FortiGuard Advisory (FGA-2008-03)
New SymbianOS Worm Spreading In-The-Wild  Figure 1: Incoming Virus The worm, deemed SymbOS/Beselo.A!worm is able to run on several Symbian S60 enabled devices. These devices include, but may not be limited to, Nokia 6600, 6630, 6680, 7610, N70 and N72 phones. After an installation phase, the worm engages in a propagation routine: phone numbers located in the contact list of the devices are harvested, and targeted by viral MMS carrying a SIS-packed (Symbian Installation Source) version of the worm. However, the SIS file does not bear a .sis file extension -- rather, it is disguised as a multimedia file with an evocative name: Beauty.jpg, Sex.mp3 or Love.rm. Unlike Microsoft Windows, SymbianOS types files based on their content and not their extensions, so it is worth noting that recipients of infected MMS would still be presented with an installation dialogue upon "clicking" on the attachment. Therefore, users could easily be deceived by the extension and unknowingly install the malicious piece of software. In addition to harvesting the numbers stored in the phone address book as mentioned above, the Beselo worm sends itself to generated numbers as well. Interestingly, all those numbers are located in China and belong to the same mobile phone operator. Some of those numbers have been verified to belong to actual customers, rather than being premium service numbers. The whys and hows of such a routine are still under investigation.  Figure 2: Worm Propagation Although the prevalence of this mobile malware incident is still low, the FortiGuard Global Security Research Team will continue to monitor the situation and update the description with new findings as needed. Users may know they have been infected if they see unrecognized sent messages in their MMS outboxes (the device needs to be configured to save such messages). FortiClient Mobile automatically detects and removes the Beselo worm. For users without FortiClient Mobile who believe they may be infected, please contact your mobile carrier or phone manufacturer for technical support in manually removing the virus. For more information on SymbOS/Beselo.A!worm, visit the Virus Encyclopedia. Credits: Many thanks to Dawid, the defense manager of a large, large mobile operator that has deployed our product to protect its customers from malevolent MMS messages -- and who spotted the worm first. Disclaimer: Although Fortinet has attempted to provide accurate information in these materials, Fortinet assumes no legal responsibility for the accuracy or completeness of the information. More specific information is available on request from Fortinet. Please note that Fortinet's product information does not constitute or contain any guarantee, warranty or legally binding representation, unless expressly identified as such in a duly signed writing. About Fortinet ( www.fortinet.com ): Fortinet is the pioneer and leading provider of ASIC-accelerated unified threat management, or UTM, security systems, which are used by enterprises and service providers to increase their security while reducing total operating costs. Fortinet solutions were built from the ground up to integrate multiple levels of security protection--including firewall, antivirus, intrusion prevention, VPN, spyware prevention and anti-spam -- designed to help customers protect against network and content level threats. Leveraging a custom ASIC and unified interface, Fortinet solutions offer advanced security functionality that scales from remote office to chassis-based solutions with integrated management and reporting. Fortinet solutions have won multiple awards around the world and are the only security products that are certified in six programs by ICSA Labs: (Firewall, Antivirus, IPSec, SSL, Network IPS, and Anti-Spyware). Fortinet is privately held and based in Sunnyvale, California. |
