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Remote Expert ManagerApplication · Cisco

CVE-2017-6641

HIGH · 7.5 CVSS v3.0 Published 2017-05-22
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
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 TCP connection handling functionality of Cisco Remote Expert Manager Software 11.0.0 could allow an unauthenticated, remote attacker to disable TCP ports and cause a denial of service (DoS) condition on an affected system. The vulnerability is due to a lack of rate-limiting functionality in the TCP Listen application of the affected software. An attacker could exploit this vulnerability by sending a crafted TCP traffic stream in which specific types of TCP packets are flooded to an affected device, for example a TCP packet stream in which the TCP FIN bit is set in all the TCP packets. A successful exploit could allow the attacker to cause certain TCP listening ports on the affected system to stop accepting incoming connections for a period of time or until the affected device is restarted, resulting in a DoS condition. In addition, system resources, such as CPU and memory, could be exhausted during the attack. Cisco Bug IDs: CSCva29806.

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 Cisco Remote Expert Manager Software 11.0.0 allows unauthenticated remote attackers to cause a DoS by flooding the TCP Listen application with crafted TCP packets (e.g., packets with FIN bit set). The lack of rate-limiting enables the attack to exhaust CPU and memory resources, causing TCP listening ports to stop accepting connections until the device is restarted.

MitigationApply the Cisco patch for bug ID CSCva29806, or implement upstream network filtering/rate-limiting to block excessive TCP packets with anomalous flag combinations.

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
Remote Expert ManagerApplication
Affected:= 11.0.0

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
None
Integrity
None
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 installed Cisco Remote Expert Manager version
    Locate the installed version of Cisco Remote Expert Manager software on the system. Use the system's software inventory, version display command, or check the application binaries for the exact version number.
    Affected if The installed version is exactly 11.0.0.
  2. Verify TCP Listen application is running
    Identify processes or services corresponding to the TCP Listen application within Cisco Remote Expert Manager. Check running processes or service status to confirm the application is active.
    Affected if The TCP Listen application is running and exposed to network access.
  3. Check for listening TCP ports
    Use netstat, ss, or equivalent command to list all TCP ports in LISTEN state provided by the Cisco Remote Expert Manager application. Note the port numbers and their status.
    Affected if TCP listening ports are in LISTEN state and accessible from the network.
  4. Test port responsiveness
    Attempt TCP connections to the listening ports identified in the previous step using a tool like telnet, nc, or ncat. Observe whether connections are accepted or rejected.
    Affected if Connections are refused or ports appear unresponsive, indicating the DoS condition may be present.
  5. Check system resource consumption
    Monitor CPU and memory usage on the device running Cisco Remote Expert Manager. Look for unusually high resource consumption that could indicate the resource exhaustion described in the CVE.
    Affected if CPU and memory resources are abnormally high or exhausted, particularly if the TCP Listen application is consuming excessive resources.

A system is affected if it is running Cisco Remote Expert Manager version 11.0.0 with the TCP Listen application accessible over the network and symptoms of port unresponsiveness or resource exhaustion are observed.

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 ID CSCva29806, or implement upstream network filtering/rate-limiting to block excessive TCP packets with anomalous flag combinations.

Fix this in Remote Expert Manager Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,120
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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-2017-6641 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data