Yxe trojan infecting mobile phones

Symbian software-signing slipup certifies SMS spambot.

A new trojan, the first of its kind, is affecting users of the Symbian mobile operating system by spreading itself via text messages sent to all numbers in the phone's address book. These messages contain a link, clicking on which will attempt to install an application Sexy Space, which in fact is a copy of the trojan. Because it has been signed by Symbian, the user will not get a security warning before installing the application.

Apart from attempting to spread itself, the trojan, dubbed Yxe, Sexy Space or Sexy View, sends information about the phone to a control center. The trojan also downloads fresh message templates, which has caused it to be called a 'mobile botnet' by some researchers. It is not known whether the trojan has any further payload.

Symbian, which owns almost half of the smartphone OS-market, has admitted it made a mistake in not manually checking the malware. It has revoked the certificates, but the revokation is not immediately distributed to the hundreds of millions of Symbian users.

While the impact of the trojan is not very big and mainly concerns customers in China and the Middle East, it shows that users of smartphones, many of whom do not have anti-virus software installed, should not consider themselves safe from malware.

More on the trojan, including a guide on how to enforce phones to receive revokation certificates, at F-Secure's weblog here, while comments from Symbian can be found at CNET here.

21 July 2009

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