CVE-2019-1836 : A vulnerability in the system shell for Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (A

A vulnerability in the system shell for Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) mode could allow an authenticated, local attacker to use symbolic links to overwrite system files. These system files may be sensitive and should not be overwritable by non-root users. The attacker would need valid device credentials. The vulnerability is due to incorrect symbolic link verification of directory paths when they are used in the system shell. An attacker could exploit this vulnerability by authenticating to the device and providing crafted user input to specific symbolic link CLI commands. Successful exploitation could allow the attacker to overwrite system files that should be restricted. This vulnerability has been fixed in software version 14.1(1i).

Published 2019-05-03 17:29:01

Updated 2020-10-13 20:27:27

Source Cisco Systems, Inc.

View at NVD, CVE.org

Vulnerability category: Directory traversal

Exploit prediction scoring system (EPSS) score for CVE-2019-1836

EPSS FAQ

0.04%

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

~ 8 %

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

CVSS scores for CVE-2019-1836

Base Score	Base Severity	CVSS Vector	Exploitability Score	Impact Score	Score Source
6.6	MEDIUM	AV:L/AC:L/Au:N/C:N/I:C/A:C	3.9	9.2	NIST
Access Vector: Local Access Complexity: Low Authentication: None Confidentiality Impact: None Integrity Impact: Complete Availability Impact: Complete
5.5	MEDIUM	CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N	1.8	3.6	Cisco Systems, Inc.
Attack Vector: Local Attack Complexity: Low Privileges Required: Low User Interaction: None Scope: Unchanged Confidentiality: None Integrity: High Availability: None
7.1	HIGH	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H	1.8	5.2	NIST
Attack Vector: Local Attack Complexity: Low Privileges Required: Low User Interaction: None Scope: Unchanged Confidentiality: None Integrity: High Availability: High

CWE ids for CVE-2019-1836

CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

Assigned by: ykramarz@cisco.com (Secondary)

CWE-59 Improper Link Resolution Before File Access ('Link Following')

The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

Assigned by: nvd@nist.gov (Primary)

References for CVE-2019-1836

http://www.securityfocus.com/bid/108150

Cisco Nexus 9000 Series Fabric Switches Path Traversal Arbitrary File Write Vulnerability
Third Party Advisory;VDB Entry
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190501-fabric-traversal

Cisco Nexus 9000 Series Fabric Switches Application Centric Infrastructure Mode Symbolic Link Path Traversal Vulnerability
Vendor Advisory

Products affected by CVE-2019-1836

Cisco » Nx-os » Version: 14.0(3d)
cpe:2.3:o:cisco:nx-os:14.0\(3d\):*:*:*:*:*:*:*
Matching versions
When used together with: Cisco » Nexus 9300 » Version: N/A
When used together with: Cisco » Nexus 9500 » Version: N/A

Vulnerability Details : CVE-2019-1836

Exploit prediction scoring system (EPSS) score for CVE-2019-1836

CVSS scores for CVE-2019-1836

CWE ids for CVE-2019-1836

References for CVE-2019-1836

Products affected by CVE-2019-1836