dbcve.org
Asr 5000 SoftwareApplication · Cisco

CVE-2017-6773

MEDIUM · 6.7 CVSS v3.0 Published 2017-08-17
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
69/100
Remediation priority · Elevated
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 CLI of Cisco ASR 5000 Series Aggregated Services Routers running the Cisco StarOS operating system could allow an authenticated, local attacker to bypass the CLI restrictions and execute commands on the underlying operating system. The vulnerability is due to insufficient input sanitization of user-supplied input at the CLI. An attacker could exploit this vulnerability by crafting a script on the device that will allow them to bypass built-in restrictions. An exploit could allow the unauthorized user to launch the CLI directly from a command shell. Cisco Bug IDs: CSCvd47722. Known Affected Releases: 21.0.v0.65839.

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

CVE-2017-6773 is a local authenticated CLI restriction bypass vulnerability in Cisco ASR 5000 Series routers running StarOS. The flaw stems from insufficient input sanitization in the CLI interface, allowing an authenticated attacker to craft scripts that bypass built-in restrictions and launch the CLI directly from the underlying command shell, executing arbitrary OS-level commands.

MitigationApply the Cisco patch for bug CSCvd47722 by upgrading to a fixed StarOS release. Until patched, limit CLI access to trusted administrators and monitor for suspicious shell access patterns.

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
Asr 5000 SoftwareApplication
Affected:= 21.0.v0.65839

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
Local
Complexity
Low
Privileges
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:L/AC:L/PR:H/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. Identify the StarOS version running on the ASR 5000
    Access the router CLI and run the command: show version OR show software. This displays the installed StarOS version and build number.
    Affected if The displayed version matches exactly 21.0.v0.65839, indicating the specific affected build.
  2. Confirm the platform is an ASR 5000 Series router
    Run the command: show hardware. This identifies the router model and confirms it is an ASR 5000 Series device running StarOS.
    Affected if The hardware shows ASR 5000 Series and the software is StarOS - only this platform and software combination is affected.
  3. Review CLI session logs for shell invocation patterns
    Run the command: show logs | grep -i shell OR show logs | grep "cli" to examine recent CLI activity logs. Look for entries indicating CLI was launched from the underlying shell rather than the normal restricted CLI session.
    Affected if Logs show CLI sessions spawned directly from the underlying shell prompt (such as entries containing 'sh' or '/CLI' launched from bash/sh) rather than normal restricted CLI entry points.
  4. Audit administrator accounts for suspicious activity
    Run the command: show admin users OR show logged-in users to list current and recent administrator sessions. Correlate session times with any detected shell-access anomalies.
    Affected if Administrative accounts show sessions originating from unexpected source contexts or containing unusually long session durations that could indicate escaped CLI sessions.
  5. Check for unauthorized CLI command execution at the OS level
    If you have access to the underlying shell (not the StarOS CLI), run: last | grep tty OR examine /var/log/messages for any CLI-related processes spawned from shell contexts. On the StarOS CLI, run: show process facility cli-manager for any anomalies.
    Affected if Process logs or system logs show CLI manager processes spawned from the underlying shell environment rather than through the normal restricted CLI login pathway.

You are affected if your ASR 5000 router runs StarOS version exactly 21.0.v0.65839, or if logs show CLI sessions bypassing normal restricted entry points and executing from the underlying shell environment.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the Cisco patch for bug CSCvd47722 by upgrading to a fixed StarOS release. Until patched, limit CLI access to trusted administrators and monitor for suspicious shell access patterns.

Fix this in Asr 5000 Software Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2017-6773 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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