CVE-2017-9387

/// Technical description

An issue was discovered on Vera VeraEdge 1.7.19 and Veralite 1.7.481 devices. The device provides a shell script called relay.sh which is used for creating new SSH relays for the device so that the device connects to Vera servers. All the parameters passed in this specific script are logged to a log file called log.relay in the /tmp folder. The user can also read all the log files from the device using a script called log.sh. However, when the script loads the log files it displays them with content-type text/html and passes all the logs through the ansi2html binary which converts all the character text including HTML meta-characters correctly to be displayed in the browser. This allows an attacker to use the log files as a storing mechanism for the XSS payload and thus whenever a user navigates to that log.sh script, it enables the XSS payload and allows an attacker to execute his malicious payload on the user's browser.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References