Some mobile apps use SMTP as the underlying protocol when submitting large files or photos. The content of these submissions would also be vulnerable to this mass surveillance.
The STRIPTLS proxy is present on both True Internet and TOT ADSL connections, the two largest ISPs in Thailand. It is not present on Dtac 3G or on AIS 3G.
The source, speaking on condition of anonymity, said the attack has been live for at least couple of weeks if not much longer.
Neither Google or Yahoo responded to emails asking for comment by time of going to press.