Home assistant is an open source home automation. Whilst auditing the frontend code to identify hidden parameters, Cure53 detected authcallback=1, which is leveraged by the WebSocket authentication logic in tandem with the state parameter. The state parameter contains the hassUrl, which is subsequently utilized to establish a WebSocket connection. This behavior permits an attacker to create a malicious Home Assistant link with a modified state parameter that forces the frontend to connect to an alternative WebSocket backend. Henceforth, the attacker can spoof any WebSocket responses and trigger cross site scripting (XSS). Since the XSS is executed on the actual Home Assistant frontend domain, it can connect to the real Home Assistant backend, which essentially represents a comprehensive takeover scenario. Permitting the site to be iframed by other origins, as discussed in GHSA-935v-rmg9-44mw, renders this exploit substantially covert since a malicious website can obfuscate the compromise strategy in the background. However, even without this, the attacker can still send the authcallback link directly to the victim user. To mitigate this issue, Cure53 advises modifying the WebSocket code’s authentication flow. An optimal implementation in this regard would not trust the hassUrl passed in by a GET parameter. Cure53 must stipulate the significant time required of the Cure53 consultants to identify an XSS vector, despite holding full control over the WebSocket responses. In many areas, data from the WebSocket was properly sanitized, which hinders post-exploitation. The audit team eventually detected the jsurl for custom panels, though generally, the frontend exhibited reasonable security hardening. This issue has been addressed in Home Assistant Core version 2023.8.0 and in the npm package home-assistant-js-websocket in version 8.2.0. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Home assistant is an open source home automation. The Home Assistant Companion for Android app up to version 2023.8.2 is vulnerable to arbitrary URL loading in a WebView. This enables all sorts of attacks, including arbitrary JavaScript execution, limited native code execution, and credential theft. This issue has been patched in version 2023.9.2 and all users are advised to upgrade. There are no known workarounds for this vulnerability. This issue is also tracked as GitHub Security Lab (GHSL) Vulnerability Report: GHSL-2023-142.

The Home Assistant Companion for iOS and macOS app up to version 2023.4 are vulnerable to Client-Side Request Forgery. Attackers may send malicious links/QRs to victims that, when visited, will make the victim to call arbitrary services in their Home Assistant installation. Combined with this security advisory, may result in full compromise and remote code execution (RCE). Version 2023.7 addresses this issue and all users are advised to upgrade. There are no known workarounds for this vulnerability. This issue is also tracked as GitHub Security Lab (GHSL) Vulnerability Report: GHSL-2023-161.