[Sib3r]

This threads information will be coming from a Kaspersky Lab Expert as of 6/6/13.

Hey guys I will try to put this in my own words so I am not just copying the article. There is a new android trojan that has been labeled as the most sophisticated trojan for a android device that has ever been made. The trojan has been named Backdoor.AndroidOS.Obad.a. Now in most cases the coders of the virus try to make really complex and hard code to decipher and to stay ahead and make life hard for malware experts.

Some features of the trojan:

• 
  


• sending SMS to premium-rate numbers
  


• downloading other malware programs
  


• installing them on the infected device and/or sending them further via Bluetooth
  


• remotely performing commands in the console
  

[img]http://www.securelist.com/en/images/vlweblog/android_trojan_01s.png[/img]

First let me start by sadly informing users that once this trojan gains extended privileges it is impossible to remove and it also runs in background mode and does not have a interface. The way that the trojan can find itself onto your phone is because there is a error that the coders found in the popular DEX2JAR software. This program is typically used by analysts to convert APK files into the more convenient Java Archive (JAR) format which will eventually complicate the statistical analysis on the trojan. There is also an error in the Android operating system which relates to the processing of the AndroidManifest.xml file which is in every android application and is used to describe the application's structure, define its launch parameters, etc. The malware modifies AndroidManifest.xml in such a way that it does not comply with Google standards, but is still correctly processed on a smartphone thanks to the exploitation of the identified vulnerability.

In this malicious application, all external methods are called via reflection. All strings are encrypted, including the names of classes and methods.

[img]http://www.securelist.com/en/images/vlweblog/android_trojan_02.png[/img]

Each class has a local descriptor method which obtains the string required for encryption from the locally updated byte array. All strings are “hidden” in this array.

[img]http://www.securelist.com/en/images/vlweblog/android_trojan_03.png[/img]

The most important strings containing the C&C address undergo an additional stage of decryption. For this, the Trojan first checks if Internet access is available, then downloads the page facebook.com. It extracts a certain element of that page, and uses it as decryption key. Thus, Backdoor.AndroidOS.Obad.a can only decrypt C&C addresses when Internet access is available. This feature further complicates the analysis of this piece of malware.

Some strings are additionally encrypted. The local decryptor receives a coded string in Base64 and decodes it. The decoded string is first decrypted with XOR operation with the MD5 of the key, then additionally decrypted with the MD5 of the string "UnsupportedEncodingException". To obtain the MD5 of the key, the same local decryptor decrypts yet another string, which is then used as an argument for MD5. In this way, key strings, such as the name of the function SendTextMessage, are protected.

[img]http://www.securelist.com/en/images/vlweblog/android_trojan_04.jpeg[/img]

Below is a image of the deciphered strings:

[img]http://www.securelist.com/en/images/vlweblog/android_trojan_05.png[/img]

Immediately after it starts, the application attempts to obtain Device Administrator privileges. As stated above, one feature of this Trojan is that the malicious application cannot be deleted once it has gained administrator privileges: by exploiting a previously unknown Android vulnerability, the malicious application enjoys extended privileges, but is not listed as an application with Device Administrator privileges.

[img]http://www.securelist.com/en/images/vlweblog/android_trojan_06.jpeg[/img]

Google has already been informed about the Device Administrator vulnerability in Android. With the extended Device Administrator Privileges, the Trojan can block the device’s screen for up to 10 seconds. This typically happens after the device is connected to a free Wi-Fi network or Bluetooth is activated; with a connection established, the Trojan can copy itself and other malicious applications to other devices located nearby. It’s possible that this is how Backdoor.AndroidOS.Obad.a tries to prevent the user from discovering its malicious activity. Also, the Trojan attempts to obtain root privileges by performing the command “su id”.

The information about whether superuser privileges have been successfully obtained is sent to the C&C server. Obtaining root privileges can put cybercriminals in an advantageous position when executing commands on the console remotely. After the first launch, the malicious application collects the following information and sends it to the C&C server at androfox.com:

• 
  


• MAC address of the Bluetooth device
  


• Name of operator
  


• Telephone number
  


• IMEI
  


• Phone user’s account balance
  


• Whether or not Device Administrator privileges have been obtained
  


• Local time
  

[img]http://www.securelist.com/en/images/vlweblog/android_trojan_09.png[/img]

This information is sent to the current C&C server every time a connection is established. In addition the malicious program reports its current status to its owner: it sends the current table of premium numbers and prefixes to which to send text messages (the “aos” parameter), the task list (“task”), and the list of C&C servers. During the first C&C communication session, it sends a blank table and a list of C&C addresses that were decrypted as described above. During the communication session, the Trojan may receive an updated table of premium numbers and a new list of C&C addresses.

