Sunday, February 22, 2009

Mobile worm, Yxes.A spreading on Nokia smartphones

F-Secure and FortiGruard both reported that a new worm,Yxes.A, is spreading on Nokia smartphones based on S60 3rd Edition platform (and probably higher, too). According to FortiGuard:

* "It gathers phone numbers from the infected device's file system, and repeatedly attempts to send SMS messages to those. The messages feature a malicious Web address (URL); upon "clicking" on the address in the received message, the recipients will download a copy of the worm (provided their phones/subscriptions allow for internet browsing)." That is, it's a Trojan.
* Beyond propagating to as many users as possible via the strategy mentioned above, the worm's aim is to gather intelligence on the infected victim (such as serial number of the phone, subscription number) and post it to a remote server likely controlled by cyber criminals.
* It's also noted that worm can mutate easily: "As far as our analysis goes, the worm currently does not take commands from the remote servers it contacts. However, since the copies hosted on the malicious servers are controlled by the cyber criminals, they may update them whenever they want, thereby effectively mutating the worm, adding or removing functionality." It's not that simple, though. It's not like download a new EXE from the Net and it will just work. No new EXE or DLL (a plug-in, for example) can be installed without the assistance of Application Installer, which will eventually require user's attention and approval. Some files that don't have to be installed can be downloaded, though, containing instructions for the worm to execute, however, it's becoming a science fiction if we think that any malware author will put THAT much effort in developing such a system. I'm highly sceptical on that it would be a real threat and refuse to be threatened by that.
* It's also reported that "On launch, the worm executes as the process 'EConServer.exe', which is likely meant to camouflage alongside the existing legitimate system process 'EComServer.exe'". This simply doesn't mean anything: if a process name is only similar to another (system) process name then it doesn't imply anything. And anyway, EComServer.exe is never launched by hand (but by the system upon device start), consequently it's not a valid scenario that the malicious EXE gets launched instead.
* It's a very agressive application, since it "will also automatically run every time the device is rebooted / power cycled. Further, it bears a destructive nature and will kill certain processes such as the application manager (AppMgr)." If that's true then the program must hold very strong capabilities that cannot be granted by a self-signed certificate.

No comments: