January 2008

ID: 3554
Date: 23/01/2008

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Title: 3554 - Malicious Software Report - SymbOS/Beselo.A! and variants
Platform level affected:Operating System
Hardware components affected:Telephony
Specific operating systems components affected: Other
Other software: Other
Remediation Summary:Special Event. Be on your guard at this time.
Vendors affected:Various
Applications affected:Symbian S60 Operating System
Adversity source: Unknown
Attack Vector: Malware
Virulence: Self-Replicating - Slow
Warning Status: Active
Potential Damage: Privilege escalation
Possible Duration: Open Ended
Availability of fix: Future
Type of fix: None
Source: Media and Anti Virus Vendors
Reliability of source: Known
Abstract: Details of a new worm infecting certain types of mobile phones.

CPNI has been made aware of a new mobile phone Worm, known as SymbOS/Beselo.A! (also Beselo.B!).  This Worm only affects handsets running the Symbian S60 Operating System.SymbOS/Beselo.A! and variants use the Multimedia Messaging System (MMS) to send itself to phone numbers found on an infected phone.  The worm can also be transmitted via Bluetooth.

SymbOS/Beselo relies on users possible unfamiliarity with how appplications are installed on Symbian phones. Viewing media files(jpg, rm, mp3, etc.) on Symbian does not usually require installing addtional software and definitely doesnt require one to install from an MMS message.

CPNI recommends that that all mobile phone users exercise caution when opening MMS files and installing applications.

The malware is considered a LOW threat but further information can be obtained from the following URLs:

http://www.fortiguardcenter.com/VirusEncyclopedia/search/encyclopediaSearch.do?method=quickSearchDirectly&virusName=SymbOS/Beselo.A!worm

http://www.avertlabs.com/research/blog/index.php/2008/01/23/pics-from-a-friend-maybe-not/

http://www.f-secure.com/weblog/

This advisory contains information released by the original author. Some of the information may have changed since it was released. If the issue affects you, it may be prudent to retrieve the advisory from the site of the original source to ensure that you receive the most current information concerning that problem. Reference to any specific commercial product, process, or service by trade name, trademark manufacturer, or otherwise, does not constitute or imply its endorsement, recommendation, or favouring by CPNI.

The views and opinions of authors expressed within this notice shall not be used for advertising or product endorsement purposes. CPNI shall not accept responsibility for any errors or omissions contained within this advisory. In particular, they shall not be liable for any loss or damage whatsoever, arising from or in connection with the usage of information contained within this advisory.

CSIRTUK is a member of the Forum of Incident Response and Security Teams (FIRST) and has contacts with other international Incident Response Teams (IRTs) in order to foster cooperation and coordination in incident prevention, to prompt rapid reaction to incidents, and to promote information sharing amongst its members and the community at large.