs-8/s-b Crs » Version: N/A
When used together with: Cisco » Crs-8/scrs » Version: N/A
When used together with: Cisco » Crs-x 16-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-x Multishelf System » Version: N/A
When used together with: Cisco » Ncs 6008-8-slot Chassis » Version: N/A
When used together with: Cisco » Network Convergence System 5508 » Version: N/A
Cisco » Ios Xr Firmware » Version: 6.2.3.tools
cpe:2.3:o:cisco:ios_xr_firmware:6.2.3.tools:*:*:*:*:*:*:*
Matching versions
When used together with: Cisco » Asr 9001 » Version: N/A
When used together with: Cisco » Asr 9006 » Version: N/A
When used together with: Cisco » Asr 9010 » Version: N/A
When used together with: Cisco » Asr 9901 » Version: N/A
When used together with: Cisco » Asr 9904 » Version: N/A
When used together with: Cisco » Asr 9906 » Version: N/A
When used together with: Cisco » Asr 9910 » Version: N/A
When used together with: Cisco » Asr 9912 » Version: N/A
When used together with: Cisco » Asr 9922 » Version: N/A
When used together with: Cisco » Crs-1 16-slot Line Card Chassis » Version: N/A
When used together with: Cisco » Crs-1 16-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-1 4-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-1 8-slot Line Card Chassis » Version: N/A
When used together with: Cisco » Crs-1 8-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-1 Fabric Card Chassis » Version: N/A
When used together with: Cisco » Crs-1 Line Card Chassis (dual) » Version: N/A
When used together with: Cisco » Crs-1 Line Card Chassis (multi) » Version: N/A
When used together with: Cisco » Crs-1 Multishelf System » Version: N/A
When used together with: Cisco » Crs-3 16-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-3 4-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-3 8-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-3 Multishelf System » Version: N/A
When used together with: Cisco » Crs-8/s-b Crs » Version: N/A
When used together with: Cisco » Crs-8/scrs » Version: N/A
When used together with: Cisco » Crs-x 16-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-x Multishelf System » Version: N/A
When used together with: Cisco » Ncs 6008-8-slot Chassis » Version: N/A
When used together with: Cisco » Network Convergence System 5508 » Version: N/A
Cisco » Ios Xr Firmware » Version: 6.4.2.tools
cpe:2.3:o:cisco:ios_xr_firmware:6.4.2.tools:*:*:*:*:*:*:*
Matching versions
When used together with: Cisco » Asr 9001 » Version: N/A
When used together with: Cisco » Asr 9006 » Version: N/A
When used together with: Cisco » Asr 9010 » Version: N/A
When used together with: Cisco » Asr 9901 » Version: N/A
When used together with: Cisco » Asr 9904 » Version: N/A
When used together with: Cisco » Asr 9906 » Version: N/A
When used together with: Cisco » Asr 9910 » Version: N/A
When used together with: Cisco » Asr 9912 » Version: N/A
When used together with: Cisco » Asr 9922 » Version: N/A
When used together with: Cisco » Crs-1 16-slot Line Card Chassis » Version: N/A
When used together with: Cisco » Crs-1 16-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-1 4-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-1 8-slot Line Card Chassis » Version: N/A
When used together with: Cisco » Crs-1 8-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-1 Fabric Card Chassis » Version: N/A
When used together with: Cisco » Crs-1 Line Card Chassis (dual) » Version: N/A
When used together with: Cisco » Crs-1 Line Card Chassis (multi) » Version: N/A
When used together with: Cisco » Crs-1 Multishelf System » Version: N/A
When used together with: Cisco » Crs-3 16-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-3 4-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-3 8-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-3 Multishelf System » Version: N/A
When used together with: Cisco » Crs-8/s-b Crs » Version: N/A
When used together with: Cisco » Crs-8/scrs » Version: N/A
When used together with: Cisco » Crs-x 16-slot Single-shelf System » Version: N/A
When used together with: Cisco » Crs-x Multishelf System » Version: N/A
When used together with: Cisco » Ncs 6008-8-slot Chassis » Version: N/A
When used together with: Cisco » Network Convergence System 5508 » Version: N/A

Exploit prediction scoring system (EPSS) score for CVE-2019-1842

EPSS FAQ

0.27%

Probability of exploitation activity in the next 30 days EPSS Score History

~ 47 %

Percentile, the proportion of vulnerabilities that are scored at or less

CVSS scores for CVE-2019-1842

Base Score	Base Severity	CVSS Vector	Exploitability Score	Impact Score	Score Source
5.5	MEDIUM	AV:N/AC:L/Au:S/C:P/I:P/A:N	8.0	4.9	NIST
Access Vector: Network Access Complexity: Low Authentication: Single Confidentiality Impact: Partial Integrity Impact: Partial Availability Impact: None
5.4	MEDIUM	CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N	2.8	2.5	Cisco Systems, Inc.
Attack Vector: Network Attack Complexity: Low Privileges Required: Low User Interaction: None Scope: Unchanged Confidentiality: Low Integrity: Low Availability: None
5.4	MEDIUM	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N	2.8	2.5	NIST
Attack Vector: Network Attack Complexity: Low Privileges Required: Low User Interaction: None Scope: Unchanged Confidentiality: Low Integrity: Low Availability: None

CWE ids for CVE-2019-1842

CWE-285 Improper Authorization

The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action.

Assigned by: ykramarz@cisco.com (Secondary)
CWE-287 Improper Authentication

When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.

Assigned by: nvd@nist.gov (Primary)

References for CVE-2019-1842

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190605-iosxr-ssh

Cisco IOS XR Software Secure Shell Authentication Vulnerability
Vendor Advisory
http://www.securityfocus.com/bid/108687

Cisco IOS XR Software CVE-2019-1842 Unauthorized Access Vulnerability
Third Party Advisory;VDB Entry

Jump to

Vulnerability Details : CVE-2019-1842

Products affected by CVE-2019-1842

Exploit prediction scoring system (EPSS) score for CVE-2019-1842

CVSS scores for CVE-2019-1842

CWE ids for CVE-2019-1842

References for CVE-2019-1842