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Identity Services EngineApplication · Cisco

CVE-2017-6747

CRITICAL · 9.8 CVSS v3.0 Published 2017-08-07
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A vulnerability in the authentication module of Cisco Identity Services Engine (ISE) could allow an unauthenticated, remote attacker to bypass local authentication. The vulnerability is due to improper handling of authentication requests and policy assignment for externally authenticated users. An attacker could exploit this vulnerability by authenticating with a valid external user account that matches an internal username and incorrectly receiving the authorization policy of the internal account. An exploit could allow the attacker to have Super Admin privileges for the ISE Admin portal. This vulnerability does not affect endpoints authenticating to the ISE. The vulnerability affects Cisco ISE, Cisco ISE Express, and Cisco ISE Virtual Appliance running Release 1.3, 1.4, 2.0.0, 2.0.1, or 2.1.0. Release 2.2.x is not affected. Cisco Bug IDs: CSCvb10995.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A vulnerability in the Cisco ISE authentication module allows an unauthenticated remote attacker to bypass local authentication by exploiting improper handling of authentication requests for externally authenticated users. When an external user account matches an internal username, the attacker incorrectly receives the internal account's authorization policy, potentially granting Super Admin privileges to the ISE Admin portal.

MitigationUpgrade Cisco ISE to release 2.2.x or later, which is not affected by this vulnerability. Prior to upgrade, back up configurations and test in a staging environment.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Identity Services EngineApplication
Affected:= 1.3\(0.722\)= 1.3\(0.876\)= 1.3\(0.909\)= 1.3\(106.146\)= 1.3\(120.135\)= 1.4\(0.109\)= 1.4\(0.181\)= 1.4\(0.253\)= 1.4\(0.908\)= 2.0\(0.147\)= 2.0\(0.169\)= 2.0\(0.222\)

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check Cisco ISE version
    Log into the ISE Admin portal and navigate to Administration > System > Deployment. Verify the ISE version shown in the deployment node details, or run 'show version' command via CLI.
    Affected if The installed version matches any of the following: 1.3(0.722), 1.3(0.876), 1.3(0.909), 1.3(106.146), 1.3(120.135), 1.4(0.109), 1.4(0.181), 1.4(0.253), 1.4(0.908), 2.0(0.147), 2.0(0.169), 2.0(0.222)
  2. Verify external identity source configuration
    Navigate to Administration > Identity Management > External Identity Sources in the ISE Admin portal. Check if any external identity sources such as Active Directory, LDAP, or RADIUS are configured and enabled.
    Affected if External identity sources are configured and connected to ISE, allowing external users to authenticate
  3. Identify internal usernames that match external identities
    Review external identity source groups and user accounts. Compare these against internal admin usernames in Administration > Identity Management > Users to identify any username overlaps.
    Affected if An external user identity shares the same username as an internal ISE admin account
  4. Review external user authorization policies
    Go to Policy > Policy Sets and examine authorization policies that apply to externally authenticated users. Check whether these policies grant elevated privileges such as Super Admin or admin access.
    Affected if Authorization policies for external users grant Super Admin or high-privilege access that could be exploited through the username match

You are affected if your Cisco ISE version matches the vulnerable versions AND external identity sources are configured with usernames that overlap internal admin accounts.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade Cisco ISE to release 2.2.x or later, which is not affected by this vulnerability. Prior to upgrade, back up configurations and test in a staging environment.

Recommended fix Moderate confidence

Cisco ISE Release 2.2.0 or later (2.2.x, 2.3.x, 2.4.x, etc.)

  1. 1. Identify the current Cisco ISE version by navigating to the ISE admin GUI and checking the Dashboard or by running 'show version' in the CLI
  2. 2. Confirm the current version is one of the affected releases: 1.3(x), 1.4, 2.0.0, 2.0.1, or 2.1.0
  3. 3. Schedule a maintenance window for the upgrade process
  4. 4. Back up the ISE configuration using the admin GUI (Administration > System > Backup & Restore) or CLI backup command
  5. 5. Download the fixed release (2.2.0 or later) from Cisco.com software downloads
  6. 6. Upgrade the ISE nodes in the deployment, starting with the primary node and then secondary nodes, following Cisco's standard upgrade documentation
  7. 7. After upgrade, verify the version change and test authentication functionality
  8. 8. Confirm the vulnerability is remediated by verifying external user authentication no longer incorrectly inherits internal user authorization policies
Caveat Standard ISE upgrade considerations apply - review Cisco ISE upgrade guide for compatibility requirements, ensure sufficient disk space, and plan for potential certificate re-enrollment if moving between major version families

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Identity Services Engine Scoped from the published advisory
  • Consultation8.0 h
  • Implementation8.0 h
  • Testing8.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,960
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2017-6747 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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