Anyone heard of a android virus/trojan yet?

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Sometimes I come across an app thats not on the Android market and you have to install it manually. Has anyone come across a virus/trojan on Android yet? Im curious how easy or hard it is to modify a legit applications and put a virus/trojan in it?

Lol have not seen one yet. Android isn't that big yet so doubt hackers would really spend time putting trojans to get stuff like your email password lol.

Take everything you know about microshaft windoze and forget it. The system architecture of android is almost completely invulnerable to viruses/worms/etc.

In a typical unix system, hacks can take one of very few possible approaches;

1) service bug targeting, i.e., if one were to discover a security vulnerability in the Apache HTTP server, one could theoretically compromise it. That particular service I mean.

2) user account targeting, i.e., one could convince a user to run something dangerous, which would infect that specific user's account, of course, this attack would limit itself to damaging that user's personal data and would not be able to take down the whole system unless it also targeted a kernel or X-server exploit.

Note specifically regarding #1, that in a well configured system, that targeting a particular service would be restricted to a specific user account just as in #2 since each service runs as its own username.

3) Targeting KERNEL defects; this is perhaps the most frightening possibility. It is also the least likely since it would also require #1 or #2. Any particular kernel attack, particularly in Linux is also very unlikely to work for long due to the open sourced nature of Linux. There are a LOT more people involved in monitoring the fundamental securities of the Linux kernel than any other OS because of its open nature. It is also a source of PRIDE for kernel HACKERS that they ALSO be responsible for openly providing the SOLUTION to any exploits that they discover. And they usually do this with their REAL NAME since it basically immortalizes them. The end result is that every time a kernel exploit is discovered, it tends to be patched within hours of its first application.


Now of course you want to know how this affects Android, since by all appearances, there is no user-level security. WRONG. The Android security level is actually on par with service level security on unix servers. EVERY SINGLE application installed is granted is own user account, which means that if any particular application is dangerous, its range of damage is restricted to that particular application's private data, as well as any permissions that the application is explicitly granted (i.e. when you install an application, it gives you the required security list). There is also the very slim possibility of a kernel exploit (though this is extremely unlikely), and it could damage the data on the sdcard (since it is an MS-crap filesystem with no security restrictions).

Of course you will note that older versions of the ADP1 system image came with an unregulated 'su' command (which you could also end up with using a "cat sh > su; chmod 4755 su" root approach) which basically can be used by any application to take over the whole system. Make sure that you don't have any such su command on your droid. Either use a password-protected su command (which will cause problems for trusted apps requesting root privileges), or the gui-supported su command. Subsequent ADP1 images came with an su command that was restricted to the debugging terminal user, which is fine.



In other words... you don't have much to worry about. Just don't do anything really stupid, like installing an untrusted application that wants a boat load of privileges that it shouldn't be asking for.

Originally Posted by lbcoder

EVERY SINGLE application installed is granted is own user account, which means that if any particular application is dangerous, its range of damage is restricted to that particular application's private data, as well as any permissions that the application is explicitly granted (i.e. when you install an application, it gives you the required security list).

Might be worth pointing out that android apps are for the most part interpreted language apps, meaning the onus of security and stability (just from an apk standpoint) falls largely on the vm. All the lower level subsystems are pretty well protected by the Linux kernel, and these have been significantly tried in fire by decades of Linux server deployment.

Originally Posted by lbcoder

The system architecture of android is almost completely invulnerable to viruses/worms/etc.

Originally Posted by jashsu

Might be worth pointing out that android apps are for the most part interpreted language apps, meaning the onus of security and stability (just from an apk standpoint) falls largely on the vm. All the lower level subsystems are pretty well protected by the Linux kernel, and these have been significantly tried in fire by decades of Linux server deployment.

All the points about the protection offered from the Linux kernel and the VM are valid. Computer secuity is an ongoing battle between the software originators and the hackers trying to get in. I'm not saying it's remotely likely, particularly due to the market share, but rule one in my book is don't taunt the hackers.

Originally Posted by lbcoder

Take everything you know about microshaft windoze and forget it. The system architecture of android is almost completely invulnerable to viruses/worms/etc.

Until the Android Dev team screw up again and lets any app run in the system process when requested (which was why cupcake was delayed in the US).

thanks for the post.

I was curious if someone could unpack a .apk file and modify a application easily, say have it send personal info to xyz server instead of the server the app was designed for or send it to both servers so the user doesnt think anything is wrong.

Are the files in the .apk editable, like an .exe is compiled for windows and the .exe cannot be edited (since its machine code).

Originally Posted by androidmonkey

thanks for the post.

I was curious if someone could unpack a .apk file and modify a application easily, say have it send personal info to xyz server instead of the server the app was designed for or send it to both servers so the user doesnt think anything is wrong.

Are the files in the .apk editable, like an .exe is compiled for windows and the .exe cannot be edited (since its machine code).

Yes, apks are basically just zip files with cryptographic signatures. If you get your apks from Market then there is little to no risk of apks being tampered with. If you install your apks from any source other than Market, then you just have to trust the source that the apk hasn't been modified. Obviously if the apk itself doesn't ask for many permissions then it shouldn't be a problem. For example if you download a game apk from a developer's personal webpage and it asks for just permission to keep the screen alive, there's little risk to your data. However if you download an app that has read/write access to your contacts, or has root access, then you better be sure that the site you get it from is trustworthy.

Originally Posted by jashsu

Yes, apks are basically just zip files with cryptographic signatures. If you get your apks from Market then there is little to no risk of apks being tampered with. If you install your apks from any source other than Market, then you just have to trust the source that the apk hasn't been modified. Obviously if the apk itself doesn't ask for many permissions then it shouldn't be a problem. For example if you download a game apk from a developer's personal webpage and it asks for just permission to keep the screen alive, there's little risk to your data. However if you download an app that has read/write access to your contacts, or has root access, then you better be sure that the site you get it from is trustworthy.

So the files in the .apk not executables, rather interpreted with the VM? Im curious if those files can be read and changed. For instance, can someone open the file in a Java SDK and change the code? Or are those files protected so they cant be modified? For instance, could you download soundboard app from the Market, "unzip" the .apk, and put your own sounds in it?

Originally Posted by androidmonkey

So the files in the .apk not executables, rather interpreted with the VM? Im curious if those files can be read and changed. For instance, can someone open the file in a Java SDK and change the code? Or are those files protected so they cant be modified? For instance, could you download soundboard app from the Market, "unzip" the .apk, and put your own sounds in it?

Unless the classes are specifically performing security/sanity checks, there's nothing keeping you from replacing asset files (pngs, wavs, etc) and then resigning the apk with any key of your choosing. However, altering xmls and classes is more difficult as they are obfuscated/optimized by default.

For apps distributed officially through the Android market, the only way Google can provide assurance for the app producer against tampering is app-protected folder. Of course that assumes that root access is not provided, which is most likely a prerequsite for any phone to be branded "with Google" and have Market access. From the viewpoint of the consumer, apps are guaranteed by Google against tampering only if retrieved through Market. Once the app is on the device, it is protected via Android's use of Linux user access permission model (each app is its own user). The consumer may of course alter the file him/herself, unless it is a protected app, in which case root is required.