CVE-2015-0666: Cisco Prime Data Center Network Manager (DCNM) Directory Traversal Vulnerability

CVE-2015-0666 is a directory traversal vulnerability in Cisco Prime Data Center Network Manager (DCNM), specifically in the fmserver servlet. It allows a remote attacker to read arbitrary files on the system hosting the product. For IT and security teams that run DCNM to manage data center networks, this matters because unauthorized file read can expose configuration, credentials, or other sensitive operational data and should be treated as a priority until the vendor fix is confirmed and applied.

Public detail is limited to the class of flaw and the affected product component. Confirm exact impact, fixed releases, and deployment notes against the Cisco advisory before acting.

How it works

This issue is classified as CWE-22 (Improper Limitation of a Pathname to a Restricted Directory). In products that accept path or filename input through a web-facing component such as a servlet, insufficient validation can let an attacker supply sequences that escape the intended directory and reach other locations on the filesystem.

According to the available summary, the flaw is in the fmserver servlet of Cisco Prime DCNM. A remote attacker who can reach that interface may craft requests that cause the application to return the contents of arbitrary files rather than only the files the servlet was meant to serve. The result is unauthorized disclosure of file contents. Specific request formats, authentication requirements, and exact file paths that can be reached are not provided here; treat any such detail as something that must be verified in the vendor advisory and your own testing in a controlled environment.

Am I affected? How to find it in your systems

Cisco Prime Data Center Network Manager is typically deployed in data center and network operations environments to manage switches, fabrics, and related infrastructure. It often runs as a management server or appliance with a web administrative interface that may be reachable from operations networks or, if mis-exposed, from broader networks.

Inventory steps:

• Identify all hosts or VMs running Cisco Prime DCNM (check asset management, CMDB, software inventory, and network management tool lists).
• Confirm the installed product version and build against the versions listed as affected in the Cisco advisory for CVE-2015-0666; do not rely on version guesses.
• Determine whether the fmserver servlet (or the DCNM web/management interface that hosts it) is enabled and from which networks it is reachable.
• Review firewall, load-balancer, and reverse-proxy rules that expose DCNM management ports.

Telemetry and log signs of possible exploitation are general for this class: unusual HTTP requests to the DCNM web interface containing path traversal patterns, repeated access to the fmserver-related endpoints, or unexpected file-read activity originating from the DCNM process. Correlate web access logs, application logs, and host filesystem access logs. Absence of clear signatures in public detail means you should baseline normal DCNM traffic and investigate anomalies rather than waiting for a specific IOC list.

How to remediate

Patch first. Apply the updates Cisco published for this vulnerability, following the vendor instructions referenced in the CISA guidance (“Apply updates per vendor instructions”). Confirm the exact fixed release and any prerequisite steps in the official Cisco advisory before rolling out.

After patching:

• Verify the updated build is running and that the previously affected servlet behavior is no longer present (per vendor test guidance).
• Restrict management-plane access to DCNM so only authorized operations networks and jump hosts can reach the web interface.
• Ensure DCNM runs with least privilege and that sensitive files on the host are permissioned so a compromised application account cannot read more than necessary.
• Re-review any custom integrations or scripts that call DCNM APIs or servlets so they do not reintroduce unsafe path handling.

If you can't patch immediately

Until the vendor update is installed, reduce exposure with compensating controls appropriate to a remote arbitrary-file-read flaw on a management server:

• Segment DCNM onto a tightly controlled management network; block direct access from user LANs and the internet.
• Place a reverse proxy or WAF in front of the interface and deny requests that contain directory-traversal sequences or that target the fmserver servlet paths if those paths are not required for normal operations (validate rules so you do not break legitimate admin use).
• Disable or unload unused web components or servlets if the product and your operational needs allow it; confirm with Cisco documentation.
• Enforce strong authentication and, where supported, multi-factor authentication for all DCNM administrative access; limit accounts to the minimum set of operators.
• Increase monitoring: alert on anomalous requests to the DCNM web tier, unexpected outbound connections from the DCNM host, and reads of sensitive system or configuration files by the DCNM process.
• Maintain offline, access-controlled backups of DCNM configuration and related network device configs so you can recover if the host is later found compromised.

These measures lower risk; they do not replace the patch.

If your data may have been exposed

Actively exploited vulnerabilities of this type can lead to breaches if an attacker obtains credentials, configuration, or other sensitive files from the management server. Known ransomware use is not documented for this CVE. If you have reason to believe the DCNM host was reachable and unpatched during a period of exposure, treat it as a potential incident: isolate the system as needed, preserve logs, rotate any credentials that may have resided on the host or in readable configs, and follow your incident-response process. You can also run a free exposure scan of your email addresses against known breach data to see whether associated accounts appear in public breach corpora while you complete internal investigation.