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AUSCERT External Security Bulletin Redistribution
Cisco IOS XE Software REST API Authorization Bypass Vulnerability
29 March 2018
AusCERT Security Bulletin Summary
Product: Cisco IOS XE
Publisher: Cisco Systems
Operating System: Cisco
Impact/Access: Unauthorised Access -- Existing Account
CVE Names: CVE-2018-0195
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Cisco Security Advisory
Cisco IOS XE Software REST API Authorization Bypass Vulnerability
Advisory ID: cisco-sa-20180328-rest
FirstÂ Published: 2018Â MarchÂ 28Â 16:00Â GMT
VersionÂ 1.0: Final
Workarounds: No workarounds available
Cisco Bug IDs:
o A vulnerability in the Cisco IOS XE Software REST API could allow an
authenticated, remote attacker to bypass API authorization checks and use
the API to perform privileged actions on an affected device.
The vulnerability is due to insufficient authorization checks for requests
that are sent to the REST API of the affected software. An attacker could
exploit this vulnerability by sending a malicious request to an affected
device via the REST API. A successful exploit could allow the attacker to
selectively bypass authorization checks for the REST API of the affected
software and use the API to perform privileged actions on an affected
There are no workarounds that address this vulnerability.
This advisory is available at the following link:
o Vulnerable Products
This vulnerability affects Cisco devices that are running a vulnerable
release of Cisco IOS XE Software and are configured to support use of the
Cisco IOS XE Software REST API for device management.
For information about which Cisco IOS XE Software releases are vulnerable,
consult the Cisco bug ID(s) at the top of this advisory.
Determining the Cisco IOS XE Software Release
To determine which Cisco IOS XE Software release is running on a device,
administrators can log in to the device, use the show version command in
the CLI, and then refer to the system banner that appears. If the device is
running Cisco IOS XE Software, the system banner displays Cisco IOS
Software, Cisco IOS XE Software, or similar text.
The following example shows the output of the command for a device that is
running Cisco IOS XE Software Release 16.2.1 and has an installed image
name of CAT3K_CAA-UNIVERSALK9-M:
ios-xe-device# show version
Cisco IOS Software, Catalyst L3 Switch Software (CAT3K_CAA-UNIVERSALK9-M), Version Denali 16.2.1, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2016 by Cisco Systems, Inc.
Compiled Sun 27-Mar-16 21:47 by mcpre
For information about the naming and numbering conventions for Cisco IOS XE
Software releases, see the Cisco IOS and NX-OS Software Reference Guide.
Products Confirmed Not Vulnerable
No other Cisco products are currently known to be affected by this
Cisco has confirmed that this vulnerability does not affect Cisco IOS
Software, Cisco IOS XR Software, or Cisco NX-OS Software.
o There are no workarounds that address this vulnerability.
o For detailed information about fixed software releases, consult the Cisco
bug ID(s) at the top of this advisory.
For a mapping of Cisco IOS XE Software releases to Cisco IOS Software
releases, refer to the Cisco IOS XE 2 Release Notes, Cisco IOS XE 3S
Release Notes, or Cisco IOS XE 3SG Release Notes, depending on the
Cisco IOS XE Software release.
When considering software upgrades, customers are advised to regularly
consult the advisories for Cisco products, which are available from the
Cisco Security Advisories and Alerts page, to determine exposure and a
complete upgrade solution.
In all cases, customers should ensure that the devices to be upgraded
contain sufficient memory and confirm that current hardware and software
configurations will continue to be supported properly by the new release.
If the information is not clear, customers are advised to contact the Cisco
Technical Assistance Center (TAC) or their contracted maintenance
Exploitation and Public Announcements
o The Cisco Product Security Incident Response Team (PSIRT) is not aware of
any public announcements or malicious use of the vulnerability that is
described in this advisory.
o This vulnerability was found during internal security testing.
Cisco Security Vulnerability Policy
o To learn about Cisco security vulnerability disclosure policies and
publications, see the Security Vulnerability Policy. This document also
contains instructions for obtaining fixed software and receiving security
vulnerability information from Cisco.
Subscribe to Cisco Security Notifications
| Version | Description | Section | Status | Date |
| 1.0 | Initial public release. | -- | Final | 2018-March-28 |
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