Hackers possibly linked to the Kremlin exploited previously patched iOS and Android flaws in an attempt to hack visitors of multiple websites, including one celebrating the 250th anniversary of the signing of the US Constitution, researchers said Wednesday.

The attackers, which the researchers assessed with “moderate to high confidence” were part of Russia’s Foreign Intelligence Service, targeted other sites, many with links to that country’s ongoing war against Ukraine. The attacks began when iPhone or Android users visited one of potentially hundreds of different sites. JavaScript injected into the traffic then profiled the device. The final payloads, tailored to the type of platform visiting, attempted to steal browser cookies and, in some cases, Wi-Fi passwords and full mobile device data.

Wielding DarkSword

One of the impersonated sites was america250.org, belonging to a non-partisan group of lawmakers, business executives, and at least one former member of the Trump administration.…