The Israeli company behind the modified Signal app used by the Trump administration has been hacked.

TeleMessage’s backend panel was accessed using credentials found in intercepted data. The hacker exposed archived messages and contact info for U.S. officials.

The hack reveals that archived chat logs are not end-to-end encrypted between the modified messaging app and the final archive destination controlled by the TeleMessage customer.

Commenting on the Israeli modification of Signal adopted by the US government, @signalapp told @404media that “We cannot guarantee the privacy or security properties of unofficial versions of Signal.”