Cisco Unity Connection Directory Traversal Vulnerability

A vulnerability in the attachment service of Cisco Unity Connection, known as Cisco Unity Web Service or as Voice Message Web Service (VMWS), could allow an authenticated, remote attacker to place files in arbitrary locations on an affected device.

The vulnerability is due to a failure to properly sanitize user-supplied input provided as part of a file name to the VMWS attachment service. An attacker could exploit this vulnerability by supplying the path to the desired file location utilizing directory traversal characters. An exploit could allow the temporary placement of an attacker-controlled file into any location writeable by the Apache Tomcat service.

When files are uploaded, the VMWS Attachment service validates the supplied file and immediately removes the file if it is not determined to be an audio file. This creates a short window that could be used to access the attacker-controlled file. If placed in the proper location on the device, an extended impact of this vulnerability could allow the attacker to execute arbitrary Java Server Pages (JSP) code within the context of Apache Tomcat.

Cisco would like to thank Jason Sinchak for reporting this vulnerability.

Cisco has confirmed the vulnerability and released software updates.

To exploit this vulnerability, an attacker must authenticate to place arbitrary files in certain locations on an affected device. This access requirement decreases the likelihood of a successful exploit.

If the VMWS recognizes a file other than an audio file, the service would remove the file, which shortens the window of an affected device accessing an arbitrary file uploaded by an attacker.

Cisco indicates through the CVSS score that functional exploit code exists.