In response, the C&C server sends another JSON object which might look like this after decryption:

{"nextTime":1,"conf":{"key_con":"oKzDAglGINy","key_url":"3ylOp9UQwk",
"key_die":"ar8aW9YTX45TBeY","key_cip":"lRo6JfLq9CRNd6F7IsZTyDKKg8UGE5EICh4xjzk"}}

NextTime is the next connection to a C&C server

conf are configuration strings.

Configuration strings can contain instructions to connect to new C&C servers, tables of numbers with prefixes and keys with destinations for text messages, and new tasks with parameters. Besides, keys for traffic encryption (key_cip) may be sent to conf.

Cybercriminals can also use text messages to control the Trojan. Configuration strings may also contain key strings (key_con, key_url, key_die) that the Trojan will look for in incoming text messages, and perform certain actions accordingly.

Each incoming text message is analyzed for the presence of any of these keys. If a key is found, the appropriate action is performed: key_con: immediately establish a C&C connection; key_die: delete tasks from the database; key_url: connect to a new C&C server. This instruction must be followed by the new C&C address. This way the cybercriminal can create a new C&C server and send its address to infected devices in text messages containing this key. This will make all infected devices reconnect to the new server. If a “send text message” instruction key is found in conf, the Trojan sends a message to the numbers provided by C&C. Thus, the infected devices do not even need to have an Internet connection to receive an instruction to send charged text messages.

[img]http://www.securelist.com/en/images/vlweblog/android_trojan_10.png[/img]

The Trojan receives instructions from the C&C and records them in the database. Each instruction recorded in this database contains the instruction’s sequence number; the time when it must be executed, as ordered by C&C; and parameters.

Command list:

• 
  


• Send text message. Parameters contain number and text. Replies are deleted.
  


• PING.
  


• Receive account balance via USSD.
  


• Act as proxy (send specified data to specified address, and communicate the response).
  


• Connect to specified address (clicker).
  


• Download a file from the server and install it.
  


• Send a list of applications installed on the smartphone to the server.
  


• Send information about an installed application specified by the C&C server.
  


• Send the user’s contact data to the server.
  


• Remote Shell. Executes commands in the console, as specified by the cybercriminal.
  


• Send a file to all detected Bluetooth devices.
  

This command list for Obad.a enables the malicious program to spread files via Bluetooth. The C&C server sends the Trojan receives the local address of the file to be downloaded to the infected devices. On a C&C command, the malicious program scans for nearby devices with enabled Bluetooth connection, and attempts to send the downloaded file to them.

Despite such impressive capabilities, Backdoor.AndroidOS.Obad.a is not very widespread. Over a 3-day observation period using Kaspersky Security Network data, Obad.a installation attempts made up no more than 0.15% of all attempts to infect mobile devices with various malware.

To conclude this review, we would like to add that Backdoor.AndroidOS.Obad.a looks closer to Windows malware than to other Android Trojans, in terms of its complexity and the number of unpublished vulnerabilities it exploits. This means that the complexity of Android malware programs is growing rapidly alongside their numbers.

Thank you for taking the time to read all this again I credit a Kaspersky Lab Expert for this information and review of this malware.

[zhejiezhang]

That's some important stuff to look out for! Thanks for the information.

[sabotaz44]

Thank you for this great read.Hf would be a better place with posts like this one.Btw dp you knowany ios viruses?

[Inmodwetrust]

Just quickly scanned through it, looks like a decent read. I'll be sure to read it once I'm home.

[vegetajgd]

This is really a hq post. Thanks a lot for this post.

[Sib3r]

Glad I can help just trying to make the community more aware.

[iyadof]

thanks alot for this post really good info

[Hidden™]

This is one of the best threads I have seen in a while.

[Aura]

Holy fuck this is actually impressive.
Reading the whole thing on my lunch break in like an hour.

[Sib3r]

Holy fuck this is actually impressive.
Reading the whole thing on my lunch break in like an hour.

Thanks I am glad you guys find it impressive I remember when I was making this thread it took me like a hour it was when I use to be in Infamous.

[Aura]

Thanks I am glad you guys find it impressive I remember when I was making this thread it took me like a hour it was when I use to be in Infamous.

Just read the whole thing, it's jaw-dropping, that's actually pretty impressive. For someone like me that knows Android Dev. it's very very impressive. Good thing Kaspersky inspected that malware, I trust their researchers and reviews too.

[Jagster™]

Holy fuck this is actually impressive.
Reading the whole thing on my lunch break in like an hour.

And its a year old newb :P

but yah this is some OG malware right here. I feel like this is the shit NSA does to everyone🤫