Kaspersky Labs, a leading information security software developer, has detected Cabir, the first network worm which propagates via mobile networks. It infects telephones running Symbian OS. So far, Cabir does not seem to have caused any security incidents.

It seems that the worm was writtten by "Vallez". This pseudonym is used by 29a, an international group of virus writers. The group specialises in creating proof-of-concept viruses. Among the group's creations are Cap, the first macro virus to cause a global epidemic; Stream, the first virus for additional NTFS streams; Donut, the first virus for .NET and Rugrat, the first Win64 virus.

Preliminary analysis of the malicious code shows that that Cabir is transmitted as an SIS file (Nokia Phone Game File), but the file is disguised to be a Caribe Security Manager utility, part of the telephone security software. If the infected file is launched, the telephone screen will display the inscription "Caribe". The worm penetrates the system and will then be activated each time the phone is started. Cabir scans for all accessible phones using Bluetooth technology, and sends a copy of itself to the first one found.

Analsysis of the worm's code has not so far detected any malicious payload.

The worm is coded to run under Symbian OS, used in many Nokia telephones. However, it is possible that Cabir will function on handsets produced by other manufacturers.

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